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Kačírek, David. "Optimalizace procesních parametrů pro laserové svařování tenkostěnných polotovarů z nerezavějící oceli." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241941.
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For increase productivity, the current technology of welding pipes bellows was replaced by laser welding. Experiment was carried out on the material of austenitic stainless steel 1.4541 for sheet thickness 0.25 mm and 0.15 mm. On sheet 0.25 mm was achieved comparable mechanical properties as the current manufacturing process upon achieving 10 times higher welding speeds. Samples of 0.15 mm thickness achieved to about 30% lower deepening over existing technology. For improvement was advised to reduce heat input. From an economic assessment shows that the price per 1 m of weld decreases with increasing speed welding. With higher welding speeds reduces the heat input.
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Ribardo, Charles Louis. "Desirability functions for comparing arc welding parameter optimization methods and for addressing process variability under six sigma assumptions /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488203857249003.
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Ballat-Durand, Dorick. "Microstructural characterization and optimization of linear friction welded titanium alloys joints through the influence of the process parameters and post-weld heat treatments." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2499.
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Cette étude s’inscrit dans une démarche de réduction des coûts dus à l’utilisation croissante d’alliages de titane pour des applications structurelles, via des procédés d’assemblage à l’état solide, comme le soudage par friction linéaire (LFW). Cependant, les chargements thermomécaniques transmis au matériau au cours du LFW engendrent d’importantes transformations microstructurales pouvant affecter sévèrement la durabilité mécanique de l’assemblage. Ces transformations sont dépendantes à la fois de l’histoire thermomécanique du matériau et de ses éléments d’alliage. Ainsi, la compréhension des mécanismes régissant ces transformations en lien avec l’impact des configurations procédé et/ou de traitements thermiques sur ces dernières apparaît comme nécessaire pour des applications industrielles. Les travaux présentés dans ce document se focalisent sur la caractérisation/optimisation microstructurale de deux joints obtenus à partir de deux alliages sensiblement différents : le β-métastable Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti17) et le quasi-α Ti-6Al-2Sn-4Zr-2Mo (Ti6242). Une analyse détaillée des mécanismes impactant les transformations microstructurales et la résorption des défauts sera exposée en s’appuyant sur des études multi-techniques et multi-échelle. Ces campagnes expérimentales ont conduit à l’élaboration d’un traitement thermique permettant d’obtenir des comportements mécaniques quasi-homogènes au sein des structures soudées. De plus, les effets des principaux paramètres de LFW sur les microstructures ont été déterminés fournissant ainsi à la littérature des données essentielles pour la dissipation des défauts et le contrôle des textures de déformationThe present study follows up two major development axes focusing on the increase in use of Ti-alloys for structur applications through the use of solid-state joining processes such as Linear Friction Welding (LFW). Yet, the therm mechanical loads involved during LFW result in remarkable microstructural changes deeply affecting the associate mechanical performances. These changes are concomitant with the thermo-mechanical processing history and the alloyin compositions of the welded Ti-alloys. Hence, a correct understanding of the microstructure transformation mechanism induced by LFW is required as well as identifying the influence of the process conditions and/or complementary he treatments on these changes. This dissertation is endeavored at characterizing and optimizing the microstructures of two butt-joints of significantl different Ti-alloys: the ß-metastable Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti17) and the near-α Ti-6Al-2Sn-4Zr-2Mo (Ti6242). The extensive microstructural investigations will focus on identifying the mechanisms responsible for transforming the microstructures and for the formation/resorption of welding defects. These investigations will combine temperatur measurements, micrographs, crystallographic/chemical analysis, hardness/tensile tests. The resulting comprehension the microstructural changes will enable designing a heat treatment capable of a quasi-homogenization of the tensil behavior across the assemblies. Moreover, identifying the effects of the main process parameters on the microstructur will provide the literature with valuable insights on tailoring the process duration, the recrystallization/textur development, and the defect removal
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Schlickmann, Marcelo Niehues. "Avaliação da influência dos parâmetros do processo de soldagem TIG sobre a qualidade de uma peça fabricada em aço elétrico silicioso." Universidade do Estado de Santa Catarina, 2010. http://tede.udesc.br/handle/handle/1763.
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The TIG welding process (Tungsten Inert Gas), also known as GTAW (Gas Tungsten ArcWelding), is the most commonly used process for welding of thin plates where there is a need for an excellent control of the temperature applied on the piece. This paper presents a study carried out in partnership between the Department of Graduate Studies in Scienceand Materials Engineering and the Department of Industrial Engineering and Stamping of WEG Equipamentos Elétricos S.A Motors Division. It elaborates on the use of the experimental methodology DOE to investigate the influence of TIG welding process parameters, electrical current, welding speed and flow of the shielding gas on the quality of a piece fabricated with silicon electrical steel - ABNT 50F 466M, best known for its 50A 400 specification on the JIS standard. The first step of the study was the designing of the experiment to obtain welded pieces with different combinations of the parameters above mentioned and enable the evaluation of mechanical strength, fillet weld size, hardness and metallographic analysis of the test specimens. The information obtained with analysis of variance techniques (ANOVA) showed that the change in the levels of electrical current and welding speed promotes significant changes in final results. Furthermore, the different rates of gas flow tested caused no differences in response variables of the study. As a result, it was also possible to determine the combinations of these parameters that ensure the required quality and provide increased productivity, energy saving and reduced consumption of the shielding gas.
O processo de soldagem TIG (Tungsten Inert Gas), também conhecido como GTAW (Gas Tungsten Arc Welding), é o processo mais utilizado para a soldagem de chapas finas onde um excelente controle do aporte térmico à peça é necessário. Nesta dissertação é presentado um estudo realizado em parceria entre o Departamento de Pós-Graduação em Ciência e engenharia dos Materiais e os Departamentos de Engenharia Industrial e Estamparia da WEG Equipamentos Elétricos S.A. - Motores. Esse estudo envolveu a utilização da metodologia de delineamento experimental DOE para investigar a influência dos parâmetros do processo de soldagem TIG, corrente elétrica, velocidade de deslocamento da tocha e vazão do gás de proteção, na qualidade de uma peça fabricada com aço elétrico silicioso ABNT 50F 466M, mais conhecido pela classificação 50A 400 da norma JIS. Inicialmente foi elaborado o planejamento do experimento a fim de obter peças soldadas com diferentes combinações dos parâmetros acima mencionados e possibilitar a avaliação da resistência mecânica, dimensão dos cordões de solda, dureza e análise metalográfica dos corpos de prova. Os resultados obtidos, com o auxílio da técnica de análise de variância (ANOVA), mostraram que mudanças nos níveis de corrente e na velocidade de soldagem promoveram alterações significativas nos resultados. Por outro lado, as diferentes taxas de vazão de gás testadas não provocaram diferenças nas variáveis de resposta do estudo. Também foi possível determinar as combinações desses parâmetros que garantem a qualidade requerida e proporcionam aumento de produtividade, economia de energia elétrica e redução no consumo de gás de proteção.
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Jirathearanat, Suwat. "Advanced methods for finite element simulation for part and process design in tube hydroforming." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1071878178.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xxv, 222 p.; also includes graphics (some color). Includes bibliographical references (p. 185-191).
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Melin, Timothy R. "Investigating Wood Welding Parameters Using a Prototype Welding Machine." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/420.
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Understanding how different processing variables influence wood welded bonds is vital if the technique will ever be used to create engineered lumber without using adhesives. A variation of vibration welding, wood welding uses pressure and friction to bond materials together. During welding, heat causes a softening in the wood, a naturally occurring composite material. This softening leads to fiber entanglement and a bond forms upon cooling.
The goal of this research was to investigate several processing aspects of the wood welding procedure. A prototype wood welding machine, designed and fabricated from the ground up, was used to investigate the effects of various welding parameters using birch wood. Wood welds were evaluated on the basis of bond coverage and ultimate shear strength.
