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Kutuniva, Kari, Jussi A. Karjalainen, and Kari Mäntyjärvi. "Effect of Convex Sheared Punch Geometry on Cutting Force of Ultra-High-Strength Steel." Key Engineering Materials 504-506 (February 2012): 1359–64. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.1359.
Extremely high strength of the ultra-high-strength steels leads to increased load factors on the tooling machines and punching tools. This experimental study examines how much convex punch geometry affects cutting forces when punching ultra-high-strength steels. Tools used in punching tests were four different convex sheared rooftop punches and one conventional flat end punch, to which rooftop punches were compared to. The material in punching tests was ultra-high-strength steel Ruukki Optim 960 QC, with a thickness of 4 mm. The test material in punching tests was sheared with rooftop punches and a flat end punch and occurred cutting forces were measured. The qualities of punched holes were evaluated visually and the roundness measurements were also performed. The results show that the cutting forces of Optim 960 QC can be reduced radically with optimal convex punch geometry. With using 14-degree shear angle of the punch end, the cutting forces reduced up to 57 % compared to forces of the conventional flat end tool. However, largest tested shear angles caused several negative effects on the cutting quality of the holes and therefore they are not suitable in all applications. Punching tests proved that the cutting clearance had no appreciable effect on cutting forces when punching ultra-high-strength steel. Instead there was a noticeable effect on the quality of the punched hole, especially when large shear angles were used.
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Skipper, William. "Overtime: Punchin' Out with The Mill Hunk Herald." Anthropology of Work Review 12, no. 1 (March 1991): 17–18. http://dx.doi.org/10.1525/awr.1991.12.1.17.
Фролов, Е. А., В. В. Агарков, С. И. Кравченко та С. Г. Ясько. "ИССЛЕДОВАНИЕ ТОЧНОСТИ ДЕТАЛЕЙ, ПОЛУЧАЕМЫХ ПРИ РАЗДЕЛИТЕЛЬНЫХ ОПЕРАЦИЯХ В ПЕРЕНАЛАЖИВАЕМЫХ ШТАМПАХ". Open Information and Computer Integrated Technologies, № 81 (16 листопада 2018): 52–63. http://dx.doi.org/10.32620/oikit.2018.81.06.
To determine the accuracy of the readjustable punches for separating operations (perforation + punching out) of sheet-metal forming, the accuracy parameters were analyzed using the random balance method using the method of experiment planning. Analytical dependencies are obtained to determine the values of deviation of the outer and inner contour dimensions of perforated and punched out sheet parts. From the dependencies obtained, it is possible to estimate and predict the value of deviation in the dimensions of the resulting part at any time during the operation of the punch. Practical recommendations on the calculation of the actuating dimensions of the working elements (stamping punch, matrix) of readjustable punches are offered.
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Lin, Jui Chang, W. S. Lin, and King Sun Lee. "A 3D Virtual FEM and SA Method to Determining the Optimization Clearance for a Punching Die." Key Engineering Materials 419-420 (October 2009): 277–80. http://dx.doi.org/10.4028/www.scientific.net/kem.419-420.277.
This study is subject to 3D virtual simulation and experiment design method application in the optimal clearance design in the 3D shell punched processing. During the simulation stage, the PAM-CRASH and 3D-CAD (Pro/E) system are used to model the punching processing. The results of the punching maximum punched burr from the 3D virtual punching simulation were input to a neural network to establish a model corresponding to the 3D shell punched variables. Once the metal punching control parameters, such as punch/die radius, punch/die clearance, punch cutting angle and different material thickness, were given, the punching processing performance (the punching maximum burr and maximum stress) can be accurately predicted by this developed network. Therefore, in this research, a satisfactory result based on the simulation verification is established.
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Zubauskienė, Donata, and Eugenija Strazdiené. "Effect of Friction in the Punch-to-Specimen Contact Zone Upon the Punching Behaviour of Synthetic Leathers." Fibres and Textiles in Eastern Europe 25 (June 30, 2017): 121–0. http://dx.doi.org/10.5604/01.3001.0010.1700.
