Academic literature on the topic 'Software prototyping][Linear life cycle models'
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Journal articles on the topic "Software prototyping][Linear life cycle models"
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Wilson, Michael, David Duce, and Dan Simpson. "Life cycles in software and knowledge engineering: a comparative review." Knowledge Engineering Review 4, no. 3 (1989): 189–204. http://dx.doi.org/10.1017/s0269888900005026.
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AbstractProgress in software engineering has led to system development following models of the system life cycle. These models incorporate the use of prototyping and formal methods of program verification. They are becoming supported by integrated project support environments and permit the planning and monitoring of software development projects.In contrast, knowledge based systems (KBS) are developed using informal views of the system life cycle. Tools have been developed to support some stages of the life cycle in an undisciplined manner. The commercial use of KBS needs development projects to be planned and monitored. This requires methods and tools based on systematic life cycle models to be established for KBS.This paper reviews the current state of life cycle approaches to software engineering and KBS development projects in order to provide a direction for the development of methodical KBS life cycle models.
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Petrov, Dmitriy Nikiforovich, and Tamara Balabekovna Chistyakova. "SYSTEM OF AUTOMATED DESIGN AND PROTOTYPING OF SYNTHESIS SITES OF CARBON NANOCLUSTER STRUCTURES." Vestnik of Astrakhan State Technical University. Series: Management, computer science and informatics 2021, no. 3 (2021): 16–27. http://dx.doi.org/10.24143/2072-9502-2021-3-16-27.
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The article focuses on using the integrated multi-component computer-aided design and control systems, which changes the product life cycle processes in the high-tech complex chemical and technological systems. In the integrated design of production facilities, special attention is paid to safety, productivity, reliability, ergonomics of the production line and the material and technical environment. The most effective in project management are flexible life cycle models that connect diverse specialists in a single information environment. The relevance of the task of developing and implementing problem-oriented heterogeneous computer-aided design and digital prototyping systems is justified. There is described a method for improving the efficiency of designing production facilities while minimizing the time required preparing a design solution, and the risks of design errors caused by the communication dissonance of diverse specialists. The architecture of the computer-aided design and digital prototyping system with a description of its basic components is presented. The creation of a digital model of the design object is described on the example of the reactor site and the material and technical base of the process of synthesis of carbon nanocluster structures that are in high demand in various industries. The conducted tests and the introduction of the resulting applied software solution into the educational process proved its efficiency in solving problems of integrated computer-aided design and digital modeling not only of objects of the carbon nanoindustry, but also for other industries with a similar material and technical base.
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Alqahtani, Ayedh, and Andrew Whyte. "Artificial neural networks incorporating cost significant Items towards enhancing estimation for (life-cycle) costing of construction projects." Construction Economics and Building 13, no. 3 (2013): 51–64. http://dx.doi.org/10.5130/ajceb.v13i3.3363.
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Industrial application of life-cycle cost analysis (LCCA) is somewhat limited, with techniques deemed overly theoretical, resulting in a reluctance to realise (and pass onto the client) the advantages to be gained from objective (LCCA) comparison of (sub)component material specifications. To address the need for a user-friendly structured approach to facilitate complex processing, the work described here develops a new, accessible framework for LCCA of construction projects; it acknowledges Artificial Neural Networks (ANNs) to compute the whole-cost(s) of construction and uses the concept of cost significant items (CSI) to identify the main cost factors affecting the accuracy of estimation. ANNs is a powerful means to handle non-linear problems and subsequently map between complex input/output data, address uncertainties. A case study documenting 20 building projects was used to test the framework and estimate total running costs accurately. Two methods were used to develop a neural network model; firstly a back-propagation method was adopted (using MATLAB SOFTWARE); and secondly, spread-sheet optimisation was conducted (using Microsoft Excel Solver). The best network was established as consisting of 19 hidden nodes, with the tangent sigmoid used as a transfer function of NNs model for both methods. The results find that in both neural network models, the accuracy of the developed NNs model is 1% (via Excel-solver) and 2% (via back-propagation) respectively.
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Chugunov, Mikhail V., Irina N. Polunina, and Anton M. Pjanzin. "E-Tricycle Vehicle Design Based on Parametric CAD/CAE Models." Engineering Technologies and Systems 30, no. 3 (2020): 464–79. http://dx.doi.org/10.15507/2658-4123.030.202003.464-479.
