Thermal-Mechanical Analysis of an NCA Type of Chip-on-Glass Assemblies

2000 ◽  
Author(s):  
Hsien-Chie Cheng ◽  
Ming-Hsiao Lee ◽  
Kuo-Ning Chiang ◽  
Chung-Wen Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Contact Resistance ◽  
Contact Stress ◽  
Manufacturing Process ◽  
Element Model ◽  
Conductive Adhesive ◽  
Physical Contact ◽  
Design Parameters ◽  
Design Quality

Abstract Since the electrical conduction in the COG assembly using a non-conductive adhesive takes place through the connection of the bump and the electrodes, the contact resistance can be applied to the evaluation of the design quality as well as the overall reliability of the particular assembly. It should be further noted that as reported in the literature (e.g., see Liu, 1996; Kristiansen et al, 1998; Nicewarner, 1999; Timsit, 1999), the contact resistance between the bump and the electrode on the substrate strongly depends on the contact stress and the contact area. A higher reliability of the packaging somewhat relies on better contact stability as well as larger bonding stresses. In order to explore the physical contact behaviors of a non-conductive adhesive type of COG assemblies, the contact pressure during manufacturing process sequences and during the temperature variation are extensively investigated using a three-dimensional nonlinear finite element model. The so-called death-birth simulation technique is applied to model the manufacturing process sequences. The typical COG assemblies associated with two types of micro-bumps that are made of different materials: metal and composite are considered as the test vehicle. The contact stress between the electrode and the bump is extensively compared at each manufacturing sequence as well as at elevated temperature in order to investigate the corresponding mechanical interaction. Furthermore, the adhesion stresses of the adhesive are also evaluated to further investigate the possibilities of cracking or delamination within the adhesive and in its interfaces with the die and with the substrate. At last, a parametric finite element model is performed over number of geometry/material design parameters to investigate their impact on the contact/adhesion stresses so as to attain a better reliability design.

scholarly journals Design optimization of vehicle asynchronous motors based on fractional harmonic response analysis

2021 ◽  
Vol 12 (1) ◽  
pp. 689-700
Author(s):  
Ao Lei ◽  
Chuan-Xue Song ◽  
Yu-Long Lei ◽  
Yao Fu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequency ◽  
Asynchronous Motor ◽  
Element Model ◽  
Design Parameters ◽  
Response Analysis ◽  
Harmonic Response ◽  
First Order ◽  
Harmonic Response Analysis

Abstract. To make vehicles more reliable and efficient, many researchers have tried to improve the rotor performance. Although certain achievements have been made, the previous finite element model did not reflect the historical process of the motor rotor well, and the rigidity and mass in rotor optimization are less discussed together. This paper firstly introduces fractional order into a finite element model to conduct the harmonic response analysis. Then, we propose an optimal design framework of a rotor. In the framework, objective functions of rigidity and mass are defined, and the relationship between high rigidity and the first-order frequency is discussed. In order to find the optimal values, an accelerated optimization method based on response surface (ARSO) is proposed to find the suitable design parameters of rigidity and mass. Because the higher rigidity can be transformed into the first-order natural frequency by objective function, this paper analyzes the first-order frequency and mass of a motor rotor in the experiment. The results proved that not only is the fractional model effective, but also the ARSO can optimize the rotor structure. The first-order natural frequency of asynchronous motor rotor is increased by 11.2 %, and the mass is reduced by 13.8 %, which can realize high stiffness and light mass of asynchronous motor rotors.

A 3D Finite Element Model of a Knee for Joint Contact Stress Analysis during Sport Activities

2004 ◽  
Vol 261-263 ◽  
pp. 513-518 ◽  
Author(s):  
Constantin Bratianu ◽  
Paul Rinderu ◽  
Lucian Gruionu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Contact Stress ◽  
Element Model ◽  
Orthotropic Materials ◽  
3D Finite Element ◽  
Human Knee ◽  
Contact Areas ◽  
3D Finite Element Model ◽  
Sports Activities

A 3D finite element model of a human knee was constructed to study the response of articular tissues to loads applied to the surface of the femur similar to normal and extreme movements of the joint as in sports activities. A solid model of the femoral and tibial cartilages and menisci were built from post mortem MR images of human knee at full extension using the Pro/Engineer software package. The knee kinematics data was registered for this model and successive articular surface positions were obtained as a function of flexion angle. The cartilage and menisci were modeled as nonlinear orthotropic materials and contact elements were used to compose the contact layer between articular surfaces. The model determined average contact areas and stress values, which were then compared with published experimental results for equivalent boundary conditions. The presence of menisci increased the contact area in the knee joint, thus creating lower contact stresses on the cartilage than those measured experimentally. Validation of results allows the utilization of 3D knee model for determining the contact areas and the contact stress field for diverse bones positions simulating sports activities.

scholarly journals Numerical analysis of concrete-filled spiral welded stainless steel tubes subjected to compression

2018 ◽  
Author(s):  
Dongxu Li ◽  
Brian Uy ◽  
Farhad Aslani ◽  
Chao Hou
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Element Model ◽  
Experimental Program ◽  
Design Parameters ◽  
Steel Tubes ◽  
Finite Element Software

