A study on warpage behavior of EMC in post-mold cure stage using Moldex3D

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 000826-000850 ◽  
Author(s):  
Hsu Chih-Chung ◽  
Srikar Vallury ◽  
Srikar Vallury ◽  
Kai Lin ◽  
Anthony Yang
Keyword(s):  
Three Dimensional ◽  
Viscoelastic Behavior ◽  
Product Yield ◽  
Maxwell Model ◽  
Factors Affecting ◽  
Numerical Predictions ◽  
Linear Viscoelastic Material ◽  
Cure Time ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Warpage and residual stress are the two most important factors affecting product yield rate and reliability in IC encapsulation process. This study presents the prediction of warpage in post-mold cure stage using a three-dimensional finite element approach coupled with linear viscoelastic material property. Furthermore, cure-induced volumetric shrinkage and thermal expansion mismatch are considered. The shrinkage of the EMC is described by Pressure-Volume-Temperature-Cure (PVTC) model, and Generalized Maxwell model; WLF relation is adopted to describe the viscoelastic behavior of EMC. In order to obtain accurate numerical results, Cure-Time-Temperature superposition is considered. For verifying the numerical predictions of three dimensional simulations, the calculated results are compared with the available experimental data from literature.

Study on the critical loosening condition toward a new design guideline for bolted joints

2018 ◽  
Vol 233 (9) ◽  
pp. 3302-3316 ◽  
Author(s):  
Hao Gong ◽  
Jianhua Liu ◽  
Xiaoyu Ding
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Simulation Method ◽  
Bolted Joints ◽  
Design Guideline ◽  
Factors Affecting ◽  
Dimensional Finite Element ◽  
Frictional Coefficients ◽  
Three Dimensional Finite Element ◽  
Fit Tolerance

An understanding of conditions that trigger the loosening of bolted joints is essential to ensure joint reliability. In this study, a three-dimensional finite element model of a typical bolted joint is developed, and a new simulation method is proposed to quantitatively identify the critical transverse force for initiating loosening. This force is used to evaluate the anti-loosening capacity of bolted joints. Using the proposed simulation method, the effects of factors affecting critical loosening are systematically studied. It is found that the preload, frictional coefficients at the thread and the bearing surfaces, clamped length, and fit tolerance mainly affected loosening. When the preload and friction coefficients are increased, and the clamped length and fit tolerance are reduced, loosening is inhibited. Experiments are performed to demonstrate the reliability of the results. Finally, a suggestion is proposed to improve the design guideline VDI 2230 for bolted joints, which considers the requirement of avoiding loosening under vibrational loading.

A Study on Process-Induced Warpage of Curing Mold of Composite Structures

2009 ◽  
Vol 79-82 ◽  
pp. 1173-1176
Author(s):  
Guang Quan Yue ◽  
Bo Ming Zhang ◽  
Shan Yi Du ◽  
Fu Hong Dai ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Thermal Load ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Coupling Problem ◽  
Dimensional Precision ◽  
Numerical Predictions ◽  
Dimensional Finite Element ◽  
Thermosetting Composite ◽  
Three Dimensional Finite Element

Framed curing mold is subjected to an uneven thermal load, gravity force and the pressures from composite parts and auxiliary tools during autoclave processing of thermosetting composite structures. And those loads induce the warpage of framed-mold. The warpage of framed-mold during autoclave processing influences dimensional precision of composite parts. In the present work, a three-dimensional finite element model for prediction of the warpage of framed-mold during autoclave processing has been developed. This model solved the coupling problem between the deformation and the temperature distribution of framed-mold and allows analysis of all major identified deformation influencing factors. And numerical predictions compare quite well with experimental measurements. A parametric study was performed using FEM program to examine the effect of varying the thickness of framed-mold, the shape and the dimension of mold vents.

On the limitations of two- and three-dimensional linear hydroelasticity analyses applied to a fast patrol boat

2009 ◽  
Vol 223 (3) ◽  
pp. 457-478 ◽  
Author(s):  
F M Santos ◽  
P Temarel ◽  
C Guedes Soares
Keyword(s):  
Dynamic Behaviour ◽  
Transfer Functions ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Body Motion ◽  
Numerical Predictions ◽  
Dimensional Finite Element ◽  
Hydroelastic Analysis ◽  
Three Dimensional Finite Element ◽  
Wave Induced

The aim of this paper is to study the symmetric (i.e. heave and pitch motions and distortions associated with vertical bending) wave-induced dynamic behaviour of a fast patrol boat using a unified hydroelasticity analysis. This includes two- and three-dimensional structural idealizations using beam and three-dimensional finite element modelling. The fluid—flexible structure interaction is carried out using three-dimensional potential flow analysis, for both structural idealizations, based on a pulsating source singularity distribution on the mean wetted surface. The calculations are carried out in regular waves for two forward speeds (Froude numbers Fn = 0.5 and 0.63) and three heading angles, i.e. 180 (head), 135, and 90 degrees. Results from full-scale trials are also presented in order to compare rigid body motion transfer functions with numerical predictions. There are large differences between numerically predicted and measured motions, as is to be expected for this fast hull form. The paper reports that the evaluation of the dynamic behaviour of the fast patrol boat, with small length to beam ratio, by means of the unified hydroelastic analysis, shows some inherent limitations of the beamlike approach for this particular type of vessel.

NUMERICAL SIMULATION OF DYNAMIC FAILURE FOR ALUMINA CERAMIC

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5553-5558
Author(s):  
REN HUILAN ◽  
NING JIANGUO
Keyword(s):  
Fracture Behavior ◽  
Dominant Role ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Plate Impact ◽  
Numerical Predictions ◽  
Dimensional Finite Element ◽  
Damage Process ◽  
Three Dimensional Finite Element ◽  
Impact Experiments

The plate impact experiments have been conducted to investigate the dynamic behavior of alumina. Based on the experimental observations, the three-dimensional finite element models of flyer and alumina target are established by adopting ANSYS/LS-DYNA, several cases were performed to investigate the fracture behavior of alumina target under impact loading. By analyzing the fracture mechanism and damage process of the alumina target, it is concluded that the nucleation and growth of great number of radial and axial cracks and circumferential cracks play a dominant role in the fracture behavior of alumina target. The stress histories of alumina target are simulated. By the comparison of experimental results with the numerical predictions, a good correlation is obtained.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Tire Modeling by Finite Elements

1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Rolling Contact ◽  
Test Problems ◽  
State Behavior ◽  
Normal Contact ◽  
New Developments ◽  
Applied Torque ◽  
Dimensional Finite Element ◽  
Tire Modeling ◽  
Three Dimensional Finite Element

Abstract Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.

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