Upholstery materials during their performance experience biaxial deformations, which are effected by friction in the contact zones: material-to-human skin, material-to-material, and material-to-inner parts of the furniture. The aim of this research was to define the effect of friction in the punch-to-specimen contact zone upon the tearing character and strength of non-perforated and perforated synthetic leathers under biaxial punching. Tests were performed with three different punches. The variation of friction coefficients in the punch-to-leather contact zone was achieved by the application of four different lubricants. Leather samples were investigated on the face (vinyl) and reverse (textile) sides. The results of the investigations confirmed that the maximal punching force Pmax increases with an increase in the punch size. The same tendency is valid in cases where different levels of friction act in the punch-to-specimen contact zone or whether the specimens were punched from both sides. Dependencies exist between area S of the punch-to-specimen contact zone during tearing and the average static μSA and dynamic μDA friction coefficients.
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Xia, Qin Xiang, Teng Xu, Hu Bo, Hong Chen Zhang, and Livan Fratini. "Influence of Oblique Edge Blanking on the Online Punching Quality after Stretch Bending." Defect and Diffusion Forum 385 (July 2018): 430–36. http://dx.doi.org/10.4028/www.scientific.net/ddf.385.430.
The oblique edge punching was proposed to reduce the surrounding sag failure occurred under the large punching force during online punching after stretch bending. The finite element models under three different kinds of punches were stablished and the punching processes were simulated by using the DEFORM-3D software. Comparison between the flat-edge punch and the oblique edge punches were realized, and the optimal height of the oblique edge of the unilateral bevelled punch and the single-peak bevelled punch were obtained. Three kinds of punches were designed based on the simulation results, and the experiments for manufacturing the upper strip of the automobile door frame by the online punching after stretch bending were carried out. The results show that the depth of the surrounding sag of punching can be reduced significantly and the appearance quality can be improved effectively by the oblique edge blanking. The effect to reduce the depth of surrounding sag failure by the unilateral bevelled punch is better than that by the single-peak bevelled punch, and the depth of surrounding sag failure on the side near the edge tip of the unilateral bevelled punch is smaller than that on the side away from the edge tip.
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Ning, Jian Hua, and Zheng Ping Hai. "A Study on the Method for Punching Small Holes with Cold Stamping Dies." Applied Mechanics and Materials 456 (October 2013): 358–62. http://dx.doi.org/10.4028/www.scientific.net/amm.456.358.
this paper first determines the deformation modes of punching small-hole punches by analyzing the forms of the stress applied to die working parts. It analyzes the disadvantages of existing methods for preventing the buckling problem in punching small holes such as protective jackets and proposes a method for preventing the buckling of punches by reducing the punching force so as to make it possible to punch smaller holes.
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de Azevedo, Arthur, Mauro Guerra, Leonardo Caldas, and Lucas Guimarães-Ferreira. "Acute Caffeine Ingestion did not Enhance Punch Performance in Professional Mixed-Martial Arts Athletes." Nutrients 11, no. 6 (June 25, 2019): 1422. http://dx.doi.org/10.3390/nu11061422.
Mixed martial arts (MMA) is a combat sport where competitors utilize strikes (punches, kicks, knees, and elbows) and submission techniques to defeat opponents in a cage or ring. The aim of this study was to investigate the effect of acute caffeine ingestion on punching performance by professional MMA athletes. The study used a double-blind, counterbalanced, crossover design. Eleven professional MMA competitors (27.6 ± 4.3 years and 83.5 ± 7.8 kg of body weight) ingested a dose of caffeine (5 mg·kg−1) or placebo 60 min prior to three sets of punching. Each set consisted of 15 s, at which participants were asked to perform straight punches with maximum strength and frequency with his dominant arm. After each set, a 45 s recovery time was applied. Using a force transducer attached to a cushioned plate, the punch frequency, and mean and maximal punch force was measured. The readiness to invest in both physical (RTIPE) and mental (RTIME) effort was assessed prior to the protocol, and the rating of perceived exertion (RPE) was recorded after. Caffeine ingestion did not result in increased punching frequency, mean and maximum punch force, RTIPE, RTIME, and RPE when compared to the placebo condition. Based on these results, acute caffeine ingestion did not improve punching performance in professional MMA athletes.
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Dinu, Daniel, Benjamin Millot, Jean Slawinski, and Julien Louis. "An Examination of the Biomechanics of the Cross, Hook and Uppercut between Two Elite Boxing Groups." Proceedings 49, no. 1 (June 15, 2020): 61. http://dx.doi.org/10.3390/proceedings2020049061.
