Interfacial Stress Analysis and Fracture of a Bi-Material Strip With a Heterogeneous Underfill

2003 ◽  
Vol 125 (3) ◽  
pp. 400-413 ◽  
Author(s):  
Ji Eun Park ◽  
Iwona Jasiuk ◽  
Aleksander Zubelewicz
Keyword(s):  
Composite Material ◽  
Stress Intensity ◽  
Polymer Matrix ◽  
Flip Chip ◽  
Thermal Loading ◽  
Interfacial Stress ◽  
J Integral ◽  
Intensity Factors ◽  
Main Components ◽  
Random Particle

Flip chip assemblies used in electronic packaging consist of three main components (layers): chip, underfill, and substrate. In this paper, the flip chip assembly is represented as a bi-material strip consisting of the chip and underfill. Our analysis is focused on delamination along the chip-underfill interface due to thermal loading. The underfill is modeled as a composite material made of a polymer matrix and silica particles. Interfacial stresses are studied for several particle configurations: cases of one, two, or three particles near the interface and 30 different random particle arrangements. Interfacial fracture is investigated by evaluating the J integral and stress intensity factors. Statistics of random particle arrangements in the underfill are also discussed. The interfacial stress and fracture analyses give the same trends.

Reliability Evaluation of Flip Chip Using Stress Intensity Factors of an Interface Crack

2003 ◽  
Author(s):  
Won-Keun Kim ◽  
Toru Ikeda ◽  
Noriyuki Miyazaki
Keyword(s):  
Stress Intensity ◽  
Interface Crack ◽  
Stress Intensity Factors ◽  
Flip Chip ◽  
Liquid Crystal Display ◽  
Dissimilar Materials ◽  
Circuit Board ◽  
Electrical Performance ◽  
Intensity Factors ◽  
Adhesive Film

Anisotropic Conductive Adhesive Film (ACF) has been used for electronic assemblies such as the connection between a Liquid Crystal Display (LCD) panel and a flexible print circuit board (FPC). ACF is expected to be a key technology for flip chip packaging and chip size packaging. The goal of our work is to provide an optimum design scheme to achieve the best combination of electrical performance and mechanical reliability for electronic packages using the ACF. This study presents an evaluation technology for the delamination of the ACF connections. We utilized the stress intensity factors of an interface crack between jointed dissimilar materials. The evaluation technology presented herein was found to provide reliability of an electronic package using the ACF connection during the solder reflow process.

Formulation for Stress Intensity Factors and J-Integral Calculation by Eddy Current Testing

2015 ◽  
Vol 660 ◽  
pp. 225-230 ◽  
Author(s):  
Salaheddine Harzallah ◽  
Mohamed Chabaat ◽  
Sekoura Benissad
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Eddy Current ◽  
Eddy Currents ◽  
J Integral ◽  
Intensity Factors ◽  
Magnetic Vector ◽  
Current Testing ◽  
Set Up

In this paper, we present a method for computing the Stress Intensity Factor (SIF) and J-Integral, by measuring and testing related Eddy currents. In the process, we provide a magnetic vector based formulations for the theoretical set up. Furthermore, we provide relevant applications having theory consistent results.

scholarly journals Influence of Pressure and Thermal Parameters on Stresses Analysis of Pressurized and Cracked Pipes

2019 ◽  
Vol 35 (6) ◽  
pp. 1640-1646
Author(s):  
Abdullah K. Okab ◽  
Khalid A. Mohammed ◽  
Abdurahman A. Gatta
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
J Integral ◽  
Stress Distributions ◽  
Intensity Factors ◽  
Modeling Process ◽  
Oil Gas ◽  
Pressurized Cylinder

Due to the dangerous alarm for many engineering applications such as energy generating systems and pipelines transporting oil, gas and its derivatives under high-pressure, a study of the effect of thermal and mechanical loading on the cracked materials and pipes at high-temperature environments is required. In this work, the influence of the thermal loadings on stresses analysis of pressurized and cracked pressurized pipes has been solved numerically where the mode I crack's type has been considered. The modeling process mainly aims to find the stress intensity factor, J-integral calculations and the stress distributions. The accuracy of the results has been compared with analytical solutions of a pressurized cylinder. The mesh around the crack have been modeled in a careful way to obtain accurate stress distributions. It was found that the surface’s temperature has a significant effect on stress distributions, for example, the stresses increased by 50% with increasing the temperature differences between the inner and outer pipe’s diameter. Additionally, the stress intensity factor and the J-integrals values were calculated for different crack length ratios and temperature differences. It is found at the crack length ratio of 0.6 the stress intensity factors increased up to 50% from 45 to 76 and J-integral increased by 77% from 250 kN/m to 430 kN/m. Also, the influence of fluid’s temperature investigated, and the result showed that by increasing the fluid’s temperature without cracks, the stresses decreased by 33%. Also, it was found that for different crack length ratios the J-integral and stress intensity reduces when the fluid’s temperature increases.

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