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Introduction. National Technology Initiatives (STI), designed to develop and implement High-Tech tools into engineering practice and based on the Industry 4.0 concept, require appropriate technical solutions for all phases of the product lifecycle from design to disposal. Implementation of the concept involves the formation of technological groups and markets in different directions in particular one of the emerging markets of STI is Auto.Net. At the same time, the product design stage is basic and should be implemented in a form ensuring the entire life cycle of the product on the principles of this concept. Materials and Methods.The article presents the methodology and results of designing an electric vehicle-tricycle in the integrated CAD/CAE systems. The design process is the development of digital parametric models of different types and levels on a top-down and bottom-up basis. The parametric properties of models provide the ability to develop design solutions efficiently, including design, analysis and optimization. The design solutions are developed in the CAD/CAE/CAM/PDM/PLM SolidWorks (Motion, Simulation) software. Results. The results of the study are rational design paths for the structures of the class under consideration in the SolidWorks software, as well as design solution of the electric tricycle-vehicle in the form of a system of integrated parametric models, including 3D models of parts and assemblies, models of solid-state mechanics, finite-element models for solving problems of mechanics of the deformed solid body in the form of linear and non-linear statics, linear dynamics, parametric optimization. Videos of the results are provided for illustrative purposes. Discussion and Conclusion. In the research, the design trajectory of the electric vehicletricycle based on correct formulation for the design problems and providing the rational choice of means, tools, and technologies from basic SolidWorks functionality is presented. The trajectory provides both an efficient solution to design problems and an assessment of the adequacy of the results obtained. In terms of the possible perspective of this work, it is necessary to specify the solution of optimization tasks according to various criteria of project efficiency and the development of an integrated (cyber-physical) model of electric vehicle-tricycle, which meets the requirements of digital twins. At the same time, bidirectional associative links between virtual and physical components of the integrated model will solve a number of additional problems: control of the accuracy of digital models, giving the digital model synergistic properties, planning of the trajectory and unmanned control on the principles of IoT (Internet of Things).
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Venghiac, Vasile Mircea, Cerasela Panseluţa Olariu, and Mihai Budescu. "Structural Rehabilitation Analyses for a Romanian Cultural Heritage Building Located in Seismic Area." Advanced Engineering Forum 21 (March 2017): 196–203. http://dx.doi.org/10.4028/www.scientific.net/aef.21.196.
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Structural rehabilitation, especially of historical monuments, is a difficult and widely treated subject in order to achieve a better insight regarding their seismic response. In Romania, a lot of historical monuments that require rehabilitation due to seismic actions are encountered. This paper aims to assess the effects of structural retrofitting on a historical monument located in Botoşani County, which withstood during its life cycle important earthquakes. The 20th century monument is located in a seismic active area of North – Eastern Romania, at a distance less than 300 km from Vrancea region where the epicenter of major earthquakes for the Eastern Europe is situated. Two hypotheses for the FE model of the structure were considered, namely with and without the rehabilitation solution. Nonlinear FEM analyses were performed in computer software environments. Using specific modeling tools of the computer program it is intended to simulate linear behaviour of masonry and global response of the structure. Comparisons between the two models were made. The results are used to validate the rehabilitation solution also consisting a source of information for its effects during structural lifetime cycle of the historical church.
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Budko, T. G., and L. І. Lavrinenko. "BIM-TECHNOLOGY METHOD AND MODELS IN THE DESIGN OF THE AQUAPARK DOME STRUCTURE WITH WOODEN ARCHES." Modern structures of metal and wood, no. 25 (August 2021): 72–84. http://dx.doi.org/10.31650/2707-3068-2021-25-72-84.