In boxing, an efficient punch requires a combination of force, velocity and stability of the athlete. Being able to monitor these parameters has the potential to better inform training practices required to reach high performance. Hence, the aim of this study was to investigate the differences in punching execution between two groups of elite boxers (senior vs. junior) using three biomechanical indicators of performance in boxing. Each athlete was equipped with an instrumented suit composed of 17 inertial measurement units (IMU) and were asked to perform several series of punches with 3 standardized punching techniques (cross, hook and uppercut) on a punching bag with maximal force. Linear velocity, stability and punch forces were computed from the different sensors. Our findings show that senior boxers systematically produced more force and at a higher velocity for the three punching techniques compared to juniors. The IMU analysis also reveals differences of joint contributions between seniors and juniors, juniors presenting a higher contribution of the shoulder for the three punching techniques.
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Yao, Pan Pan, and Qiang Wang. "Investigation on Hole Punching Process with Combined Punch to Improve Surface Quality during the Materials Forming Process." Key Engineering Materials 737 (June 2017): 77–82. http://dx.doi.org/10.4028/www.scientific.net/kem.737.77.
The present work shows the viability of a combined punch that makes possible to perform a hole punching followed by a hole burnishing in only one operation. The advantage of this combined punch is forming processes in only one process on medium thickness plate. In this work were tested two different configurations of punches which one of them is the conventional punch and another is a new structure of combined punch. The new structure of combined punch is added the step and inclined edge at the cutting edge on the basis of conventional punch. They are made of the same materials that are Cr12MoV. The new structure of combined punch and the conventional punch are studied by using numerical simulation and experimental research in this paper. During the materials forming process of hole punching, the simulation software ANSYS is used to simulate. The YZ32-100 Hydraulic press with nominal and the self-made die sets and the thick of 16mm Q235 sheet metal is selected in this experiment. The analysis of the obtained results showed that the hole surface quality of combined punch is superior to the conventional punch. It is prove that the new structure of combined punch can improve quality of punching.
Håkansson, Maja. "Implementation of nut piercing from below in a stamping die : A case study at Volvo Car Body Components." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105033.
In today's car industries, low investment costs and high production rates are sought. By using nut piercing in the stamping dies in the manufacture of body components, otherwise necessary subsequent tempos can be reduced. The goal of the work was to implement nut piercing from below in a reference die to be able to use this type of operation in future projects. The main problem when implementing nut piercing from below is to be able to handle and evacuate the scrap piece that remains after the punching. By studying the equipment in the reference die, a deeper understanding of the process could be obtained, at the same time as information and necessary material were collected by expertise and the case company's suppliers for nut piercing. The recommendation to the case company provides a solution proposal for scrap evacuation as well as the components involved to be able to carry out the operation.
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Delacruz, Gian. "Punching bag trainer." Click here to view, 2009. http://digitalcommons.calpoly.edu/eesp/11/.
Thesis (B.S.)--California Polytechnic State University, 2009. Project advisor: David Braun. Title from PDF title page; viewed on Feb. 4, 2010. Includes bibliographical references. Also available on microfiche.
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Antunes, Filipe. "Estudo da perfuração de chapas grossas de aço ASTM A-36." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/173781.
O presente trabalho estuda a variação do diâmetro inicial e diâmetro final de um furo puncionado feito em uma chapa de aço ASTM A-36 com 12,7 mm de espessura. São propostas três geometrias diferentes de punção fabricados em aço AISI D2 e AISI S1 com diâmetro inicial 20 mm e final 22 mm. Os punções foram fabricados para realizarem o processo de puncionamento e brochamento com penetrações de avanço (asf) de 0,2 mm, 0,5 mm e 1 mm. O objetivo principal é reduzir a conicidade dos furos puncionados atualmente através do método convencional. As folgas entre punção e matriz (w) utilizadas foram de 3,1%, 7,8% e 15,7% da espessura da chapa de testes respectivamente. Para avaliação do desempenho de cada ferramenta, todos os furos puncionados foram medidos e tabelados. Entre os resultados encontrados, constatou-se que os punções com brochamento apresentam melhores valores que os convencionais em todos parâmetros analisados. As regiões de cisalhamento (Zc) e região de ruptura abrupta (Zr) também sofreram influência direta em função da geometria utilizada. The present work studies the variation of the initial diameter and final diameter of a punched hole made in an ASTM A-36 steel sheet with 12.7 mm of thickness. Three different punches geometries are proposed and manufactured from AISI D2 and AISI S1 steel with initial diameter 20 mm and final diameter 22 mm. The punches were manufactured to carry out the punching and broaching process with feed penetrations (asf) of 0.2 mm, 0.5 mm and 1 mm. The main objective is to reduce the conicity of the punched holes currently through the conventional method. The clearance between punch and die (w) used were 3.1%, 7.8% and 15.7% of the thickness of the test plate respectively. To evaluate the performance of each tool, all punched holes were measured and tabulated. Among the results, it was observed that the punches with a broaching showed better values than the conventional ones in all analyzed parameters. The regions of shear (Zc) and region of abrupt rupture (Zr) also had a direct influence in function of the geometry used.