Four experiments were performed: welding frequency and duration interaction, grain orientation effects, alternative welding completion metrics, and strength development over time. During the wood welding process, three distinct phenomena were repeatedly observed: smoke creation, welding residue formation, and an audible pitch change. The presence of each was recorded for every wood welded specimen and used later in additional data analysis. Investigating each of the welding phenomena was done in an attempt to better characterize when fusion was achieved at the weld interface.
ImageTool, an image analysis software package, was used to investigate and quantify the often irregular bonds exposed after shear fracture. The results of the various welding variables were analyzed on the basis of shear strength and bond uniformity.
From the birch samples, it was shown that better bonds result from lower welding frequencies and longer welding durations. The grain orientation analysis demonstrated that welding orientation marginally affects the average shear strength of the wood weld. The data from the alternative welding metrics suggests that welding time is not a quality indicator of welding completion (bond coverage). The strength development trials confirmed previous research; wood welds obtain most of their strength in a relatively short period of time.
Douglas fir and poplar both proved to be weldable for the first time, but they were sufficiently weaker than birch. When welding was attempted with Douglas fir under similar pressures used for birch, Douglas fir samples would commonly “washboard.” With reduced welding pressure, Douglas fir formed wood welds more easily.
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Erener, Yavuz. "Analysis Of Welding Parameters In Gas Metal Arc Welding By A Welding Robot." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607766/index.pdf.
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ANALYSIS OF WELDING PARAMETERS IN GAS METAL ARC
WELDING BY A WELDING ROBOT
Erener, Yavuz
M.S., Department of Mechanical Engineering
Supervisor : Prof. Dr. R. Tuna Balkan
Co-Supervisor : Prof. Dr. M. A. Sahir Arikan
September 2006, 130 pages
In Robotic Gas Metal Arc Welding process, the welding parameters controlled by the welder (travel speed of the welding torch, wire feed speed, current, voltage, wire diameter, etc.) should be considered to obtain a desired welding quality. To design an appropriate welding model for the used equipment, the effects of each parameter should be studied by carrying out an adequate number of experiments. The welding process is described by analyzing the experimental data to define the relationships between the welding parameters and process variables. Various regressional models can be suggested to establish the analytical relationships.
In this study, the relationship between bead geometry and voltage, current, travel speed and wire feed speed is established by using a specific computer program developed for this purpose.
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Suder, Wojciech Jerzy. "Study of fundamental parameters in hybrid laser welding." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/7288.
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This thesis undertakes a study of laser welding in terms of basic laser material interaction parameters. This includes power density, interaction time and specific point energy. A detailed study of the correlation between the laser material interaction parameters and the observed weld bead profiles is carried out. The results show that the power density and the specific point energy control the depth of penetration, whilst the interaction time controls the weld width. These parameters uniquely characterise the response of the material to the imposed laser energy profile, which is independent of the laser system. It is demonstrated that by studying the laser welding with respect to the basic laser material interaction parameters also helps explain some phenomenological phenomena in laser welding, such as the effect of beam diameter on the weld profile. In addition a new approach for parameter selection in laser and hybrid laser welding is investigated. A phenomenological model allowing achievement of a particular laser weld on different laser systems is developed. In the proposed method the user specifies the required weld profile, according to the quality requirements and then the model provides combination of laser parameters, which lead to this particular weld on a given laser system. This approach can be potentially used to transfer laser data between different laser systems with different beam diameters. An extensive study of residual stains in laser and hybrid laser welding is carried out. Both processes are compared either at a constant total heat input or at conditions required to achieve the same depth of penetration. The results demonstrate that there is a trade-off between the fit-up tolerance and the residual stress-induced distortion. Hybrid laser welding provides better ability to bridge gaps than the laser welding, but for the price of increased residual stress and distortion. Additionally, industrial study of the sensitivity to fit-up of hybrid laser welding with high deposition rate MIG sources is carried out. This thesis is a part of NEGLAP (Next Generation Laser Processing) project sponsored by EPSRC (Engineering and Physical Sciences Research Council) and Tata Steel. The main objective is to understand the process fundamentals and exploit the usefulness of laser technology in pipe industry.
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Marrero, Robert L. Jr. "Analysis of Variable Insensitive Friction Stir Welding Parameters." ScholarWorks@UNO, 2017. http://scholarworks.uno.edu/td/2385.
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Friction Stir Welding (FSW) was used to perform a Design of Experiment (DOE) to determine the welding parameters effects on yielding consistent mechanical properties across the length of the weld. The travel speed was varied across set forge force and RPM conditions, to find a dataset that will yield consistent mechanical properties independent of the travel speed. Six different welds were completed on two different aluminum panels, the advancing side being Aluminum alloy 2195-T8 at a thickness of .350”, with the retreating side being Aluminum alloy 2219-T851 with a gauge thickness of .360”. A Left-hand Right-hand self-reacting pin tool was used for each weld. The mechanical properties of interest are the Ultimate Tensile Strength, Yield Strength, Elasticity and Hardness. The strengths were evaluated by tensile testing, with the Elasticity being measure post break. Specimens were then polished where macrograph and micrograph analysis was completed. Micro-hardness testing was then completed on the weld nuggets.
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Philander, Oscar. "Mathematical modelling of welding : sensitivity of residual stresses and thermal dilatations on welding parameters." Thesis, Peninsula Technikon, 1998. http://hdl.handle.net/20.500.11838/2227.
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Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 1998.In South Africa, the determination of residual stress distribution and undesirable metallurgical phase fractions that are formed in components during welding are been dealt with in a destructive or semi-destructive manner. This dissertation is an attempt at enhancing the acquisition of residual components found in welded structures. It shows how finite element methods can be used to obtain these results. TIG welding is modeled as a thermo-mechano-metallurgical (TMM) problem. The mathematical and finite element models for welding described in this study is based on the work performed by Ronda and Oliver. These models has not yet fully been incorporated into any of the existing computational tools and therefor, a commercial computational software program, SYSWELD 2, was employed to perform the welding simulations. The Leblond material models are incorporated into this software program, and the model that is used for this study is described in this text. Computational simulations were performed to study the effects that the sensitivity of welding parameters would have on the resulting shape and size of Heat Affected Zones, depth and width of penetration, temperature fields, metallurgical solid phase fractions, as well as residual stress distribution and deformation. The results of these simulations were compared to laboratory experiments.
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Tomás, Bruno Manuel Coelho. "Magnetic pulse welding." Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/4890.
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Zhou, Xingguo. "Friction stir welding simulation, optimization and design." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25244.
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Friction stir welding is an advanced welding technology mainly used to join aluminum alloys but with potential for other materials like steel, titanium and its alloys. The aim of this work is to provide a combination of numerical and experiment tools to understand the mechanisms of friction stir welding, optimizing the friction stir welds and characterizing the material properties for welds. The thesis is broadly divided into three themes. In the first theme, an automatic procedure to estimate friction stir welding model parameters, particularly those difficult to measure directly, is proposed and developed. The proposed methodology is seen to predict heat input power from the welding tool and contact conductivity between the workpiece and its supporting plate in good agreement with experimental temperature history data. In the second theme, discontinuous and distributed cooling methods, which use periodical and non-uniformly distributed cooling medium flow to cool the welding workpieces, are proposed to reduce the residual stress of friction stir welds and investigated using multi-physics numerical simulation to predict transient temperature field, residual stress and mechanical performance of welds. The discontinuous cooling method is found to be more effective than conventional active cooling, leading to a lower drop in induced welding temperature and reduced residual stress. The distributed cooling provides another method to balance residual stress and welding temperature for butt welding. The effect of discontinuous cooling on microstructure is evaluated using the multi-physics model. The third part presents small punch beam testing method to characterize material properties of base material, welded material and material property distribution. The small punch beam test utilizes miniaturized specimen and is therefore suited to measuring material properties in local regions of structure, such as the friction stir welding nugget.
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Novak, Francis G. "A correlation of welding solidification parameters to weld macrostructure." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23596.