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Тhe issues of designing a multi-volume dome structure for a water park using wooden arches as load-bearing structures are сonsidered. The complexity of the volumes and their joining lines, as well as the requirement to perform non-linear analysis of large-span timber elements at the request of Eurocode 5, make an information model with elements of BIM-technology necessary. It is noted that design using this technology is developing in the direction of taking into account all stages of the structure life cycle. Wood Information modeling is the most prepared for the use of BIM-technologies. This is due to the high factory readiness and complex digital technologies for the manufacture of modern wooden structures elements. During the design, an information model was formulated in the SAPFIR software package with the subsequent possibility of importing the model into the LIRA-SAPR software package. Additional steps were used to build the model: creating a 2D template in AutoCad with reference lines and the location of rigid walls on which the coating rests, and importing drawings into SAPFIR as a dxf-underlay; for all elements of the system located in the local coordinate system, auxiliary lines were built for the correct orientation of the plane in space; loads on curved surfaces were calculated in the PC Expri. For the further development of the nodes, 3D modeling was used with the transfer of the information model to the Tekla Structures PC as a specialized environment for the constructive section of the project. The presented calculation of a complex dome structure using wooden arches summarizes the approaches to the development of unique forms of structures using wood. The use of information models made it possible to reduce the time spent on design, to optimize the drawings, and also to significantly increase the complexity of the architectural and structural design of the structure and the design model, taking into account the nonlinear effects of wood.
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Azrag, A. G. A., A. A. Yusuf, C. W. W. Pirk, S. Niassy, K. K. Mbugua, and R. Babin. "Temperature-dependent development and survival of immature stages of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae)." Bulletin of Entomological Research 110, no. 2 (2019): 207–18. http://dx.doi.org/10.1017/s0007485319000476.
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AbstractAlthough the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) is the most destructive insect pest of coffee worldwide, there is much to learn about its thermal biology. This study aimed to develop temperature-based models for H. hampei development and to provide the thermal requirements of immature stages in the laboratory. Using a new observation method, larval development and survival were monitored daily on fresh Arabica coffee seeds, under seven constant temperatures in the range 15–35°C, with 80 ± 5% RH and 12:12 L:D photoperiod. Linear and non-linear functions were fitted to the development data plotted against temperature, using Insect Life Cycle Modelling software (ILCYM). Temperature significantly affected the development time of all immature stages. Egg incubation period ranged 4.6–16.8 days, under temperature between 30 and 15°C. No development occurred at 35°C and the larval stage did not develop to pupa at 15°C. The minimum temperature threshold (Tmin) estimated from linear regression was 10.5, 13.0, 15.0 and 13.0°C, for egg, larva, pupa and the total development from egg to adult, respectively. The maximum temperature threshold (Tmax) estimated from the Sharpe and DeMichele function was 32°C for egg to adult development. The thermal constant (k) was estimated at 78.1, 188.7, 36.5 and 312.5 degree days, for egg, larva, pupa and for egg to adult, respectively. Our results will help understand and predict the pest population dynamics and distribution in coffee plantations as impacted by temperature, and as such, will contribute to a more efficient management of the pest.
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Khadioli, N., Z. E. H. Tonnang, E. Muchugu, et al. "Effect of temperature on the phenology ofChilo partellus(Swinhoe) (Lepidoptera, Crambidae); simulation and visualization of the potential future distribution ofC. partellusin Africa under warmer temperatures through the development of life-table parameters." Bulletin of Entomological Research 104, no. 6 (2014): 809–22. http://dx.doi.org/10.1017/s0007485314000601.
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AbstractMaize (Zea mays) is a major staple food in Africa. However, maize production is severely reduced by damage caused by feeding lepidopteran pests. In East and Southern Africa,Chilo partellusis one of the most damaging cereal stem borers mainly found in the warmer lowland areas. In this study, it was hypothesized that the future distribution and abundance ofC. partellusmay be affected greatly by the current global warming. The temperature-dependent population growth potential ofC. partelluswas studied on artificial diet under laboratory conditions at six constant temperatures (15, 18, 20, 25, 28, 30, 32 and 35 °C), relative humidity of 75±5% and a photoperiod of L12:L12 h. Several non-linear models were fitted to the data to model development time, mortality and reproduction of the insect species. Cohort updating algorithm and rate summation approach were stochastically used for simulating age and stage structure populations and generate life-table parameters. For spatial analysis of the pest risk, three generic risk indices (index of establishment, generation number and activity index) were visualized in the geographical information system component of the advanced Insect Life Cycle modeling (ILCYM) software. To predict the future distribution ofC. partelluswe used the climate change scenario A1B obtained from WorldClim and CCAFS databases. The maps were compared with available data on the current distribution ofC. partellusin Kenya. The results show that the development times of the different stages decreased with increasing temperatures ranging from 18 to 35 °C; at the extreme temperatures, 15 and 38 °C, no egg could hatch and no larvae completed development. The study concludes thatC. partellusmay potentially expands its range into higher altitude areas, highland tropics and moist transitional regions, with the highest maize potential where the species has not been recorded yet. This has serious implication in terms of food security since these areas produce approximately 80% of the total maize in East Africa.