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Lyčka, Lukáš. "Punching Shear of Flat Slabs." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-408019.
The use of flat slabs in constructions due to its many functional and economic advantages is wide-spread. Behavior of flat slabs in shear and flexure is a fairly complex problem. Therefore, the punching shear failure belongs to one of the most critical aspects in the design of concrete buildings. Over the last decades several buildings have collapsed due to the failure of the punching shear strength, resulting in loss of lives and financial damages. These disasters revealed gaps in the current (or former) design codes and recommendations. As a part of theoretical framework of the dissertation a method for predicting the punching shear strength of flat slabs was developed. Several experiments on scaled down slabs were conducted in order to verify the proposed method and for optimization of its parameters. Proposed method in development predicts the punching shear for slabs without shear reinforcement according to the EC2 and replaces the area of the shear crack with a system of struts and ties.
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Tazaly, Zeinab. "Punching Shear Capacity of Fibre Reinforced Concrete Slabs with Conventional Reinforcement : Computational analysis of punching models." Thesis, KTH, Bro- och stålbyggnad, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118825.
Steel fibre reinforced concrete is not a novel concept, it has been around since the mid-1900s, but despite its great success in shotcrete-reinforced rock walls and industrial floors it has not made any impact on either beams or elevated slab. Apparently, the absence of standards is the main reason. However, the combination of steel fibre reinforced concrete and conventional reinforcement has in many researches shown to emphasize good bearing capacrty. In this thesis, two punching shear capacity models have been analysed and adapted on 136 test slabs perfomred by previous researchers. The first punching model altemative is proposed in DAfStB - BetonKalender 201l, and the second punching model alternative is established in Swedish Concrete Association - Report No. 4 1994. Due to missing information of the experimental measured residual tensile strength, a theoretical residual tensile strength was estimated in two different manners to be able to adapt the DAfStB punching model altemative on the refereed test slabs. The first solution is an derivation of a suggestion made by Silfiverbrand (2000) and the second solution is drawn from a proposal made by Choi etal. (2007). The result indicates that the SCA punching model alternative is easier to adapt and provides the most representative result. Also DAfStb altemative with the second solution of estimating the residual strength contributes to arbitrary result, however due to the uncertainty of the estimation of the residual tensile strength, the SCA punching model is recommended to be applied until further investigation can confirm the accuracy of the DAfStB alternative with experimentally obtained residual tensile strength.
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Shehata, Ibrahim Abd El Malik. "Theory of punching in concrete slabs." Thesis, University of Westminster, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481746.
Sampaio, Soares Luis Fernando. "Influence of slab continuity on punching resistance." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/48011.
This research addresses the design of reinforced concrete flat slabs for punching shear. Flat slabs are two way spanning slabs without downstand beams that are directly supported by columns. The thickness of flat slabs is typically governed by considerations of either deflection control or punching shear for which there is still no widely accepted theoretical treatment. The research seeks to develop a better understanding of the effects of in-plane restraint and flexural continuity on the punching resistance of flat slabs. The overriding aim is to determine whether flexural continuity is sufficient to explain the satisfactory performance of existing flat slabs which appear punching shear deficient when assessed against test data from isolated punching shear specimens. The influence of slab continuity on punching resistance is assessed through analysis of test data, nonlinear finite element analysis (NLFEA) and fib MC2010 Level of Approximation (LoA) IV which is based on the Critical Shear Crack Theory (CSCT) of Muttoni. The CSCT relates shear resistance to the width of the so-called ‘critical shear crack’ which depends on slab rotation. MC2010 has four LoA of which I to III are intended for design. Punching resistance is normally determined from tests on isolated slab-column specimens which are intended to simulate behaviour within the elastic line of contraflexure for radial moments, although the benefits of continuity on punching shear strength is well known. MC2010 LoA IV, which uses nonlinear finite element analysis to determine the slab rotation, is used to investigate and develop a better understanding of the influence of continuity on the punching shear resistance of flat slabs at edge and internal columns. The FE model is calibrated against relevant test data from both isolated and continuous specimens. Parametric studies are presented which show the superseded UK design code BS8110 to require significantly less punching shear reinforcement than EC2 (2004) and MC2010 LoA II which give reasonable strength predictions for isolated internal column punching specimens. Despite this, slabs designed to BS8110 have performed satisfactorily for many years. MC2010 LoA IV is used to show that punching resistance at internal columns can be increased significantly by restraint from the surrounding slab. The increase in punching resistance due to continuity is shown to be sufficient to explain the satisfactory performance of flat slabs designed to BS8110 at internal columns. However, the strength increase is variable and, in the case of uniformly loaded slabs, already largely included in BS8110 and EC2. The research also considers the influence of slab continuity on punching resistance at edge columns. Parametric studies are developed to examine the influence of shear force eccentricity, flexural reinforcement distribution between support and span, and modelling assumptions on the punching resistance of flat slabs at edge columns. Relating the punching resistance at edge columns to the elastic unbalanced moment as done in MC2010 LoA II and III is shown to be overly conservative for continuous slabs. The ACI 318 and EC2 practice of making the design punching resistance independent of the unbalanced moment is reviewed and shown to be reasonable particularly for continuous slabs. MC2010 LoA IV is shown to be a powerful tool for assessment, however the predictions for the method are very sensitive to the modelling assumptions and boundary conditions.
