Potential Failure Sites in a Flip-Chip Package With and Without Underfill

1998 ◽  
Vol 120 (4) ◽  
pp. 336-341 ◽  
Author(s):  
E. Madenci ◽  
S. Shkarayev ◽  
R. Mahajan
Keyword(s):  
Finite Element ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Flip Chip ◽  
Singular Behavior ◽  
Stress Concentrations ◽  
Finite Element Approach ◽  
Element Approach ◽  
Potential Failure ◽  
Material Discontinuities

In this study, the effect of underfill on the level of stress concentrations is investigated and possible failure sites are identified by using a global/local finite element approach. The global elements capture the exact singular behavior of the stresses near the geometric and material discontinuities. Application of the strain energy density criterion indicates the possible failure sites and how they shift due to the presence of underfill.

Modeling and Simulation of Transverse Cracks for Rotor-Bearing Systems

1996 ◽  
Author(s):  
Tachung Yang ◽  
Shi-An Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Strain Energy ◽  
Catastrophic Failure ◽  
Transverse Cracks ◽  
Finite Element Approach ◽  
Rotor Bearing ◽  
Element Approach ◽  
Rotating Shafts ◽  
Bearing System

Undetected cracking of rotating shafts can lead to catastrophic failure of turbomachinery. This paper investigated the dynamic response of rotor-bearing systems containing transverse cracks with a finite element approach. The breathing effect of cracks was analyzed based on the whirling conditions of the rotor, and different crack models were posed for different rotating speeds. The strain energy released due to the cracks was calculated. Then, the finite element for the shaft portion containing cracks was formulated and incorporated into the system matrices of the rotor-bearing system.

A Finite Element Approach by Contact Transformation for the Prediction of Structural Wear

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
James Shih-Shyn Wu ◽  
Yi-Tsung Lin ◽  
Yuan-Lung Lai ◽  
P.-Y. Ben Jar
Keyword(s):  
Finite Element ◽  
Strain Energy ◽  
Fe Simulation ◽  
Current Method ◽  
Solution Procedure ◽  
Computational Time ◽  
Contact Transformation ◽  
Qualitative Comparison ◽  
Finite Element Approach ◽  
Element Approach

Understanding of the wear behaviors between mechanical components is a significant task in engineering design. Finite element (FE) simulation may offer valuable wear information. However, longer computational time, poor data precision, and possible divergence of results are unavoidable in repetitive procedures, especially for large FE structures. To address these issues, the current method proposes a hypothesis that the strain energy is completely transferred through the contact regions of components; further that only variables on the contact surface are involved in the solution procedure. Our qualitative comparison demonstrates that the formulations in the current study are valid, offering significant implications for further application.

A Bi-Material Wedge – a Model for the Prediction of Failure Initiation at Shape and Material Discontinuities

2006 ◽  
Vol 324-325 ◽  
pp. 1305-1308
Author(s):  
Jan Klusák ◽  
Zdeněk Knésl
Keyword(s):  
Energy Density ◽  
Crack Initiation ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Stress Concentrations ◽  
Singular Stress ◽  
Failure Initiation ◽  
Density Factor ◽  
Material Discontinuities ◽  
Energy Density Factor

Geometrical and material discontinuities in constructions lead to singular stress concentrations and consequently to a crack initiation. The model of a bi-material wedge makes it possible to analyse such construction points to assess their stability. The presented approach is based on the knowledge of the strain energy density factor distribution in the concentrator vicinity.

A Finite Element Approach to the Transient Dynamics of Rolling Tires with Emphasis on Rolling Noise Simulation4

2007 ◽  
Vol 35 (3) ◽  
pp. 165-182 ◽  
Author(s):  
Maik Brinkmeier ◽  
Udo Nackenhorst ◽  
Heiner Volk
Keyword(s):  
Finite Element ◽  
Traffic Noise ◽  
Complex Eigenvalue ◽  
Arbitrary Lagrangian Eulerian ◽  
Finite Element Approach ◽  
Road Systems ◽  
Element Approach ◽  
Road Surface Roughness ◽  
Complex Eigenvalue Analysis ◽  
Rolling Noise

Abstract The sound radiating from rolling tires is the most important source of traffic noise in urban regions. In this contribution a detailed finite element approach for the dynamics of tire/road systems is presented with emphasis on rolling noise prediction. The analysis is split into sequential steps, namely, the nonlinear analysis of the stationary rolling problem within an arbitrary Lagrangian Eulerian framework, and a subsequent analysis of the transient dynamic response due to the excitation caused by road surface roughness. Here, a modal superposition approach is employed using complex eigenvalue analysis. Finally, the sound radiation analysis of the rolling tire/road system is performed.

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