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Approved for public release; distribution is unlimitedA 3-D finite difference model simulating single pass autogenous welds was used to predict the temperature fields in HY-80 steel arc weldments at various powers and torch velocities. From the predicted temperature field, two important solidification parameters were calculated at the solid-liquid interface: temperature gradients and crystal growth velocities. These were correlated with the macrostructures observed in actual weldments. For purposes of model validation, the predicted and actual fusion zone sizes were in agreement, as were the predicted time temperature curves compared to those measured with thermocouples embedded in the plate.
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Guendouze, Cheikh. "Computer assisted generation of parameters for resistance spot welding." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319943.
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Greeff, Mary Louise. "The influence of welding parameters on the sensitisation behaviour of 3CR12." Diss., Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-04052007-124929.
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Markgren, Hanna. "Fatigue analysis - system parameters optimization." Thesis, Umeå universitet, Institutionen för fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-151755.
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For a mechanical system exposed to repeated cyclic loads fatigue is one of the most common reasons for the system to fail. However fatigue failure calculations are not that well developed. Often when fatigue calculations are made they are done with standard loads and simplified cases. The fatigue life is the time from start of use until the system fails due to fatigue and there does exist some building blocks to calculate the fatigue life. The aim for this project was to put these building blocks together in a workflow that ca be used for calculations of the fatigue life. The workflow was built so that it should be easy to follow for any type of me- chanical system. The start of the workflow is the load history of the system. This is then converted into a stress history that is used for the calculations of the fatigue life. Finally the workflow was tested with two test cases to see if it was possible to use. In Algoryx Momentum the model for each case was set up and then the load history was extracted for each time step during the simulation. To convert the load history to stress history FEM calculations was needed, this was however not a part of this project so the constants to convert loads to stress was given. Then with the stress history in place it was possible to calculate the fatigue life. The results from both test cases were that it was possible to follow every step of the workflow and by this use the workflow to calculate the fatigue life. The second test also showed that with an optimization the system was improved and this resulted in a longer lifetime. To conclude the workflow seems to work as expected and is quite easy to follow. The result given by using the workflow shows the fatigue life, which was the target for the project. However, to be able to evaluate the workflow fully and understand how well the resluts can be trusted a comparison with empiric data would be needed. Still the results from the tests are that the workflow seem to give reasonable results when calculating fatigue life.
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Samek, Michal. "Optimization of Aircraft Tracker Parameters." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2015. http://www.nusl.cz/ntk/nusl-234937.
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Diplomová práce se zabývá optimalizací systému pro sledování letadel, využívaného pro řízení letového provozu. Je popsána metodika vyhodnocování přesnosti sledovacího systému a přehled relevantních algoritmů pro sledování objektů. Dále jsou navrženy tři přístupy k řešení problému. První se pokouší identifikovat parametry filtrovacích algoritmů pomocí algoritmu Expectation-Maximisation, implementací metody maximální věrohodnosti. Druhý přístup je založen na prostých odhadech parametrů normálního rozložení z naměřených a referenčních dat. Nakonec je zkoumána možnost řešení pomocí optimalizačního algoritmu Evoluční strategie. Závěrečné vyhodnocení ukazuje, že třetí přístup je pro daný problém nejvhodnější.
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Jönsson, Pär Göran. "Arc parameters and metal transfer in gas metal arc welding." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12470.
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Mei, Nanxuan. "Characterization of Stainless Steel Welding Fume Particles : Influence of Stainless Steel Grade, Welding Parameters and Particle Size." Thesis, KTH, Materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189203.
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Welding is a widely used method to join two pieces of stainless steel. Since it produces a large amount of fume during the process, it can cause adverse health effects. The welding fume particles contain many elements. Among them Cr, Mn and Ni are of concern. These three elements can cause diseases if inhaled by humans, especially Cr(VI). In this project, welding fume particles are collected during welding of different stainless steel grades (austenitic AISI 304L and duplex LDX2101). Furthermore, different welding types (manual metal arc welding and metal active gas welding), shielding gas (MISON 2, MISON 18 and CORGON 18) and welding electrodes were varied (solid and flux cored wire). The particles were tested by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry and atomic absorption spectroscopy. The composition of the particles was measured and the surface chemical speciation estimated. In addition, metal release (Fe, Cr, Mn, and Ni) in phosphate buffered saline solution (pH 7.4, 37℃, 24h) from the particles was tested. Fe, Cr and Mn were found on the surface of the particles and released to different extent in the phosphate buffered saline solution (dominated by Cr).
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Singh, Anshuman. "Analysis and Design Optimization of Laser Stake Welded Connections." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/SinghA2008.pdf.
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Johansson, Christopher. "Optimization of wall parameters using CFD." Thesis, KTH, Aerodynamik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159875.
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Computational Fluid Dynamics (CFD) is commonly used to calculate the pressure drop in systems with internal ow. To get accurate results the physics of the ow must be well dened together with the right material parameters of the considered geometry. The mate- rial parameter considered in this report is the wall roughness, or sand-grain roughness, and during the thesis work it has been investigated how dierent wall roughnesses aects the pressure drop. It has also been investigated how to set up a CFD simulation to accurately calculate the pressure drop. When setting up a simulation, a good mesh is essential to get accurate results, while using a turbulence model and wall function that is correct for the geometry and physics involved. Pressure drop measurements and the corresponding CAD geometries were available at the start of the thesis work. The simulations were adapted to these to nd the sand-grain roughness for the dierent materials. The main conclusions is that the pressure drop can be accurately calculated when the sand-grain roughness is known and the CFD simulation is well dened. It was found from the mesh sensitivity study that it is essential that the rst cell size is at least twice the size of the sand-grain roughness and that at least two cell layers are used to resolve the turbulent boundary layer.
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Jain, Ruchi V. "Optimization of energy parameters in buildings." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40445.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 34).
When designing buildings, energy analysis is typically done after construction has been completed, but making the design decisions while keeping energy efficiency in mind, is one way to make energy-efficient buildings. The conscious design of building parameters could decrease or completely eliminate the need for Heating, Ventilation and Air Conditioning systems, and thus, optimizing building parameters could help conserve a great amount of energy. This work focuses on two buildings - a passive solar house and an apartment in Beijing. The Beijing apartment is used to study natural ventilation in a space. Both buildings are modeled using EnergyPlus, and analyzed using VBA in Excel. The Genetic Algorithm Optimization Toolbox (GAOT) is used to optimize the parameters for the solar house. The program was run for 150 generations, with there being 20 individuals in each population. The optimized parameters for the solar house resulted in a mean internal temperature of 20.1 C, 7 C lower than that for randomly chosen parameters. The extreme temperatures in both cases were also markedly different, with the optimized parameters providing a more comfortable atmosphere in the house.
(cont.) The apartment parameters were not optimized due to the inherent difficulty in quantifying an objective function. Through the simulation however, it was determined that each window has mass inflow and outflow occurring at the same time. In order to check that mass was conserved through the flow of air in and out of the apartment, the net flow in or out through each window had to be considered. This comparison did show the conservation of mass, which provided confidence in the EnergyPlus model used.
by Ruchi V. Jain.
S.B.
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Weitzel, T. Timothy. "Optimization of sweet sorghum processing parameters." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/80180.
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Production of fuel ethanol from renewable biomass sources has gained popularity in recent years. Sweet sorghum is one of the crops identified as an efficient producer of the sugars needed for ethanol production.
The juice in the sweet sorghum pith contains the greatest proportion of nonstructural carbohydrates, the presumed fermentable material. Sugar cane milling procedures have previously been used to extract the juices from the sweet sorghum plant material.
The research reported herein relates to a new method of juice extraction expected to provide higher juice expression efficiencies than previous methods. The sweet sorghum stalks are chopped and the sugar-laden pith fraction is separated from the fibrous rind-leaf. The pith portion only is then fed through a screw press for juice extraction.
Several chopping and separating parameters were evaluated. A statistical linear regression analysis was employed to evaluate the effects of feed rate, cutting interval, chopper knife speed, and percent of whole stalk mass segregated into the pith category on juice yield.