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Barbosa, Catarina de Lemos Grilo Ferreira. "Modelling metal punching using ductile failure criteria." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14422.
Mestrado em Engenharia Mecânica During the process of mechanical conforming of metal sheet by punching process, several factors influence the accuracy and final geometry of the hole punched. The properties of material used and its behavior in the face of imposed deformations, as well as process parameters influence the final result. High Strength Low Alloy steels (HSLA) are particularly suitable for structural parts that do not require severe forming, such as industrial shelving systems or furniture. Knowledge of mechanical punching operation is of utmost importance to planners of product, process and tooling, so you can get quality products at an acceptable level of waste. The numerical simulation can contribute significantly to the prediction of behavior, still in the planning phase of the product. The goal of this paper is analyze the influence of gap between punch and die during punching. The metal plate material was used with a thickness of 8mm DIN EN 10268 H 360 LA with gaps between punch and die ranging from 2% to 10%. For this we developed a 2D axisymmetric model in ABAQUS/Explicit software, Version 6.7 and the result were compared with literature data and practical experiment. Test showed that the gap of 2% showed the best result.. Durante o processo de conformação metálica por embutidura vários fatores influenciam na geometria final do puncionado. As propriedades do material usado e o seu comportamento perante conformações impostas, assim como característica do processo comprometem o resultado final. Aços HSLA são particularmente apropriado para componentes estruturais que não requerem conformação profunda, tal como os usados na industria de mobiliário metálico. Conhecimento em operações de embutidura mecânica é de maior importância para gestores de produto, processo e ferramentas, para obtenção de produtos de elevada qualidade e desperdício mínimo. A simulação numérica contribui significativamente para a previsão do comportamento ainda na fase de planeamento. O objetivo deste trabalho é analisar a influência da distância entre o punção e a matriz. Considerou-se uma variação entre 2 a 10% nesta análise. Para cumprir estes objetivos criou-se um modelo axissimetrico 2D no ABAQUS/Explicit Software versão 6.7 e o resultado foi comparado com dados bibliográficos e ensaios laboratoriais. Testes demonstraram que a distância entre o punção e a matriz de 2% proporciona o melhor resultado.
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Shao, Xiao-yun. "Punching shear strength of reinforced concrete slab." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/10727.
This thesis presents the results of punching shear tests performed on a 2 x 2 bay continuous slab with/and without supplementary supports. On the basis of these tests, the code method of calculating the ultimate strength of interior, edge and corner column connections of flat slab were investigated. The thickness of the specimen was 140 mm and the spans length were 2743 mm. The ACI 318-89, BS 8110-85 and CEB-FIP 90 Codes were critically reviewed by comparing with the experiment results and results from the literature. It was found that in general the Code predictions are reasonable but for corner column connections the ACI Code over-estimates the ultimate shear capacity of the slab and BS 8110-85 requirements for edge and corner column connections are simplistic. The experimental results show that the supplementary supports can increase the ultimate punching shear capacity when the supports are properly located.
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Todd, Graham. "Born Under Punches." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1490874484128209.