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Alamnie, Mequanent M., and Yalelet Endalemaw. "FATIGUE LIFE ANALYSIS OF RAIL-WELDS USING LINEAR ELASTIC FRACTURE MECHANICS." Proceedings of International Structural Engineering and Construction 6, no. 1 (2019). http://dx.doi.org/10.14455/isec.res.2019.197.
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The initiation and growth of fatigue cracking is mainly due to high stress concentration, heterogeneity and poor quality of weld. The detection and rectification of such weld defects are major concerns of rail network managers to reduce potential risk of rail breaks and derailments. To estimate the fatigue life of welded joints and to analyze the progress of fatigue cracks, a fracture mechanics-based analysis and fatigue models were developed using Finite Element Analysis. The initial flaw is obtained from a sample weld using ultrasonic flaw detecting machine test. Linear Elastic Fracture Mechanics (LEFM) approach based on the Paris law was applied to determine critical crack size and the number of cycles to failure using FRANC3D software. The inspection interval of rail welds before fracture (failure) was suggested based on reliability and life cycle analysis that correspond with minimum overall cost and frequency interval. It is recommended that fracture-based models in combination with reliability analyses can be a sustainable infrastructure decision-making algorithm.
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Rahman, M. M., A. K. Ariffin, N. Jamaludin, and C. H. C. Haron. "Durability Assessment Of A New Free Piston Spark Ignition Linear Engine: A Computational Approach." Jurnal Teknologi, January 20, 2012. http://dx.doi.org/10.11113/jt.v45.318.
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Pendekatan pengkomputeran moden yang berasaskan analisis unsur terhingga untuk penilaian ketahanan dalam komponen enjin linear palam pencucuh piston bebas dua lejang dibentangkan. Maklumat pembebanan adalah sukar ditentukan tanpa sebarang prototaip. Sejarah pembebanan boleh ditentukan menggunakan dinamik multi–jasad. Dengan menggabungkan dinamik multi–jasad, analisis unsur terhingga dan analisis hayat lesu, hayat lesu bagi enjin linear boleh diramal awal semasa reka bentuk. Kertas kerja ini membentangkan ramalan hayat lesu bagi komponen enjin linear piston bebas dengan pembebanan amplitud berubah. Permodelan dan analisis unsur terhingga dijalankan menggunakan reka bentuk terbantu komputer dan perisian analisis unsur terhingga serta ramalan hayat lesu adalah menggunakan kod lesu komersial. Pendekatan permulaan retak digunakan bagi meramal hayat lesu komponen bagi enjin linear piston bebas. Keputusan yang diharapkan adalah plot kontur hayat lesu dan histogram kerosakan pada kes yang paling rosak. Keputusan yang diperolehi menunjukkan bila menggunakan rangkaian beban tegangan yang lebih banyak (beban SAETRN), SWT dan Morrow memberikan hayat lebih singkat daripada model Coffin Manson Walau bagaimanapun, kaedah Coffin–Manson memberikan ramalan yang konservertif bila sejarah masa beban mampatan lebih banyak dan tegasan min sifar. Keputusan juga menunjukkan julat tegasan yang besar juga menyumbang lebih besar kerosakan. Kata kunci: ketahanan, hayat lesu, unsur terhingga, dinamik multi–jasad, enjin linear piston bebas. A modern computational approach based on finite element analysis for integrated durability assessment in a two–stroke free piston spark ignition linear engine components is presented. The loading information is difficult to determine without a prototype. The loading histories can be determined using multi–body dynamics. By combining the multi–body dynamics, finite element analysis and fatigue life analysis, the fatigue life of the linear engine components can be predicted early in the design cycle. This paper presents the prediction of fatigue life for free piston linear engine components with complex variable amplitude loadings. The finite element modeling and analysis has been performed using a computer–aided design and finite element analysis software packages, and the fatigue life prediction was carried out using commercial fatigue codes. Crack initiation approach is applied to predict the fatigue life of the component of a free piston linear engine. The results are expected to show contour plots of fatigue life, and damage histogram at the worst or most damaging case. The obtained results indicate that when using the loading sequences is predominantly tensile in nature (SAETRN loading), the SWT and the Morrow models give shorter life than that results obtained using the Coffin–Manson model. However, the Coffin–Manson method gives conservative prediction when the time histories are predominantly compressive, and zero mean stress loadings. It was also observed that the damage to be generated from the cycles is in the higher stress range. Key words: Durability, fatigue life, finite element, multi–body dynamics, free piston linear engine.