The analysis revealed that the pith category had the most significant positive effect on juice yield calculated as a percent of whole stalk mass. The highest pith categories provided optimization of juice expression. Feed rate has a negative effect on juice yield, meaning that slower feed rates were better, but this was the least significant parameter. The chopping interval had a positive effect, meaning that the largest value used in the analysis provided for optimum juice yield. The cutting speed parameter has no effect on juice yield.Master of Science
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Ludick, Mark. "Experimental sensitivity analysis of welding parameters during transition from globular to spray metal transfer in gas metal arc welding." Thesis, Peninsula Technikon, 2001. http://hdl.handle.net/20.500.11838/1269.
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Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, Cape Town, 2001Since the discovery of arc welding at the beginning ofthe century, metal transfer has been a topic ofresearch interest. Metal transfer can, in fact be related to weld quality, because it affects the arc stability. Furthermore, it determines the weld spatter, penetration, deposition rate and welding position. Gas Metal Arc Welding (also known as Metal Inert Gas- or MIG welding) is the most co=on method for arc welding steels and aluminurn alloys. Approximately 40% of the production welding in the country is accomplished by this process in which the thermal phenomena and melting ofthe solid electrode are coupled to the plasma arc and the weld pool. Thus the therrno- fluid behaviour of the electrode and detaching drops can have significant effects on the subsequent weld quality and production rate. The knowledge of how metal transfer affects this arc welding process is important for welding control and process automation, as well as in the development of improved welding consumables. Gas metal arc welding has a distinct feature, indicated by the results of Lesnewich [24], [23], that for most gases, there is a discrete metal droplet formation change between low and high current operations. Naturally the droplet size will have a significant influence on the properties ofthe welds. In globular transfer which occurs at low current, the welding electrode melts and produces large droplets (usually larger in diameter than the electrode wire diameter). This mode of transfer is associated with high spatter levels and thus undesirable in terms of welding economics. An increase in welding current will, for most welding! shielding gases, produce metal transfer with smaller droplets, which is termed spray transfer. This mode oftransfer is associated with high voltage and amperage settings, thus producing high deposition rates limited to the flaUhorizontal position.
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Paranhos, R. P. R. "Numerical method for the prediction and optimization of welding procedures." Thesis, Cranfield University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278704.
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Lopes, Thiago Cantos. "Balancing optimization of robotic welding lines: model and case study." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2621.
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FA; UTFPR; RENAULTLinhas robóticas de solda são comuns na indústria automobilística. Durante a produção de um veículo, sua estrutura metálica precisa ser soldada em um único corpo resistente. Isso é feito por meio de centenas de soldas a ponto por resistência, cada uma liga localmente duas ou mais placas metálicas. Distribuir eficientemente esses pontos entre robôs é particularmente desafiador, levando em conta que: cada robôs podem fazer acessar uma parte dos pontos de solda, há tempo de movimentação entre pontos e robôs podem colidir entre si se ocuparem o mesmo espaço físico ao mesmo tempo. Há muitas maneiras factíveis de distribuir pontos de solda. No entanto, cada uma gera um resultado econômico diferente: Se um robô soldar muitos pontos se tornará um gargalo e reduzirá a taxa média de produção.Obter o conjunto de decisões operacionais que gera o melhor desempenho é o objetivo de técnicas de otimização. Há uma ampla variedade de técnicas descritas na literatura de pesquisa operacional e ciência da computação: modelos matemáticos, algoritmos, heurísticas, meta-heurísticas, etc. No contexto industrial, tais técnicas foram adaptadas para diversas variantes de problemas práticos. No entanto, estas adaptações só podem resolver as variantes para as quais foram idealizadas. Se por um lado podem se traçar paralelos entre vários aspectos de linhas robóticas de solda e tais variantes, por outro o conjunto completo de características das linhas estudadas não é tratável por (ou convertível em) nenhuma delas. A presente dissertação desenvolve uma abordagem para otimizar tais linhas, baseada em um modelo de programação linear inteira mista desenvolvido para descrever o problema. Ela também apresenta um estudo de caso para discutir e ilustrar possíveis dificuldades de aplicação e como superá-las. O modelo apresentado foi aplicado a dados de uma linha robótica de solda da fábrica, composta por quarenta e dois robôs, quatro modelos de veículos e mais de setecentos pontos de solda por veículo. A média ponderada da redução em tempo de ciclo obtida pelo modelo foi de 17.5%. Variantes do modelo, concebidas para auxiliar trabalhos futuros, são apresentadas e discutidas.
Robotic welding manufacturing lines are production lines common in automobile industries. During a vehicle's production, the vehicle's metal structure must be welded in a single resistant body. This is made by hundreds of spot-welding points, each of which tie locally two or more metal plates. Efficiently distributing these welding points amongst robots is particularly challenging, taking in account that: not all robots can perform all weld points, robots must move their welding tools between weld points, and robots might interfere with one another if they use the same geometrical space. There are multiple feasible manners to distribute the welding points. However, each of these forms generates different economical results: If a robot performs too many points, it will become a line bottleneck and reduce average throughput. To find the set of operational decisions that yields the best output is the goal of optimization techniques. There are a wide variety of such techniques described in operations research and computer sciences literature: mathematical models, algorithms, heuristics, meta-heuristics, etc. In the industrial context, these techniques were adapted to related line balancing problems. However, these adaptations can only solve the specific variants they were designed to address. While parallels can be drawn between aspects of robotic welding lines and many of such variants, the full combined set of characteristics of the studied lines is not treatable by (or convertible to) any of them. This dissertation develops a framework to optimize such lines, based on mixed-integer linear programing model developed to describe the problem. It also presents a case study to discuss and illustrate possible difficulties and how to overcome them. The presented model was applied to data from the factory's robotic welding lines composed of forty-two robots (divided in thirteen stations), four vehicle models and over seven hundred welding points for each vehicle. The weighted average reduction percentage in cycle time obtained by the model was 17.5%. Model variants, designed to aid further works are presented and discussed.
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Awang, Mokhtar. "The effects of process parameters on steel welding response in curved plates." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2682.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains xiv, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 83-85).
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Titova, Polina. "Optimization of statistical parameters of Eberhard inequality." Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-39641.
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This work is devoted to mathematical modeling of the parameters of the Eberhard inequality using optimization techniques. One of the main purposes of this study is to consider the more general case when the detectors have different efficiencies. In this paper we consider the optimization of parameters for the Eberhard inequality using coefficient of variation taking into account possible errors in the setup of angles during the experiment.
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Hochanadel, Joris Erich. "Effect of Beam Characteristics and Process Parameters on the Penetration and Microstructure of Laser and Electron Beam Welds in Stainless Steel and Titanium." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu160503470688313.
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Pitrun, Miroslav. "The effect of welding parameters on levels of diffusible hydrogen in weld metal deposited using gas shielded rutile flux cored wires." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050202.153920/index.html.
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Gustavsson, Jonas. "Automated Performance Optimization of GSM/EDGE Network Parameters." Thesis, Linköping University, Linköping University, Communication Systems, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-52565.
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The GSM network technology has been developed and improved during several years which have led to an increased complexity. The complexity results in more network parameters and together with different scenarios and situations they form a complex set of configurations. The definition of the network parameters is generally a manual process using static values during test execution. This practice can be costly, difficult and laborious and as the network complexity continues to increase, this problem will continue to grow.This thesis presents an implementation of an automated performance optimization algorithm that utilizes genetic algorithms for optimizing the network parameters. The implementation has been used for proving that the concept of automated optimization is working and most of the work has been carried out in order to use it in practice. The implementation has been applied to the Link Quality Control algorithm and the Improved ACK/NACK feature, which is an apart of GSM EDGE Evolution.