Bhadury, Poushali. "Punching Up, Punching Down." In Dust Off the Gold Medal, 34–50. New York: Routledge, 2021. http://dx.doi.org/10.4324/9780367337223-2-3.
Weik, Martin H. "punching." In Computer Science and Communications Dictionary, 1378. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_15143.
Gooch, Jan W. "Punching." In Encyclopedic Dictionary of Polymers, 597. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_9613.
Weik, Martin H. "punching position." In Computer Science and Communications Dictionary, 1378. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_15144.
Weik, Martin H. "multiple punching." In Computer Science and Communications Dictionary, 1060. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_11963.
Sousa, Joao, Luis Figueiredo, Jose Machado, and Joao P. Mendonca. "Measuring the Punching Profile of a Punch And Bind Machine." In Lecture Notes in Mechanical Engineering, 727–32. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-68619-6_70.
Harder, Hans. "Prologue: Late Nineteenth and Twentieth Century Asian Punch Versions and Related Satirical Journals." In Asian Punches, 1–11. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-28607-0_1.
Ettmueller, Eliane Ursula. "Abū Nazzāra’s Journey from Victorious Egypt to Splendorous Paris: The Making of an Arabic Punch." In Asian Punches, 219–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-28607-0_10.
Elmas, Elif. "Teodor Kassab’s Adaption of the Ottoman Shadow Theatre Karagöz." In Asian Punches, 245–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-28607-0_11.
Figueiredo, Luis, Joao Sousa, Jose Machado, and Joao P. Mendonca. "Optimized punches geometry for paper punching systems: An industrial approach." In 2017 4th International Conference on Control, Decision and Information Technologies (CoDIT). IEEE, 2017. http://dx.doi.org/10.1109/codit.2017.8102704.
Yang, Guobiao, Tian Bai, Wan Xu, Junrui Li, Lianxiang Yang, Dajun Zhou, and Changqing Du. "Dimension Study of Punched Hole Using Conical Tipped Punches." In SAE 2016 World Congress and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2016. http://dx.doi.org/10.4271/2016-01-0364.
Sousa, João, Tiago Pinho, Luís Figueiredo, João Mendonça, and José Machado. "Development and Optimization of a Paper Punching System." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52371.
This paper focuses on the study and optimization of binding machine’s paper punching system, especially on the required actuating torque. The mechanical properties of paper, which are required to perform numerical simulation, are revised from current bibliography. Various hole types, required for the different binding systems are analyzed as well as the puncher’s geometry. The actuating mechanisms responsible for the punching movement from several binding machines are presented. Torque measurements were performed to demonstrate the potential improvements from a new puncher configuration and/or actuating mechanism.
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Nagarajan, Pratapkumar, Donggang Yao, Thomas S. Ellis, and Reza Azadegan. "Close-Die Embossing of Multichannel Waveguides." In ASME 2007 International Manufacturing Science and Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/msec2007-31059.
A combined punching and embossing process was developed for fabrication of 3-D multichannel waveguides. The close-die setup overcomes the lateral flow problem experienced by the standard hot embossing process, thereby allowing buildup of embossing pressure and replication of 3-D features. The embossing tool for this purpose includes a punching head and the to-be-replicated features in the socket behind the punching head. During the process, the embossing tool first punches out a billet from a large blank and then embosses this billet in the socket. The combined operation allows for accurate blanking and provides a close-die process for embossing pressure buildup. ABS and PMMA were chosen as two polymers for waveguide embossing. In both cases, cycle times around 7 minutes resulted. While ejection problems were experienced by PMMA, a relatively brittle polymer, 4-channel waveguides with crispy edges and accurate dimensions were successfully fabricated using ABS, the tougher polymer.
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Alva, Ujval, and Satyandra K. Gupta. "Automated Punch Shape Synthesis for Sheet Metal Bending Operations." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/dfm-8901.
Abstract Sheet metal bending is a process in which bends are formed using a combination of a punch and a die. A very large number of mechanical products such as furniture panels, shelves, cabinets, housing for electro-mechanical devices etc. are created by using the sheet metal bending process. Bending tools need to satisfy the following two criteria: (1) tools should be able to withstand bending forces, and (2) tool shapes should be such that there is no tool-part interference. In this paper, we describe a systematic methodology for automatically synthesizing shapes of bending punches. We create parametric geometric models of punches. These parametric models describe the family of possible punch shapes. Using the part geometry and parametric punch shape models, we automatically generate constraints on tool parameters that eliminate the possibility of part-tool interference. We use mixed integer programming techniques to identify parameters of punch shapes that result in the maximum punch strength. Finally, we perform strength analysis of the designed punch shape to verify that the designed punch shape is capable of withstanding the bending forces.