Dissertations / Theses on the topic "Software prototyping][Linear life cycle models"
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Hekmatpour, S. "Formal specification based prototyping." Thesis, Open University, 1987. http://oro.open.ac.uk/57020/.
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Rapid prototyping is an approach to software development which attempts to remedy some of the shortcomings of the linear life cycle model, e.g. its inability to cope with fuzzy requirements and system evolution. This thesis first presents a broad survey of rapid software prototyping. It describes the rationale behind the process, the applications of prototyping, and specific techniques which may be used to achieve them. We then describe a system, called EPROS, together with its methodology, which supports a number of prototyping techniques in a coherent framework. The system is comprehensive in its approach and covers the prototyping and development of both functional and human-computer interface aspects of software systems. The former is based on the execution of VDM-based formal specification notation META-IV; the latter is based on a textual representation of state transition diagrams. Dialogue development is further supported by a rich set of abstractions which allow interaction concepts to be specified and directly executed rather than implemented. EPROS is based on a wide spectrum language which supports the main phases of a software development process, namely specification, design, and implementation. Included in this notation is a meta abstraction facility which facilitates its extension by the programmer. The primary application of EPROS is for evolutionary prototyping, where a system is developed iteratively and gradually from the abstract to the detailed, while it undergoes use and while its capabilities evolve. EPROS copes with all the requirements of evolutionary prototyping, namely rapid development, intermediate deliveries and gradual evolution of the system towards the final product. The thesis also describes a number of case studies where the presented ideas are put in practice, and which provide data in support of the effectiveness of the described system.
Conference papers on the topic "Software prototyping][Linear life cycle models"
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Qidwai, M. A. Siddiq, V. G. DeGiorgi, and S. A. Wimmer. "Numerical Implementation of Nonlinear Piezoelectric Models in Commercially Available Tools." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41299.
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Commercially available finite element programs currently provide only linear piezoelectric models for device analysis, precluding their use in understanding domain-switching based failure mechanisms, and thus, limiting their usefulness in predicting accurate life cycle estimates for devices. This work is an initial attempt to bridge this gap by slightly modifying and implementing an existing macromechanical theoretical framework, which represents a broader class of nonlinear model development, in commercial software. The rate-independent evolution equations of remanent variables in the original model are replaced by their rate-dependent form which better imitates physical reality and facilitate quick implementation. Decoupled ferroelectric and ferroelastic versions of the model have been successfully realized and tested. Ongoing work is focused on incorporating the fully coupled model, which will then be used to simulate switching near cracks in PMN-PT single crystal material.
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Dyer, Zachary, and George C. Altland. "An Application of Metal Plasticity in Finite Element Modeling to Predict the Low-Cycle Fatigue Life of a High-Pressure Steam Turbine Casing." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26140.