GSM-nätsteknologin har utvecklats och förbättrats under lång tid, vilket har lett till en ökad komplexitet. Denna ökade komplexitet har resulterat i fler nätverksparameterar, tillstånd och standarder. Tillsammans utgör de en komplex uppsättning av olika konfigurationer. Dessa nätverksparameterar har hittills huvudsakligen bestämts med hjälp av en manuell optimeringsprocess. Detta tillvägagångssätt är både dyrt, svårt och tidskrävande och allt eftersom komplexiteten av GSM-näten ökar kommer problemet att bli större.Detta examensarbete presenterar en implementering av en algoritm för automatiserad optimering av prestanda som huvudsakligen använder sig av genetiska algoritmer för att optimera värdet av nätverksparametrarna. Implementeringen har använts för att påvisa att konceptet med en automatiserad optimering fungerar och det mesta av arbetet har utförts för att kunna använda detta i praktiken. Implementeringen har tillämpats på Link Quality Control-algoritmen och Improved ACK/NACK-funktionaliteten, vilket är en del av GSM EDGE Evolution.
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Lin, Wen-Chung, and 林文忠. "Optimization of Welding Process Parameters for Pressure Vessel." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54456664768251465447.
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碩士東南科技大學
防災科技研究所
98
Pressure vessel is considered as one of the dangerous equipment by Taiwan's Labor Safety and Health Law. The dangerous equipment will cause explosion to endangering workers and the public safety if manufactured or used inappropriately. Submerged Arc Welding (SAW) is commonly used in pressure vessel manufacturing. The welding quality will affect greatly to the make use safety of pressure vessel. Taguchi method is one of the most useful tools in experimental design. The method that has been widely used in occasions like less numbers of experiments can handle only single performance characteristic problems. The objective of this paper is to search the optimal welding parameters of SAW that is the most commonly used in the manufacture of pressure vessel by the Taguchi method with Grey relational analysis. The welding parameters (Stick-out, Welding current, Welding voltage, Travel speed) are optimized with considerations of the multiple response performance characteristics (the fusion of root, the face width of weld pool, and the undercut of weld pool).First, the Taguchi’s orthogonal array method which adapts to design an efficient experiment is used to plan the SAW process experiment and welding parameters in layout to reduce the experiment times in this study. In the meantime, the Grey relational grade is also used to find the optimal SAW parameters with the multiple response performance characteristics. The result of the experiment discovered that grey relational grade with the multiple performance characteristics increased from 0.6247 to 0.8042.The improvement percentage of the Grey relational grade is 28.7% that also increased the quality and the safety of pressure vessel. In the future, the dangerous equipment ensures the security of use from the manufacture source. Keywords：Optimization, Taguchi method, Gray relational analysis, submerged arc welding, SAW, Multiple performance characteristics, Dangerous equipment, Pressure vessel
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吳丞宇. "Application of Taguchi method on Parameters Optimization of Flat Welding and Vertical welding in CO2 Welding." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8c86pk.
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碩士國立高雄應用科技大學
機械工程系
105
ABSTRACT The main purpose of this study is to research the optimization of the all-infiltration slotted butt welding of the low-carbon steel plate in CO2 gas Shield Metal Arc Welding, and the welding current (A), welding voltage (V), welding speed (cm / min), wire pro-truding amount (mm) as the main control factor affecting the welding quality, with the Taguchi L9 orthogonal table for welding parameter design, the implementation of nine groups of experiments In order to obtain the tensile strength of the weldment, the objective function of this study is tensile strength. The S / N signal noise ratio is calculated by the large characteristic of Taguchi method. Then, the response table, response graph and variation number (ANOVA) and other methods to find the best combination of welding parameters, the best combination of welding parameters obtained is the combination of A1, B1, C3, D1, that is, welding current: 120 A, welding voltage: 22 V, welding speed 400 mm / min, the protruding amount of wire: 20 mm, in which the contribution rate of welding speed is 68.61%, which is the factor that mainly affects the welding quality characteristic. The welding parameters are A1, B2, C1, D2, that is, welding current: 100 A, welding voltage: 21 V, welding speed 200 mm / min, wire protrusion: 25 mm, in which the contribution rate of welding speed is 59.46%, which Is the main factor affecting the quality characteristics of welding. And then based on the best combination of welding parameters to do further verifica-tion experiments, and finally verify that the optimal weldment tensile strength is better than the previous experiment, and the fracture location is in the base metal area, then the weld penetration and integration is good, (HAZ) of the weldment is less so that a better tensile strength can be obtained, so the combination of this parameter can be defined as a CO2 gas barrier Optimization of welding parameters for metal arc welding. The use of these parameters allows the operating costs and time to be minimized, and increase its competitiveness and timeliness, therefore the engineering design and process improvement could get a great benefit. Keywords：CO2 Gas Shield Metal Arc Welding, Taguchi Method, optimum parameters
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陳奕全. "Study on optimization of fiber laser seam welding process parameters." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/33155008350050138877.
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碩士明新科技大學
精密機電工程研究所
100
This study analyzed variations of shear strength that depend on the fiber laser process during linear welding of AISI 316L stainless thin sheets. The experimental plan was based on a Taguchi orthogonal array table. A hybrid method that includes the response surface methodology (RSM) and back-propagation neural network (BPNN) is proposed to search for an optimal parameter setting of the linear welding process. In addition, an analysis of variance (ANOVA) was implemented to identify significant factors influencing the linear welding process parameters, which was also used to compare the results of BPNN with the RSM approach. The results show that the RSM and BPNN methods are both effective tools for the optimization of linear welding process parameters. A confirmation experiment was also conducted in order to validate the optimal welding process parameter values.
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Tsai, Sheng_Lee, and 蔡勝禮. "The Parameters Optimization on the Laser Welding of Aluminum Alloy." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/11864267467498059232.
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碩士國立交通大學
精密與自動化工程學程碩士班
92
There are several parts of thin metal plates should be welded together in the process of lithium battery manufacturing. These parts are very small and the traditional welding methods were unable to fully satisfy its requirements. Short time, automatic manufacturing and lower power consumption loss are the major characteristics of the pulsed laser welding machine, which is now widely used in many fields. This research studied the optimization of parameters on the laser spot welding of thin plated aluminum alloy’s electrode tab of the lithium battery. The Taguchi experimentation plan method was used to determine the effects of the range of parameters by weld pool depth-width ratio and tensile strength etc. Furthermore, ANOVA (analysis of variance) was utilized to find the quality characteristics of importance in the laser welding parameters build up to the optimum parameters on the laser spot welding. This will be a very important basis for the adjustment of parameters in pulsed laser welding. The material used in this research was thin plate of 3003 aluminum alloy with a thickness of 0.1mm and 0.5mm. The major welding parameters were pulse energy, pulse width, pulse frequency and focus. In this experiment, a 50 watt low power Nd:YAG pulsed laser machine was chosen to do spot welding. The results showed that if the welding parameter is different, the corresponding welding quality is different. For example: The change of the pulse energy factor has a major effect on the tensile strength of the weld pool. However, the pulse width and the pulse frequency have a little effect. Also, when the materials are changed or the dimensional parts are altered, the parameter needs to be readjusted. An interactive relationship between parameters was also found, this relationship; however, require long experimental testing time and valued experience. The method of parameter adjustment is very important. Therefore, it is necessary to build up an effective method plan of experiments to determine optimum parameters of laser welding for mass production.
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Chen, Zhi-Wei, and 陳志瑋. "Study on optimization of fiber laser micro-spot welding process parameters." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/69671088638325831304.
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碩士明新科技大學
精密機電工程研究所
100
This study is applied the experimental method to investigate the optimization of the fiber laser micro-spot welding process parameters. The laser power、processing time、pulse frequency and gas flow were selected for the fiber laser operation process. A preliminary study is used ANSYS results to obtain initial process conditions. The experimental plan was based on a Taguchi orthogonal array table. A hybrid method that includes the response surface methodology (RSM), and back-propagation neural network (BPNN) integrated simulated annealing algorithm (SAA) are proposed to search for an optimal parameter setting of the micro-spot welding process. In addition, an analysis of variance (ANOVA) was implemented to identify significant factors influencing for the micro-spot welding process parameters. The laser power and gas flow is the most significant factor. By regression analysis, a mathematical predictive model fiber laser micro-spot welding process parameters and the tensile strength of the response surface equation were developed in terms of the process parameter. The combining BPNN/SAA optimization method can be obtained for the appropriate combinations of the optimal mixture ratio setting. The result of BPNN integrating SAA was also predictive with BPNN approach. The BPNN prediction models yield smaller average error after training than regression models based on the RSM method. Final, micrographs also show that the appropriate setting of the laser power, befitting the penetration depth and welding of the fusion zone sections were produced.