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Sabuwala, Tapan, Xiangyu Dai, and Gustavo Gioia. "Elastic Polyether Polyurethane Foams Under Punching: Experiments, Theory and Simulations." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40538.
We carry out punching experiments on low-density elastic polyether polyurethane (EPP) foams. The punch is rigid and wedge-shaped, and the specimens are either cubic or brick-shaped. The experimental results display some striking features, most notably a mechanical response that remains linear up to a penetration of the punch of about 40% of the height of the specimen. At higher penetrations, the mechanical response turns abruptly nonlinear: for the cubic specimens, there is a momentary loss of stiffness; for the brick-shaped specimens, there is a sizable increase in stiffness. We formulate a simple theoretical model of the punching of low-density EPP foams. In this model, a cell of the microstruture of an EPP foam behaves as a bistable elastic structure under compression, so that there are two preferred values of strain corresponding to two configurational phases of the foam. We use the model to explain the most salient experimental observations. We also formulate a micromechanical, mean-field model of EPP foams, implement the model in a general-purpose finite element code, and carry out computational simulations of the punching experiments. The computational results are in good accord with the experimental results, and they allow us to verify some of the assumptions on which the theoretical model is predicated.
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Vandenberg, Theodore W., Christopher R. Nehme, and Thomas P. James. "Application of Microforming to Create Chondrocyte Home Sites in a Natural Cartilage Matrix." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36953.
Articular cartilage degeneration is a central pathological feature of osteoarthritis. Cartilage in the adult does not regenerate in vivo and, as a result, cartilage damage in osteoarthritis is irreversible. With our ever-aging population, osteoarthritis has become a leading cause of disability and unfortunately, no optimal treatments for osteoarthritis are currently available. To address this problem, a research community is focused on the development of both natural and synthetic biodegradable tissue scaffolds. The scaffolds must contain depressions or holes for the purpose of chondrocyte seeding and growth in order to create an implantable construct. In addition to chondrocytes, cartilage tissue consists of the extracellular matrix (ECM). Studies of many tissue types have established that ECM plays an important role in regulating cell behavior and controlling processes such as tissue differentiation and tumor progression. Unlike most natural tissues, adult cartilage ECM is exceptionally dense and lacking in vascularity, which makes it difficult for chondrocytes to be transplanted directly into the matrix. Current methods of creating cell home sites through chemical decellularization of the ECM degrade the mechanical integrity of the cartilage tissue. The research conducted here used a mechanical, rather than chemical, method to create cell home sites. A novel micropunching machine was developed to fabricate 200 μm diameter holes in cartilage, thereby creating a porous natural scaffold while maintaining a healthy ECM. Equine articular cartilage slices were harvested from the cadaver’s back knee joint and cryo-sectioned into 100 μm thick slices. Using die clearances of 3.7%, 6.8%, and 8.9%, the results indicate that micro-scale holes can be mechanically punched in cartilage tissue. The maximum punching force showed a slight trend of decreasing as die clearance increased, but there was no statistical significance. Punching force, as well as hole size, was highly dependent on sample hydration. Upon inspection, the resulting hole sizes were approximately 50 μm to 150 um, indicating 25% to 75% shrinkage in reference to the male punch diameter. Finally, the resulting hole shape was observed to be slightly non-circular and the edges of the hole exhibited a raggedness, which was indicative of the cartilage tearing during hole punching.
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Zhang, Bin, M. Dodaran, S. Shao, and W. J. Meng. "Mechanical Response and Incomplete Filling in Compression Molding With Microscale Double-Punch Sets." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-11521.
Abstract Forming nano-/micro-scale surface patterns on metal surfaces by direct compression molding is an important means for achieving small scale surface features with potential usage in wide ranging technological applications. Geometric fidelity of molded features and the corresponding molding response are of critical importance in determining the usefulness of the molding replication technique. In this paper, two series of microscale punches made of tool steels were fabricated using Ga+ focused ion beam (FIB). In one series, the punch consists of a single protruding rectangular strip of different width, w (dubbed the “single punch”). In the other series, the punch consists of two rectangular strips of identical dimensions separated by a spacing in between, s (dubbed the “double punch”). These so-fabricated punches were used to mold elemental single crystal Al. The mechanical response during compression molding was measured and analyzed. For the double-punch experiments, measured characteristic molding pressure exhibited a significant dependence on the spacing to punch width ratio, λ = s/w, as well as a significant dependence on s when λ was fixed. The molded features were examined and the phenomenon of incomplete filling was observed to occur at λ < 0.5.