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In the current market for large steam turbines, customers increasingly want to aggressively cycle their equipment to accommodate electrical grids that include fluctuating supplies of green energy. Increased and aggressive cycling leads to higher probability of low-cycle-fatigue cracking and provides motivation for the design of new steam turbines that are robust enough to withstand this demanding working environment yet still meet the operational and cost expectations of potential customers. ASME BPVC Section III Subsection NH provides a calculation for fatigue damage assessment using either an elastic method or an inelastic method. This paper describes how the inelastic method can be applied to large steam turbines — calculating low-cycle fatigue damage by using commercial finite element software and plastic material models to directly determine elastic-plastic strains throughout the cycle, rather than approximating them using the results of an elastic analysis. The inelastic method is applied to a steam turbine casing during startup cycles — the total strain through the cycle is calculated directly by the elastic-plastic finite element analysis (FEA) then the delta equivalent total strain is calculated using equations in Subsection NH. For comparison, an elastic method is applied to the same analysis — the maximum elastic stress is calculated by the linear-elastic FEA then the delta equivalent total strain is approximated using Neuber’s rule. The inelastic method calculates a smaller delta equivalent total strain, which leads to significantly increased fatigue life. This more sophisticated method could lead to steam turbine components with less cost, more durability, and better performance. This paper also discusses some issues in using the inelastic method, such as shakedown and ratcheting.
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Åman, Rafael, Heikki Handroos, Hannu Kärkkäinen, Jari Jussila, and Pasi Korkealaakso. "Novel ICT-Enabled Collaborative Design Processes and Tools for Developing Non-Road Mobile Machinery." In ASME/BATH 2015 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/fpmc2015-9571.
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The improvement of the energy efficiency is an important topic for non-road mobile machinery developers and manufacturers. These machines normally use fluid power transmission in drivelines and working actuators. New energy efficient technologies, e.g. a hybrid power transmission with an energy recovery feature, have been introduced. Currently most of the manufacturers are still using conventional technologies in their product development process. Human operators have an effect on the overall efficiency of the machines. Taking into account the human effects is difficult and expensive using the conventional design processes and tools. The objective of this study is to provide international machine manufacturers instrumental, yet novel, community and simulation-based (ICT-enabled) tools/methods for the strategic and cost effective development of their product practices and design processes. The development of models and methods will allow for rapid real-time virtual prototyping of complex machines and machine fleets that operate within a number of worksites or geographical conditions. The introduction of this state-of-the art (and going beyond) advancement in real-time virtual technology, simulation, internet based design technologies and software, cyber-physical and big data processing systems, will present a holistic approach to improve the entire product life. Targeted user groups are manufacturers of non-road mobile machinery (i.e. excavators, wheel loaders, etc.). These machines and production systems share the following key features: 1) They are complex mechatronic systems with several interconnections between hydraulic drives; mechanics, electronics, software and 2) they include autonomous, semiautonomous and human driven operated systems. Methods developed will enable machine manufacturers’ access to technologies that will lead to a more cost effective consumer ordinated, life cycle optimization process. This paper will introduce the method of developing customized products in a fast, agile and networked way that will lead to significantly reduced life-cycle costs.
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Cherukupalli, S. Y. Suresh, Krishna Nelanti, Kamlesh G. Gujar, and John Sunil Palle. "Effective Radiation Modelling Technique for Transient Temperature Prediction of Gas Turbine Components." In ASME 2012 Gas Turbine India Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gtindia2012-9549.
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Gas Turbine engine components like Combustor, Diffuser, and Turbines are subjected to very high temperatures. Predicting accurate temperatures of such components demand accurate Radiation modeling along with Conduction and Convection. Radiation heat transfer modeling is very complex due to non linear dependence on temperature and additional parameters driving the heat transfer like shape factor, emissivity, surface area and absorbtivity of material. The commercial software ANSYS developed various Radiation techniques like ‘Radiation Matrix’, ‘Radiosity’ and ‘Radiation modeling between a surface and a point’. A detailed study has been carried out to compare different Radiation models. The ease of building the model, computational time, accuracy, and limitations are thoroughly examined. It is found that all existing methods have some limitations in accuracy, computational time or system requirements. To overcome some of these limitations, a new technique called ‘Surface Effect Element Method’ is proposed in this paper. This method uses ‘Radiosity’ for the shape factor computation and ‘Radiation modeling between a surface and a point’ for modeling Radiation between two surfaces. The average of one surface temperature is transferred to a single point which in turn is used to model the Radiation to the second surface and the same procedure is repeated for the second surface too. A detailed study is carried out and the proposed technique is compared against the available methods. The new technique enables accurate computation of transient temperatures for gas turbine components leading to accurate life prediction for these components. It is shown that ‘Surface Effect Element Method’ has comparable accuracy but significantly lower cycle time and efforts compared to existing methods.