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Cun-Rong, Hong, and 洪村榮. "Optimization of Welding Parameters for Repair of Ni-based Superalloy Blades." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/29210009983119426612.
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碩士國立彰化師範大學
機電工程學系
91
In this study, finite element method and Taguchi method are used to find the optimum parameters of the repair welding technology. In experimental study, the plasma arc welding is used to weld inconel 738LC base metal. These parameters are current, welding speed, preheating temperature and constraint. A finite element software called as MARC is used for numerical simulation. During numerical simulation process, the quasi-stationary couple thermo-elastic-plastic theory is assumed. The finite element method will be used to analyze the thermal and residual stresses during welding process. An experiment will be done after analyze for identification of numerical results. During welding, the thermal cycle of different locations in weldment will be recorded to compare the temperature field obtained by finite element method. The residual stresses are determined by using the hole-drilling strain-gage method of ASTM standard E837.The study results showed that the most effect factor is current, and the lest effect factor is preheating temperature by Taguchi method. The thermal stress which is more than 900 MPa result in hot crack. In the optimum parameters, the biggest longitudinal residual stress is 832MPa tension stress at the weldment, and the biggest longitudinal hot stress is 721MPa tension stress at the weldment. During repairing process in the Ni-base superalloy blade, the longitudinal thermal stress in the weldment is 680 MPa behind the arc 10 to 25 mm, and the transverse thermal stress in the weldment is 491MPa behind the arc 10 to 25mm.It is the compressive thermal stress where far from both sides of weldment. The higher welding speed, the preheat temperature and lower current result in lower thermal stress and residual stress.
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Hsu, Da-Chung, and 徐大中. "Investigation on the Optimization Model Parameters basic on Nd:YAG Laser Welding Stainless Steel." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/89571390641380981203.
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碩士國立屏東科技大學
機械工程系
92
The purpose of this study is to investigate the characteristics of tensile strength, fusion width and weld under-cut in laser welding AISI304 stainless steel by Nd:YAG, and construct an optimized model for multiple quality objectives. Research procedure can be divided into experimental work, and analysis for single and multiple quality objectives. Firstly, a orthogonal array of Taguchi method is used to arrange experimental work. The laser welding parameters selected include peak power, impulse width, impulse frequency, focusing point, gas pressure and welding speed. The welding qualities of tensile strength, fusion width and weld under-cut are measured then, the optimum laser welding parameters for the single objective of welding qualities can be found by using Taguchi method, respectively. Furthermore, combining these three welding qualities as the multiple objectives to find the optimum laser welding parameters can be conducted by incorporating Taguchi method and grey relational analysis. The results of analysis show that the tensile strength is 89% of the raw material, fusion width is 679 micrometer and weld under-cut is 63 micrometer in the single objective analysis by using Taguchi method, respectively. The tensile strength is 79% of the raw material, fusion width is 730 micrometer and weld under-cut is 49 micrometer in the multiple objective by using Taguchi method. Finally, after introducing grey relational analysis, it can be found that the tensile strength is 63% of the raw material, fusion width is 630 micrometer and weld under-cut is 351 micrometer in the orthogonal array. The tensile strength is 80% of the raw material, fusion width is 628 micrometer and weld under-cut is 23 micrometer out of the orthogonal array, respectively. It can be seen that the last model can obtain the optimum results. Obviously, these three optimized models are good enough for the relational research in laser welding and can be used for practical applications in related industry.
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Yang, Chen, and 楊振. "The Parameter Optimization of Submerged Arc Welding for." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/43421270407299276856.
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碩士國立台灣工業技術學院
機械工程技術研究所
85
The Tuguchi orthogonal array with the AIM network was used to find the parameter conforming the request quality for the reclamation of the steel mill rolls. The 420 stainless steel was applied as filler materials by submerged arc hardfacing. The result shows that there is a minimum wear rate when the slide speed was 2m/sec. The primary wear mechanism with the 2m/sec silde speed is oxidative wear. The primary wear mechanism with the speed over 2m/sec is abrasive wear. The polarization curves wear measured by potentiodynamic polarization. The result shows that the welding current during hardfacing was the major factor to improve the corrosion resistance for 420 stainless steel in 1N H2SO4 solution.
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Ye, Jine-wei, and 葉建偉. "Optimizating Resistance Spot Welding Parameters for Dissimilar Metals Joints." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/umzbk3.
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碩士國立虎尾科技大學
材料科學與綠色能源工程研究所
102
The main purpose of this study is use duplex stainless steel (SAF 2507) and nickel-base superalloys (Inconel 600) to find the optimizing the quality in DC power supply for resistance spot welding. the chrome zirconium copper alloy for the electrode tip material plane electrode, and shear strength as a quality spot welding pieces of property evaluation, in order to obtain the most efficient process of this good parameter values, this study Taguchi method (Taguchi Method), with the impact of the four factors that control the charging voltage、welding time、electrode force and electrode tip size to optimize the process parameters, and through variance analysis (ANOVA) to find out the degree of influence of each parameter on the manufacturing process. Experimental results show that the best combination of parameters is A1B3C1D1, the parameters are 300 V in charging voltage, 4 sec in welding time, 4 kg in electrode force and 4 mm in electrode tip size, this parameter has a higher average shear strength, and in the analysis of variance can be get the electrode head size factor greatest impact on the manufacturing process, the contribution value of 64.8%.
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Feng, Chien-Cheng, and 馮建程. "The optimization of parameters for the Nd:YAG laser welding on the ferrite stainless steel 439." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/02882426903472763909.
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碩士國立屏東科技大學
機械工程系所
99
This study is focused on the use of Nd: YAG laser for 439 ferrite stainless steel sheet in butt welding process, such that the effect of each laser welding parameter for the tensile strength and the weld hardness are investigated. Then two single and a multiple optimization models are established. An experimental work is associated with those optimization models in this study. Firstly, an orthogonal array of Taguchi method is used arrange experimental tests. The selected laser welding parameters are peak power, pulse frequency, pulse width and welding speed. Tensile strength and hardness of the weld parts are measured. The average and variance analysis of the Taguchi method are adopted in order to identify the most important laser welding parameter and the best combination of laser welding parameters. A gray relational analysis is used in order to find the optimized parameters combination in a multiple model. The results showed that in the single objective 99.2% in tensile strength can be obtained and 99.1% in weld metal hardness is achieved. In order to ensure accuracy of the analysis Taguchi method, associated with Gray relational analysis for the multiple objective to find the optimization parameters, has been performed and compared with the single objective model results. At the same time the trends for the relationship between hardness and tensile strength of the weld is developed. As a result, the related process can provide a more convenient mode of quality control inspection.
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Huang, Tai-Hsun, and 黃泰勳. "Optimization of TIG-Flux Welding Process Parameters for Joining of Carbon Steel and Stainless Steel." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/24399960604993867568.