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Riznychuk, Roman. "Contact Area Variation in Elastic Indentation Problems." In ASME/STLE 2009 International Joint Tribology Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/ijtc2009-15009.
Contact problem of the frictionless indentation of elastic half-space by smooth rigid punch of curved profile is investigated. An exact expression of the contact pressure distribution for a curved profile punch in terms of integral involving the pressure distribution for sequence of flat punches is derived. The method is illustrated and validated by comparison with some well-known analytical solutions.
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Thomas, Arpit, and Anant Kumar Singh. "Magnetorheological Nano-Surface-Finishing of Tapered Cavity of Chrome Steel Punch." In ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2851.
Abstract The need for finishing chrome steel punch has drastically increased in order to obtain products with high quality and productivity. Chrome steel finds its application in manufacturing of punch and dies because of its higher hardness as varies up to 62 HRC. The paper is focused on improving the productivity of chrome steel punch through improving the surface finish using magnetorheological finishing process with a solid rotating tool core. The traditional method used for finishing of the chrome steel punch involves diamond lapping where machining marks and surface micro cracks are observed. In punching operation, the punch undergoes adhesive wear which can be controlled if the surface finish of the punch is improved. The surface finish obtained after diamond lapping process is up to 408 nm range. In present work, the further finishing of the tapered cavity of chrome steel punch is carried out. The chrome steel punch workpiece is rotated in a direction opposite to the rotation of the tapered tool tip surface in order to efficiently perform the finishing operation. The final surface roughness value of the flat surface of circular tapered punch is obtained as 26 nm from 420nm while the roughness value of the tapered surface is obtained as 22 nm from 408 nm in 90 minutes of finishing.
Звіти організацій з теми "Punchin":
1
Ilzetzki, Ethan, Carmen Reinhart, and Kenneth Rogoff. Why Is the Euro Punching Below Its Weight? Cambridge, MA: National Bureau of Economic Research, February 2020. http://dx.doi.org/10.3386/w26760.
Phan, Long T., and H. S. Lew. Punching shear resistance of lightweight concrete offshore structures for the Arctic:. Gaithersburg, MD: National Bureau of Standards, 1988. http://dx.doi.org/10.6028/nist.ir.88-4007.
McLean, David I., H. S. Lew, Long T. Phan, and Mary Sansalone. Punching shear resistance of lightweight concrete offshore structures for the Arctic :. Gaithersburg, MD: National Bureau of Standards, 1986. http://dx.doi.org/10.6028/nbs.ir.86-3388.
McLean, David I., H. S. Lew, Long T. Phan, and Hae In Kim. Punching shear resistance of lightweight concrete offshore structures for the Arctic :. Gaithersburg, MD: National Bureau of Standards, 1986. http://dx.doi.org/10.6028/nbs.ir.86-3454.
Phan, Long T., H. S. Lew, and David I. McLean. Punching shear resistance of lightweight concrete offshore structures for the Arctic :. Gaithersburg, MD: National Bureau of Standards, 1986. http://dx.doi.org/10.6028/nbs.ir.86-3440.
Pindyck, Eben. Punched in the Face: Collected Essays and Reportage. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.1877.
Saleh, Tarik A., Matthew Estevan Quintana, and Tobias J. Romero. Shear Punch Testing of BOR-60 Irradiated TEM Specimens. Office of Scientific and Technical Information (OSTI), June 2017. http://dx.doi.org/10.2172/1363742.
Saleh, Tarik A., Matthew Estevan Quintana, and Tobias J. Romero. Shear Punch Testing on ATR Irradiated MA956 FeCrAl Alloy. Office of Scientific and Technical Information (OSTI), June 2017. http://dx.doi.org/10.2172/1363743.
Lucon, Enrico, Jake Benzing, and Nik Hrabe. Development and validation of small punch testing at NIST. Gaithersburg, MD: National Institute of Standards and Technology, April 2020. http://dx.doi.org/10.6028/nist.ir.8303.
Preisig, J. R., and A. J. Stevens. Estimation of Neutron Punch-Through in Circular Shielding Penetrations. Office of Scientific and Technical Information (OSTI), November 1994. http://dx.doi.org/10.2172/1119206.