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Ladani, Leila J., and Omar Rodriguez. "Thermo-Mechanical Reliability of Through Silicon Vias (TSVs) and Solder Interconnects in 3-Dimensional Integrated Circuits." In ASME 2009 InterPACK Conference collocated with the ASME 2009 Summer Heat Transfer Conference and the ASME 2009 3rd International Conference on Energy Sustainability. ASMEDC, 2009. http://dx.doi.org/10.1115/interpack2009-89056.
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3-dimensional integrated circuit (3D IC) is a promising technology in today’s IC packaging industry. Since the technology is in infancy stages, many aspects of this technology are still under heavy investigation. Reliability of through silicon via (TSV) interconnects and interlayer bonding between the silicon layers are issues that become more complicated in 3D ICs due to complexity of the architecture and miniaturized interconnects. Optimizing design of these devices is essential in order to avoid short fatigue life of interconnects. This manuscript addresses the impact of design parameters such as die thickness, TSV diameter, TSV pitch, underfill thickness and underfill properties on thermo-mechanical durability of Direct Chip Attach (DCA) solder joints and TSV interconnects used in a 3D IC packages. A design was proposed where DCA is used to connect 4 layers of ICs and TSVs are used to connect the active layer of the dies to the second silicon layer. Solder joints, as small as 50-micron diameter, were used to attach silicon layers. A numerical experiment is designed to vary design parameters at 3 levels using L9 ortagonal array. A 3-dimensional model of the package was built and model was solved under an accelerated temperature cycle loading. Solder is considered as visco-plastic material and copper interconnects are assumed to follow bilinear isotropic hardening behavior. Two continuum damage models, energy partitioning and Coffin-Manson models, were used to assess the number of cycles to failure for solder joints and TSV copper interconnects respectively. Minitab software was used to analyze the result of experiment. The most influential factors on durability of solder interconnect are found to be underfill properties and height. However, the most influential factor on TSV durability is found to be TSV diameter. A non-linear response was observed for TSV pitch and diameter indicating that the optimum level may be in the range selected.
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Riva, Andrea, Alessio Costa, Dalila Dimaggio, et al. "A Thermo-Mechanical Fatigue Crack Growth Accumulative Model for Gas Turbine Blades and Vanes." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-58053.
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Heavy duty gas turbine blades and vanes are operated at high temperatures and high stresses, condition where several damage mechanisms can simultaneously be present. For example creep, fatigue and oxidation play an important role in the propagation of existing cracks. Crack growth models are employed for assessment criteria, interpretation of the field feedback and non-conformities management and they are required to be as accurate as possible when predicting crack propagation under the combined effect of all the three phenomena. In this work, a Linear Elastic Fracture Mechanics (LEFM) model based on isothermal experimental tests and validated by Thermo-Mechanical-Fatigue Crack Growth tests (TMFCG), is employed to predict crack propagation of a cast Ni-base superalloy used in gas turbine blades and vanes. When calculating the individual propagation fractions of creep and fatigue crack growth, the model accounts for the instantaneous stress state and temperature in transient regime (i.e. a complete cycle of start-up, base-load and shut-down). The loss of γ’- precipitates at the crack tip due to surface oxidation is interpreted as environmental damage fraction. A complete workflow for the systematic use of the approach, comprising an in-house software, has been defined and developed. Stress intensity factors used for LEFM calculations are determined either using tabulated weight functions or with the aid of Finite Element Analysis (FEA). This flexible approach is consistent with the industrial need of a given fracture mechanics calculation, which might require different levels of accuracy and resources/time consumption case by case. The software identifies the fraction of propagation caused by oxidation, creep crack growth or fatigue crack growth. This allows checking the physical realism of the results by comparing to metallographic analysis of fracture surfaces from broken TMFCG test specimen and/or real component damage information from field. Besides, this feature can be helpful to support the engineer in residual life evaluation under damage tolerant approach because it allows the identification of the type of operational regime that minimizes crack propagation. The software also allows the execution of sensitivity analyses via Monte-Carlo calculations, identifying for a given component and operational condition the more relevant calculation inputs. This feature also quantitatively supports the engineers in the identification of the most appropriate safety margins.