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碩士國立交通大學
工學院碩士在職專班精密與自動化工程學程
94
The purpose of this study is to explore and discuss the optimization of TIG-Flux welding process parameter for joining of low-carbon steel SAE1020 and stainless steel AISI304. The mixed oxide powder of titanium dioxide (TiO2) and silicon dioxide (SiO2) was used as maximum efficiency flux during tungsten inert gas (TIG) welding process. In this study, the depth/width ratio of weld pool geometry is selected to be the quality characteristics. Taguchi methods is used to determine the optimal conditions of those factors effectively, such as the angle of tungsten electrode tip, welding current, travel speed of the welding torch and blending proportion of flux powder. From the results of Taguchi Methods experiment, the optimal welding parameters for joining of the SAE1020 carbon steel and the AISI304 austenitic stainless steel are (1) tungsten electrode tip angle of 60 degree; (2) welding current of 180Amp; (3) welding torch travel speed of 150 mm/min; and (4) mixed powder combination of 20% titanium dioxide and 80% silicon dioxide. Besides, from the results of analysis of variance (ANOVA), the orders of the importance on the depth/width ratio of weld pool geometry within the four control factors are (1) combination of mixed powder; (2) travel speed of welding torch; (3) welding current; and (4) angle of electrode tip.
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Chang, Ya-Ting, and 張雅婷. "An Evolutionary Taguchi Experimental Method for the Optimization of Welding Parameters for Aluminum-Magnesium Alloy Materials." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/98008857782025702912.
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碩士華梵大學
工業工程與經營資訊學系碩士班
96
Although aluminum-magnesium alloy materials possess many superior mechanical characteristics, the suitable range of their welding parameters is quite narrow such that the optimal parameter design becomes a challenge to relevant industries under time and cost restraints. Generally, it is very difficult to create a formula to determine the relationship between welding parameters and quality performance, which is usually learned from knowledge and experience of specialists. Thus, repetitive training and learning processes without effectiveness and efficiency are required in the conventional welding industry, especially, for the tasks beyond the knowledge and experience of the specialists. This research aims to develop an economic and effective experimental design method for handling design of experimental problems involving a large number of numerical parameters and levels. The proposed research method integrates genetic algorithm, artificial neural network and Design Of Experiment(DOE) techniques for comprehensively and objectively searching and evaluating potential parameter combinations. This method enables solving the DOE problem mentioned in the previous paragraph. The acquirement of the optimal welding parameter combination for magnesium-aluminum alloy materials can significantly improve the quality and efficiency of light industrial products. Developing an Evolutionary Taguchi Experimental Method can really assist to obtain the best parameter design combination and learn the relationship between the welding parameters and quality performance of magnesium-aluminum alloy materials. Furthermore, the learning result is useful for the creation of a parameter setting support system embedded in automatic welding equipments. The result from experiments not only can provide for the welding parameter design for magnesium-aluminum alloy materials, but also it shows that the proposed Neural Network-Genetic Algorithm perform better than the individual Taguchi’ Method. The final result from this research is really worthy to be referred by the researchers and relevant welding processes to promote research and product quality for future competition.
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Wen－Jinn, Huang, and 黃文進. "Optimization of Plasma Arc Welding Parameters by Using the Taguchi Method with the Grey Relational Analysis." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/35233752535037852217.
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碩士國立臺灣科技大學
機械工程系
92
The objective of this paper is to search the optimal plasma arc welding（PAW）process parameters by the Taguchi method with Grey relational analysis. First ,the Taguchi’s ortho- gonal array method which adapts to design an efficient experiment is used to plane the plasma arc welding experi- ment and welding parameters in layout to reduce the experi- ment times in this paper. In the meantime,the Grey relational grade is also used to find the optimal plasma arc welding parameters with the multiple response performance characteris- tics.The welding parameters (welding current,welding speed, plasma gas flow rate,and torch stand-off) are optimized with considerations of the multiple response performance charac-teristics(the penetration of root,the face width of weld pool, and the undercut of weld pool).As a result,the improve percentage of the Grey relational grade with the multiple per- formance characteristics is 35.4% .It is obviously increased from 0.645 to 0.874 after using the optimal welding parameters for PAW.Finally ,it is clearly shown that the multiple response performance characteristics are greatly improved through this study.
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Wu, Cheng-Hung, and 吳政鴻. "Application of Taguchi Method for optimization of Process Parameters with Fiber Laser Welding on Stainless Steel Sheet." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/62px3a.
Full textAbstract:
碩士國立高雄應用科技大學
機械工程系
105
ABSTRACT High-power fiber laser provides excellent beam performance, resulting in its weld- ing, cutting, marking, drilling and precision machining and other fine laser processing applications are difficult to compete. Optical fiber laser is lightweight, compact and have long life advantages, also it has small spot size with high energy density charac- teristics, which is very suitable for welding small parts. In this thesis, 200W fiber laser was used for stacking welding. Both 300 μm and 300 μm stainless steel sheets were used as test material. The L9 (34 ) orthogonal table experiment was combined with four control factors (pulse width, power , laser focus and N2 flow rate) with high、medium、 low levels to sort the experiment for the relationship between the factors and welding thrust. The combination of the optimization parameters during maximum welding thrust is obtained by the combination of the quality characteristics and the response table. The ANOVA analysis shows that the contribution of the main factors when the push force is the highest during pulse width is 51.76%, and laser power of 40.9%. The best com- bination of parameters is pulse width: 19000 μs, power: 170 Watt, The laser focus of 185 mm and N2 gas supply 100 LPM. Resulting with best average push force is 39.889 Keywords: fiber laser, laser welding, spot welding
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Su, Ping-Hua, and 蘇炳華. "Friction Stir Spot Welding Parameters Optimization of Aluminum Alloy Sheets and Plated Steel Sheets Using Taguchi Method." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/49872882830302330268.
Full textAbstract:
碩士國立高雄應用科技大學
機械與精密工程研究所
103
In this research, friction stir spot welding (FSSW) is applied to dissimilar metal join and also studies the influence of welding parameters for mechanical properties. The selection of welding parameters includes tool rotation, hold time of spot welding, tool plunge depth , then they are evaluated by using the results of tensile test. The L9 orthogonal table of Taguchi Method is used in this work. It predicts the optimal welding parameterswithanalyzing the S/N ratio and ANOVA;meanwhile, the neural networks and genetic algorithms also is applied to predict the optimization parameters of FSSW. Taguchi Method compares with neural networks using genetic algorithms and these results are different. The experimental results optimizedto obtain optimal parameters by neural networks with genetic algorithms are better than the optimal parameters of Taguchi Method.
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廖桂毅. "The parameter optimization of laser welding for Ti-6Al-4V alloy." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/20435012170122175752.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
89
The compromise programing with the AIM network was applied to find the optimal parameters of laser welding for Ti-6Al-4V alloy sheets in this study.Furthermore,the Taguchi methode was used to analyze the effects of laser welding parameters on the shape and contour of laser welds.The butt welds were made in titanium alloy sheets of 2.5 mm thickness by CO2 laser.The micro-hardness test,bending test,optical microscope and scanning electron microscope examination were used to evaluate the relationship between laser welding parameters and mechanical properties.The study concluded that no significant change in mechanical properties was found within the laser power ranges from 2.4KW to 3.0KW and welding speed ranges from 1400 mm/min to 2000 mm/min.The root openings of welds were the major welding parameter to affect the quality of welds.
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LIN, KAO-LI, and 林高立. "Optimization Analysis of Welding Parameter for Duplex Stainless Steel with GTAW." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/g7443z.
Full textAbstract:
碩士國立高雄應用科技大學
機械工程系
106
This dissertation presents the results of using the Taguchi method to search for optimal parameters for gas tungsten arc welding (GTAW) of S32205 duplex stainless steel. These findings help optimize the effectiveness of the welding process. Duplex stainless steel with a 30% to 70% balance of ferrite to austenite exhibits an excellent combination of high tensile strength, high toughness, and good corrosion resistance. In order to obtain a finished product after welding that still retains the base material properties of duplex stainless steel, the fishbone diagram method (one of the six quality assurance practices) is used to perform the initial selection of control factors and associated conditions as the basis for analysis and control of the welding experiment. In the experimental process, the L_9 (3^4) orthogonal table was used for parameter design. Four factors were used as control factors: welding wattage, welding speed, inert gas flow rate, and inert gas mixing ratio. Each factor was set to three levels, with GTAW performed on test pieces of duplex stainless steel. Each test piece was tested by a laboratory mechanical universal testing machine to obtain the tensile strength data, and a ferrite iron detector was used to obtain the percentage of ferrite iron. The data were imported into the Taguchi method to analyze the contribution of each factor. For tensile strength, the greater the strength the better. For ferrite grain ratio, the more normal the better. The optimized parameter combination was then tested and verified by welding test pieces. When the target function is achieved, we can incorporate the parameters into the welding procedure specification and use linear regression to obtain the best results. The parameters are converted into formulas to predict future welding information. When the company receives new orders in the future that require new welding procedures, the same process can be used to directly set the optimization parameters to complete the welding procedure verification in the shortest possible time. This eliminates trial and error lag time and improves overall work efficiency.