Spiral welded stainless tubes are produced by helical welding of a continuous strip of stainless steel. Recently, concrete-filled spiral welded stainless steel tubes have found increasing application in the construction industry due to their ease of fabrication and aesthetic appeal. However, an in-depth understanding of the behaviour of this type of structure is still needed due to the lack of proper design guidance and insufficient experimental verification. In this paper, the mechanical performance of concrete-filled spiral welded stainless steel tubes will be numerically investigated with a commercial finite element software package, through which an experimental program can be designed properly. Specifically, the proposed finite element models take into account the effects of material and geometric nonlinearities. Moreover, the initial imperfections of stainless steel tubes and the form of helical welding will be appropriately included. Enhancement of the understanding of the analysis results can be achieved by extending results through a series of parametric studies based on the developed finite element model. Thus, the effects of various design parameters will be further evaluated by using the developed finite element model. Furthermore, for the purposes of wide application of such types of structure, the accuracy of the behaviour prediction in terms of ultimate strength based on current design codes will be studied. The authors herein compared the load capacity between the finite element analysis results and the existing codes of practice.

scholarly journals A study for the prediction of corona power on electrostatic precipitator based on simple and easy two-dimensional electrostatic simulation

2020 ◽  
Vol 9 (2) ◽  
pp. 586
Author(s):  
Chang-Hee Cho ◽  
Dong-Hoon Kim ◽  
Sang-Eon Park
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Response Surface ◽  
Electrostatic Precipitator ◽  
Three Dimensional ◽  
Element Model ◽  
Design Parameters ◽  
Two Dimensional ◽  
Stored Energy ◽  
Dimensional Finite Element

This study examines how the designing of an electrostatic precipitator can be carried out in a simple way. While it is of value to find out the theoretical values of design parameters using three-dimensional finite element model and numerical method, this study shows that employ-ing a two-dimensional finite element model and easily usable public-domain program is equally simple and fast. Variations of some physical properties occurring between an electrode and a duct are expressed using two design parameters. In this process, the design of the experi-ment and the response surface method are used based on the two-dimensional finite element model, as well as electrostatic simulation. A test using an electrostatic precipitator is performed and it is confirmed that a variation of corona power by the test is most similar with the varia-tion of stored energy by the simulation. A conversion factor that can predict corona power with the response surface function for the stored energy is proposed.  

The Study of Spacecraft Finite Element Model Updating System

2011 ◽  
Vol 121-126 ◽  
pp. 4852-4857
Author(s):  
Xun Tao Liu ◽  
Zhao Bo Chen ◽  
Shan Yun Huang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Frequency Error ◽  
Analysis Tool ◽  
Design Quality ◽  
Vibration Direction ◽  
Finite Element Technology

with the development of finite element technology, finite element model is becoming to the main analysis tool. However, because some theoretic assumptions, unsuitable constraint and uncertain material property are applied, the simulation result of finite element model isn’t different from the testing data. In order to improve the design quality and safety of spacecraft, this paper deduced the formula of spacecraft finite element updating, developed the spacecraft finite element model updating system, the software mainly of five parts: the frequency response function calculation, the loading inverse solution, the finite element model updating, the data display, virtual experimentation. Software can complete exciting force inverse, parameter sensitivity analysis, parameters screening and finite element model updating. The calculation result of updated finite element model is in accordance with testing curve shape on the main vibration direction, first-order frequency error is ±5%, response error is ±10%. Software meet the need of finite element model updating, it provide a software base for spacecraft design.

scholarly journals Shape Influence of Active Material Micro-Structure on Diffusion and Contact Stress in Lithium-Ion Batteries

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 134
Author(s):  
Davide Clerici ◽  
Francesco Mocera ◽  
Aurelio Somà
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Contact Stress ◽  
Particle Shape ◽  
Active Material ◽  
Lithium Ion ◽  
Element Model ◽  
Contact Areas ◽  
Diffusion Stress ◽  
Contact Domain

Electrochemical-mechanical modelling is a key issue to estimate the damage of active material, as direct measurements cannot be performed due to the particles nanoscale. The aim of this paper is to overcome the common assumptions of spherical and standalone particle, proposing a general approach that considers a parametrized particle shape and studying its influence on the mechanical stresses which arise in active material particles during battery operation. The shape considered is a set of ellipsoids with variable aspect ratio (elongation), which aims to approximate real active material particles. Active material particle is divided in two domains: non-contact domain and contact domain, whether contact with neighbouring particles affects stress distribution or not. Non-contact areas are affected by diffusion stress, caused by lithium concentration gradient inside particles. Contact areas are affected simultaneously by diffusion stress and contact stress, caused by contact with neighbouring particles as a result of particle expansion due to lithium insertion. A finite element model is developed in Ansys™APDL to perform the multi-physics computation in non-spherical domain. The finite element model is validated in the spherical case by analytical models of diffusion and contact available for simple geometry. Then, the shape factor is derived to describe how particle shape affects mechanical stress in non-contact and contact domains.

Stresses in Polyethylene Liners in a Semiconstrained Ankle Prosthesis

2004 ◽  
Vol 126 (5) ◽  
pp. 636-640 ◽  
Author(s):  
M. C. Miller ◽  
P. Smolinski ◽  
S. Conti ◽  
K. Galik
Keyword(s):  
Finite Element ◽  
Body Weight ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Contact Stress ◽  
Element Model ◽  
Acetabular Cup ◽  
Ankle Prosthesis ◽  
Von Mises ◽  
Von Mises Stresses

A finite element model of a semiconstrained ankle implant with the tibia and fibula was constructed so that the stresses in the polyethylene liner could be computed. Two different widths of talar components were studied and proximal boundary conditions were computed from an inverse process providing a load of five times body weight appropriately distributed across the osseous structures. von Mises stresses indicated small regions of localized yielding and contact stresses that were similar to those in acetabular cup liners. A wider talar component with 36% more surface area reduced contact stress and von Mises stresses at the center of the polyethylene component by 17%.

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