The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
David Tarng - One of the best experts on this subject based on the ideXlab platform.
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evaluation of three point bending strength of thin silicon die with a consideration of geometric nonlinearity
IEEE Transactions on Device and Materials Reliability, 2019Co-Authors: M Y Tsai, P S Huang, J H Yeh, Huanyin Liu, Y C Chao, Fila Tsai, Daolong Chen, Mengkai Shih, David TarngAbstract:With the trends of electronic packaging development toward small size, low-profile features, high-pin count, and high performance, the 3D IC (Three-dimensional Integrated Circuits) or stacked-die packages have been gaining popularity. For such package applications, IC silicon wafers have to be ground and processed to be relatively thin and then the thin silicon dies cut from these wafers have to gain sufficient strength in order to bear high stresses resulting from process handling, reliability testing, and operations. Hence, the strength of the thin dies has to be determined to ensure the good reliability of the packages. Three-point bending test is commonly used for measuring die strength; however, the feasibility of the test is still questionable for determining the strength of relatively thin dies. Therefore, the feasibility of the linear beam theory is evaluated by a nonlinear finite element method (NFEM) with taking into account geometric nonlinearity in this study. The results show that this nonlinearity would cause errors of the strength of thin dies if calculated by the linear beam theory. The fitting equations of the correction factors ( $\eta $ ) to linear solutions, extracted from the NFEM simulation, are proposed and proved to be workable with very good accuracy. It is also found that the correction factor highly depends on the deflection ( $\delta $ ), span length (L) and radius of Roller Support (r), but not elastic modulus (E) and thickness (t) of test specimens. After the nonlinearity has to be taken into account for the relatively thin silicon dies, the consistent statistical strength data have been obtained for various thicknesses of the test die specimens.
Selda Oterkus - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Functionally Graded Timoshenko Beams by Using Peridynamics
Journal of Peridynamics and Nonlocal Modeling, 2020Co-Authors: Zhenghao Yang, Erkan Oterkus, Selda OterkusAbstract:In this study, a new peridynamic formulation is presented for functionally graded Timoshenko beams. The governing equations of the peridynamic formulation are obtained by utilising Euler-Lagrange equation and Taylor’s expansion. The proposed formulation is validated by considering a Timoshenko beam subjected to different boundary conditions including pinned Support-Roller Support, clamped-Roller Support and clamped-free boundary conditions. Results from peridynamics are compared against finite element analysis results. A very good agreement is obtained for transverse displacements, rotations and axial displacements along the beam.
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A state-based peridynamic formulation for functionally graded Euler-Bernoulli beams
Computer Modeling in Engineering & Sciences, 2020Co-Authors: Zhenghao Yang, Erkan Oterkus, Selda OterkusAbstract:In this study, a new state-based peridynamic formulation is developed for functionally graded Euler-Bernoulli beams. The equation of motion is developed by using Lagrange’s equation and Taylor series. Both axial and transverse displacements are taken into account as degrees of freedom. Four different boundary conditions are considered including pinned Support-Roller Support, pinned Support-pinned Support, clamped-clamped and clamped-free. Peridynamic results are compared against finite element analysis results for transverse and axial deformations and a very good agreement is observed for all different types of boundary conditions.
M Y Tsai - One of the best experts on this subject based on the ideXlab platform.
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evaluation of three point bending strength of thin silicon die with a consideration of geometric nonlinearity
IEEE Transactions on Device and Materials Reliability, 2019Co-Authors: M Y Tsai, P S Huang, J H Yeh, Huanyin Liu, Y C Chao, Fila Tsai, Daolong Chen, Mengkai Shih, David TarngAbstract:With the trends of electronic packaging development toward small size, low-profile features, high-pin count, and high performance, the 3D IC (Three-dimensional Integrated Circuits) or stacked-die packages have been gaining popularity. For such package applications, IC silicon wafers have to be ground and processed to be relatively thin and then the thin silicon dies cut from these wafers have to gain sufficient strength in order to bear high stresses resulting from process handling, reliability testing, and operations. Hence, the strength of the thin dies has to be determined to ensure the good reliability of the packages. Three-point bending test is commonly used for measuring die strength; however, the feasibility of the test is still questionable for determining the strength of relatively thin dies. Therefore, the feasibility of the linear beam theory is evaluated by a nonlinear finite element method (NFEM) with taking into account geometric nonlinearity in this study. The results show that this nonlinearity would cause errors of the strength of thin dies if calculated by the linear beam theory. The fitting equations of the correction factors ( $\eta $ ) to linear solutions, extracted from the NFEM simulation, are proposed and proved to be workable with very good accuracy. It is also found that the correction factor highly depends on the deflection ( $\delta $ ), span length (L) and radius of Roller Support (r), but not elastic modulus (E) and thickness (t) of test specimens. After the nonlinearity has to be taken into account for the relatively thin silicon dies, the consistent statistical strength data have been obtained for various thicknesses of the test die specimens.