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Cheng, Wang Shih, and 王士誠. "Research on the Optimization Parameters for CO2 Gas Shield Metal Arc Welding of AH32 High Tension Steel Plate." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71059822186398724465.
Full textAbstract:
碩士國立高雄應用科技大學
機械與精密工程研究所
101
The welding mechanical properties and strength as well as both the welding efficiency and quality are be affected by the welding parameters and base materials. Therefore, this thesis aims to investigate the optimal parameters for CO2 gas shield metal arc welding process of AH32 high tension steel plate. The welding current, the welding voltage, the welding speed, and the distance between the welding wire and the base material are the main factors affecting the welding tensile strength, which was considered as an objective function. In order to obtain the good strength, Taguchi method was used to find the best parameters combination. First of all, with the Taguchi method, an orthogonal array L9 was used to conduct welding parameter designs and nine experiments. Next, analysis of variance (ANOVA) employed to find the most significant parameter. Final, based on the optimized parameters, a tensile test was conducted to verify the welding strength. The results showed that the optimal parameters are the welding current, I, at level 2 of 210 A, the welding voltage, II, at level 2 of 30 V, the welding speed, III, at level 1 of 30 cm/min, and the distance between the welding wire and the base material, IV, at level 1 of 15 mm. Of these parameters, ANOVA results showed that the welding speed is the most significant parameter with contribution of 40.43 %. The results concluded that the optimized tensile strength is better than that of the previous experiments. Besides, the positions of the fracture zones are on the base material. It reveals that there are good welding penetration and fusion, i.e. no severe pores, cracks and defects such as slag and heat affected zone (HAZ), which less influence on the tensile strength. Therefore, the tensile strength was improved better and time-costing was also decreased effectively.
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Kumar, K. "Studies On Friction Stir Welding Of Precipitation Hardenable Aluminium Alloys." Thesis, 2009. http://hdl.handle.net/2005/720.
Full textAbstract:
Friction Stir Welding (FSW) is an emerging solid state welding process. It has been a proven method for welding high strength aluminium alloys which were previously not recommended for conventional fusion welding. Since the invention of the process by The Welding Institute, United Kingdom, in 1991, a number of studies have been conducted on the material flow, microstructural evolution and mechanical properties of friction stir welds. However, there is not enough conceptual background available on FSW process for physical understanding of the mechanism of weld formation. In addition to that, FSW welds of high strength precipitation hardenable aluminium alloys suffer from reduced joint efficiency due to overaging in the heat affected zone. In the present investigation, experimental analysis has been carried out to understand the mechanism of weld formation and parameter optimization for aluminium alloys 7020-T6 and 6061-T6. For this purpose the investigations have been made on both the process aspects and the material aspects.
The process aspects are analyzed with the objective of learning the mechanism to produce defect free welds. For this purpose experiments have been carried out to analyze the effect of FSW parameters, material flow and the frictional characteristics between the tool and base metal. Preliminary experiments are conducted on aluminium alloy 7020-T6 with different tool geometries to analyze the interaction of the tool with the base metal using a knee-type vertical milling machine. Then, the tool geometry which produced defect-free weld is used for further experimentation. The role of tool pin, shoulder and axial load on the formation of defect free weld is analyzed in an innovative experiment, where the tool and base metal interaction is continuously increased by continuously increasing the interference between the tool and base metal. In another experiment the initial abutting interface position with respect to the tool is continuously varied to study the interaction of the tool with the initial interface and to find the positional information where the initial interface is completely eliminated. Further, the tool metal interface condition is studied using a specially designed tribological experiment which simulates the FSW condition.
From the base metal point of view, due to the strain, strain rate and temperature imposed on the base metal during the process, the microstructure is altered. In precipitation hardenable aluminium alloys the strengthening precipitates are dissolved or overaged in the weld region depending on the peak temperature in the region, which reduces the joint efficiency. However, the dissolution and overaging are kinetic process. In order to analyze this time dependant softening behavior of the base metal 7020-T6 and 6061-T6, isothermal annealing and differential scanning calorimetric studies are performed.
In order to obtain FSW welds with maximum joint efficiency, the welding temperature should not exceed the “softening temperature” of the base metal. But, to produce defect free welds favorable material flow in the weld nugget is necessary. The material flow and consolidation depend on the process temperature. Hence, for a given tool to produce defect free weld there is a need for minimum temperature. If the weld formation temperature is less than the base metal softening temperature, the weld can be made with 100% joint efficiency. In order to optimize the FSW parameter which gives defect free weld with lowest possible temperature, an instrumented programmable FSW machine is designed and developed. The machine is designed in such a way that welding parameters – rotation speed, traverse speed and plunging depth – can be continuously varied from the start to end of the weld between given two values. This reduces the number of experimental trials, material and time.
Based on the experimental results the following conclusions are derived.
1.The minimum diameter of the pin required for FSW depends on the base metal and tool material property for a given set of parameters. If the pin diameter is insufficient for a given set of welding parameters, it fails during plunging operation itself.
2.There is a minimum diameter of the shoulder for a given diameter of the pin which produces defect free weld. The ratio of pin to shoulder to produce a defect free weld is not a constant value. It changes with tool geometry and process parameters.
3.Increasing the area of contact between the tool and shoulder for a given set of parameters increases the heat input and results in increased weld nugget grain size.
4.Initial abutting interface of the base metal is eliminated at the leading edge of the tool. However, new surfaces are generated due to interaction with the tool and the newer surfaces are consolidated at the trailing edge of the tool. Importantly, the weld strength is controlled by the defects generated due the improper elimination of newly generated surfaces.
5.Optimal axial load is required to generate the required pressure to consolidate the transferred material at the trailing edge of the tool and should be equal to the flow stress of the material at the processing temperature. The optimal axial load is 8.1kN for a tool having 20mm diameter shoulder with 6mm diameter frustum shaped pin.
6.Only the material that approaches the tool at the leading edge on the advancing side is stirred and the remaining material is simply extruded around the tool. Further, the initial abutting interface is completely removed only when it is located in the stirring zone, otherwise the initial abutting interface is not eliminated. In the present study the interface is completely stirred when it is located on the advancing side of the tool between 0.5mm away from the centerline and edge of the tool.
7.The temperature and pressure at the tool–base metal interface is above the temperature and pressure required for seizure to occur for given tool material (H13) and base metal (7020-T6). Hence, it is clear that during FSW the base metal transfers on to the tool and interaction occurs between transferred layer on tool and base metal. The coefficient of friction between the given tool material and base metal in FSW condition is in the range of 1.2 – 1.4.
8.The minimum temperature requirement for FSW of 7020-T6 is 400oC and 6061-T6 is 430oC. However, 7020-T6 and 6061-T6 softens at lower temperatures than that of the minimum FSW temperature. 7020-T6 softens 30% in 7min at 250oC, 4min at 300oC, 2min at 350oC and 1min at 400oC. After softening 30%, there is 10% recovery in hardness and the hardness remains constant thereafter. Whereas 6061-T6 softens gradually up to 47% in 7min at 350oC and 400oC, below the temperature of 250oC for 7020-T6 and 350oC for 6061-T6 there is no softening observed in 7min.
9.The maximum joint efficiency of the 7020-T6 weld is 82% and 6061-T6 weld is 60%.
10. The reduction in joint efficiency is attributed to overaging of the material in the heat affected zone.