Development of a Program for Predicting Residual Stress Distribution in Multi-Stacked Film

2001 ◽  
Author(s):  
Hyeon Chang Choi ◽  
Jun Hyub Park ◽  
Yong Soo Park
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Prediction Method ◽  
Residual Stress Distribution ◽  
Residual Stress Field ◽  
Finite Element Program ◽  
Polysilicon Film ◽  
Element Method

Abstract The mean stresses of the single and multi-stacked film are experimentally investigated. After stacking several layers on a wafer, we measure the curvature on the wafer. Followed by peeling each layer stacked, we measure the curvature on the wafer, again. Mean residual stresses are calculated from radiuses of the curvatures using the Stoney’s equation[1]. Microcantilever beams is constructed by removing substrate and the deflection at the end of a beam is measured. Finite element method for determining residual stress distribution in multi-stacked films with a multi-step doping process is studied for use in micromachining applications. We propose a finite element program for residual stress analysis (RESA) in multi-stacked polysilicon film. The distribution of residual stress field in multi-stacked films is predicted using RESA. And it is established for the prediction method determining the deflection in a cantilever beam using finite element method (FEM).

Prediction of Tablet Characteristics from Residual Stress Distribution Estimated by the Finite Element Method

2013 ◽  
Vol 102 (10) ◽  
pp. 3678-3686 ◽  
Author(s):  
Yoshihiro Hayashi ◽  
Takahiro Miura ◽  
Takuya Shimada ◽  
Yoshinori Onuki ◽  
Yasuko Obata ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
The Finite Element Method ◽  
Element Method

scholarly journals Particulate Scale Multiparticle Finite Element Method Modeling on the 2D Compaction and Release of Copper Powder

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Liwen Zhou ◽  
Peng Han ◽  
Kun Liu ◽  
Lianghua Feng ◽  
Guangqiang Liu
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Force Transmission ◽  
Particle Deformation ◽  
Large Void ◽  
Pressure Release ◽  
Release Processes ◽  
Element Method

Herein, two-dimensional (2D) single-action die compaction process of copper (Cu) powder was simulated by the multiparticle finite element method (MPFEM) at particulate scale. The initial packing structure, generated by the discrete element method (DEM), was used as an input for the FEM model, where the mesh division of each particle was discretized. The evolution of macro- and microscopic properties, such as relative density, stress distribution, particle deformation, void filling behavior, and force transmission, during compaction and pressure release processes have been systematically studied. The results revealed that the force is mainly concentrated on largely deformed regions of the particles during compaction and formed a contact force network, which hindered the densification process. In the compact, the shorter side of the large void edges rendered higher stress than the longer side. On the other hand, the stress distribution of small void edges remained uniform. After pressure release, large residual stress was observed at the contact area of the adjacent particles and the maximum stress was observed at the particles’ edges. Moreover, the residual stress did not proceed to the interior of the particles. Meanwhile, the stress of large void edges has been completely released but exhibited a nonuniform distribution. The smaller fraction of void filling resulted in a larger reduction of the released stress after pressure removal. Also, the particles closer to the upper die exhibited higher average equivalent von Mises stress inside the particles during compaction and pressure release processes.

scholarly journals The Effects of Shot Distance and Impact Sequence on the Residual Stress Field in Shot Peening Finite Element Model

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 462
Author(s):  
Zhou Wang ◽  
Ming Shi ◽  
Jin Gan ◽  
Xiaoli Wang ◽  
Ying Yang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Shot Peening ◽  
Dynamic Models ◽  
Fe Simulation ◽  
Residual Stress Distribution ◽  
Fe Model ◽  
Residual Stress Field ◽  
The Impact

In order to investigate the effect of shot distance and impact sequence on the residual stress distribution of 42CrMo steel in shot peening (SP) finite element (FE) simulation, 3D dynamic models with order dimple pattern and stochastic dimple pattern were established via ABAQUS/Explicit 6.14, and the simulation results were compared with experiments. The results show that shot overlap has a significant effect on the residual stress distribution of peened parts. Meanwhile, there is a threshold (related to SP parameter) for shot distance in the vertical and horizontal directions. When the shot distance is greater than the threshold in this direction, the residual stress distribution after SP tends to be stable. The impact sequence has almost no effect on the impact of a small number of shots, but this effect will appear when the number of shots increases. It is necessary to avoid shot overlap and continuous impact of adjacent dimples when the FE model is established; on this basis, the distance between shots and the number of layers of the shots can be reduced as much as possible without affecting the residual stress distribution. In addition, the comparison of simulation and experimental results shows that the residual stress evaluation area consistent with the experimental measurement is essential to obtain accurate residual stress distribution in the FE simulation process.

Investigation of Residual Stresses Caused by Welding, Cladding and Tempering of Reactor Pressure Vessels

2003 ◽  
Author(s):  
V. I. Kostylev ◽  
B. Z. Margolin ◽  
A. Y. Varovin ◽  
E. Keim
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Weld Metal ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Reactor Pressure

Calculations of residual stress fields, which arise after welding, cladding and tempering, were performed as applied to reactor pressure vessels (RPVs) of WWER types. These calculations are based on a procedure, which takes into account Feα↔Feγ transformation happening in base and weld metal under welding and cladding, and also creep during tempering. The procedure is based on solutions of the temperature and non-isothermal elasto-plastic problem with and without creep by the finite element method. On the basis of the performed investigation it is shown that Feα↔Feγ transformation may affect the residual stress distribution. An analysis of cases has been performed for which the above effect is strong and for which this effect may be ignored. On the basis of the calculation performed, an engineering procedure is proposed that allows to determine the residual stress fields in welds of the WWER-440 and WWER-1000 for various durations of post-weld tempering.

Analysis of the Impact of a Shot at Low Velocity Using the Finite Element Method. Application to the Ultrasonic Shot-Peening Process

2006 ◽  
Vol 524-525 ◽  
pp. 337-342 ◽  
Author(s):  
Florent Cochennec ◽  
Emmanuelle Rouhaud ◽  
Delphine Retraint ◽  
Sébastien Rouquette ◽  
Arjen Roos
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Shot Peening ◽  
The Finite Element Method ◽  
Residual Stress Field ◽  
Low Velocity ◽  
Ultrasonic Shot Peening ◽  
Element Method

Shot-peening is a surface treatment widely used in the industry to improve fatigue life of mechanical components by introducing compressive residual stresses. Ultrasonic shot-peening is a recent development of this process. While the classical shot-peening process uses pneumatic energy to project the shots, ultrasonic peening uses high-power ultrasounds. This energy source allows the use of larger shots projected at lower velocity as compared to classical shot-peening. This work aims at studying the mechanical response (restitution coefficient, residual stress field) of a surface impacted by a shot at low velocity using the finite element method and experimental analysis. This paper presents the simulation of a single elastic steel shot normally impacting an Aluminum alloy plate considered to exhibit a linear-elastic behavior and non-linear isotropic work hardening characteristics. The numerical simulations are carried out for different impact velocities in order to take into account the heterogeneous shot velocity field observed in an ultrasonic shot-peening chamber. We compare the simulated rebound energy and the indentation profiles obtained for different impact velocities to experimental results. The simulated residual stress field topology shows a strong dependence on the shot velocity. While numerical results obtained at high impact energy agree well with literature results, the residual stress distribution simulated for low impact energies shows a tensile layer below the impacted area. The restitution coefficients and the indentation profiles compare well with the experiments.

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