Diehl, Gabriel Luis - One of the best experts on this subject based on the ideXlab platform.
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Desenvolvimento de uma ferramenta para dimensionamento de um sistema para movimentação de carga por roletes acionados
2019Co-Authors: Diehl, Gabriel LuisAbstract:A crescente expansão da automação industrial no cenário nacional, principalmente com a Indústria 4.0 e a robótica, impacta o crescimento da tecnologia aplicada aos sistemas de transporte interno de materiais, muitas vezes ignorados durante as atividades de rotina das indústrias. As esteiras de roletes proporcionam excelência no transporte de uma gama extremamente variada de produtos, desde caixas leves até paletes de peças robustas, devido a sua fácil construção e à grande disponibilidade de componentes no mercado. O projeto de esteiras de rolete inicia na coleta de informações acerca de sua aplicação, abrange a seleção de roletes e de sistemas de acionamento e transmissão, os cálculos de resistência estrutural e as análises dinâmicas, uma vez que determinado produto deve ser entregue com exatidão temporal em outro ponto do processo. O presente trabalho busca, portanto, entender o funcionamento de uma esteira de roletes para facilitar o trabalho do projetista mecânico no que diz respeito a sua construção, e criar uma planilha de cálculo que contenha a estrutura necessária para o correto desenvolvimento do projeto destes equipamentos, que podem ser utilizados em plantas industriais, em setores de logística e em células robotizadas. Após a obtenção dos dados de entrada e tomando como base as equações específicas de cada sistema, a planilha: 1) executa os cálculos de validação estrutural da base de sustentação e do suporte dos roletes; 2) apresenta os dados de potência, rotação e fator de serviço para acionar a esteira; 3) seleciona automaticamente, com base em equações, aplicação de Filtros Avançados e Macros, o rolete adequado para a esteira; 4) valida o sistema de transmissão apresentado para a esteira, com base nas potências de transmissão admissíveis conforme a ANSI; possibilitando o projeto executivo assertivo desse sistema de transporte.The growth of industrial automation in national scenery, mainly with Industry 4.0 and robotics, prompt the increase in technology applied on conveyor systems, often ignored during daily activities in industries. Roller conveyors provide excellence on transporting a great variety of products, since weightless packages to robust pallets due to its easy building process and to the big amount of assembly components for Rollers conveyors. Conveyor design begins on collecting information about the application, and encompasses the selection of Rollers, powering system, structural calculations and dynamic aspects, considering that product must be delivered at the right place in the right time throughout the process. This paper seeks, therefore, to understand the working subjects in a Roller conveyor in order to facilitate the design of this equipment by mechanical designers, and also to create a spreadsheet containing the structure calculations to develop the project of these equipment used in industrial plants, logistical services and robotic cells. After collecting the input data, and considering the equations for all the conveyor components, the electronic spreadsheet: 1) execute the calculations to validate the conveyor base and the Roller Support; 2) presents the power, rotation speed and service factor to select the power engine to the conveyor; 3) select, automatically, based in some equations and applying some Excel functions, the correct Roller for the system; 4) validates the transmission system, based in ANSI references for Roller chain transmission; clearly informing the essential data to the mechanical designer
Mark P. Silverman - One of the best experts on this subject based on the ideXlab platform.
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Reaction Forces on a Fixed Ladder in Static Equilibrium: Analysis and Definitive Experimental Test of the Ladder Problem
World Journal of Mechanics, 2018Co-Authors: Mark P. SilvermanAbstract:The development of a theoretical model to predict the four equilibrium forces of reaction on a simple ladder of non-adjustable length leaning against a wall has long remained an unresolved matter. The difficulty is that the problem is statically indeterminate and therefore requires complementary information to obtain a unique solution. This paper reports 1) a comprehensive theoretical analysis of the three fundamental models based on treating the ladder as a single Euler-Bernoulli beam, and 2) a detailed experimental investigation of the forces of reaction as a function of applied load and location of load. In contrast to previous untested proposals that the solution to the ladder problem lay in the axial constraint on compression or the transverse constraint on flexure, the experimental outcome of the present work showed unambiguously that 1) the ladder could be modeled the best by a pinned Support at the base (on the ground) and a Roller Support at the top (at the wall), and 2) the only complementary relation needed to resolve the static indeterminacy is the force of friction at the wall. Measurements were also made on the impact loading of a ladder by rapid ascent and descent of a climber. The results obtained were consistent with a simple dynamical model of the ladder as a linear elastic medium subject to a pulse perturbation. The solution to the ladder problem herein presented provides a basis for theoretical extension to other types of ladders. Of particular importance, given that accidents involving ladders in the workplace comprise a significant fraction of all industrial accidents, the theoretical relations reported here can help determine whether a collapsed structure, against which a ladder was applied, met regulatory safety limits or not.
