Vibration Induced Fatigue Life Estimation of Corner Leads of Peripheral Leaded Components

1996 ◽  
Vol 118 (4) ◽  
pp. 244-249 ◽  
Author(s):  
Sidharth ◽  
D. B. Barker
Keyword(s):  
Fatigue Life ◽  
Integrated Circuits ◽  
Analytical Techniques ◽  
Electronic Packages ◽  
Element Analysis ◽  
Thermally Induced ◽  
Operating Environments ◽  
Fatigue Life Estimation ◽  
Out Of Plane ◽  
Plane Displacement

The rapid advancement of integrated circuits and associated electronic technologies have placed increasing demands on electronic packaging and its material structures in terms of the reliability requirements. In addition to the thermally induced stresses, electronic packages often experience dynamic external loads during shipping, handling, and/or operation. This is especially important for automotive, military, and commercial avionics operating environments. These dynamic loads give rise to large dynamic stresses in the leads causing fatigue failures. For peripheral leaded packages the corner leads are the most highly stressed leads. This paper addresses the determination of the out-of-plane displacement of the corner leads of peripheral leaded components when the local peripheral leaded component/board assembly is subjected to bending moments in two directions. The solution is achieved by using a combination of Finite Element Analysis (FEA), Design of Experiments (DOE), and analytical techniques. The out-of-plane displacement can then be applied as a boundary condition on a local lead model to determine the stresses which in turn can be used to estimate the fatigue life.

scholarly journals Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Jungwon Huh ◽  
In-Tae Kim ◽  
Jin-Hee Ahn
Keyword(s):  
Corrosion Damage ◽  
Element Analysis ◽  
Buckling Strength ◽  
Lower Shear ◽  
Out Of Plane ◽  
Shear Buckling ◽  
Buckling Failure ◽  
Plane Displacement ◽  
The Web ◽  
Plate Girder

The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

Warpage of Flip Chip BGA Package

2006 ◽  
Author(s):  
Milena Vujosevic
Keyword(s):  
Flip Chip ◽  
Plate Theory ◽  
Contour Plot ◽  
Thermally Induced ◽  
Ball Grid Arrays ◽  
Fundamental Understanding ◽  
Out Of Plane ◽  
Bga Package ◽  
Plane Displacement ◽  
Analytical Expressions

The work focuses on the thermally induced out of plane displacement of Flip Chip Ball Grid Arrays (FCBGA). Analytical expressions for substrate displacements are derived based on the Plate Theory and Suhir's solution for stresses in tri-material assembly. The validity of the model is established by comparing the analytical solution to the finite element results as well as to the experimental data. The benefits of the model are twofold: 1) it provides a tool for fundamental understanding of the parameters that influence warpage, and 2) has a predictive capability. With respect to 1) an analysis is presented on the nature and degree of influence that different geometric and material parameters have on the FCBGA warpage. With respect to 2) the "Warpage Contour Plot" is proposed as a tool for warpage prediction that can be easily utilized in the early stages of the design process.

Warpage Measurement Using Projection Moire´ System and Two Automatic Image Segmentation Algorithms

2007 ◽  
Author(s):  
Wei Tan ◽  
I. Charles Ume
Keyword(s):  
Image Segmentation ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Segmentation Algorithms ◽  
Out Of Plane ◽  
Cte Mismatch ◽  
Image Models ◽  
Wiring Board ◽  
Plane Displacement ◽  
Projection Moire

Out-of-plane displacement (warpage) has been a major reliability concern for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from CTE mismatch among the materials that make up the PWB assembly (PWBA). Warpage occurring during surface-mount assembly reflow processes and normal operations may lead to serious reliability problems. In this paper, a projection moire´ warpage measurement system and two types of automatic image segmentation algorithms were presented. In order to use the projection moire´ technique to separately determine the warpage of a PWB and assembled electronic packages in a PWBA, two image segmentation algorithms based on mask image models and active contour models (snakes) were developed. They were used to detect package locations in a PWBA displacement image generated by the projection moire´ system. The performances of the mask image and snake approaches based on their resolutions, processing rates, and measurement efficiencies were evaluated in this research. Real-time composite Hermite surface models were constructed to estimate the PWB warpage values underneath the electronic packages. The above automatic image segmentation algorithms were integrated with the projection moire´ system to accurately evaluate the warpage of PWBs and assembled chip packages individually.

Effect of Intermetallic Compounds on the Thermomechanical Fatigue Life of Three-Dimensional Integrated Circuit Package Microsolder Bumps: Finite Element Analysis and Study

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Soud Farhan Choudhury ◽  
Leila Ladani
Keyword(s):  
Fatigue Life ◽  
Integrated Circuits ◽  
Integrated Circuit ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Strain Range ◽  
Bulk Solder ◽  
Element Analysis ◽  
Plastic Strain Range ◽  
Inelastic Strains

Currently, intermetallics (IMCs) in the solder joint are getting much attention due to their higher volume fraction in the smaller thickness interconnects. They possess different mechanical properties compared to bulk solder. Large volume fraction of IMCs may affect the mechanical behavior, thermomechanical and mechanical fatigue life and reliability of the solder interconnects due to very brittle nature compared to solder material. The question that this study is seeking to answer is how degrading IMCs are to the thermomechanical reliability of the microbumps used in three-dimensional (3D) integrated circuits (ICs) where the microsolder bumps have only a few microns of bond thicknesses. Several factors such as “squeezed out” solder geometry and IMC thickness are studied through a numerical experiment. Fatigue life is calculated using Coffin–Manson model. Results show that, though undesirable because of high likelihood of creating short circuits, squeezed out solder accumulates less inelastic strains under thermomechanical cyclic load and has higher fatigue life. The results show that with the increase of IMCs thickness in each model, the inelastic strains accumulation per cycle increases, thus decreasing the fatigue life. The drop in fatigue life tends to follow an exponential decay path. On the other hand, it was observed that plastic strain range per cycle tends to develop rapidly in Cu region with the increase in IMC thickness which calls for a consideration of Cu fatigue life more closely when the microbump contains a higher volume fraction of the IMCs. Overall, by analyzing the results, it is obvious that the presence of IMCs must be considered for microsolder bump with smaller bond thickness in fatigue life prediction model to generate more reasonable and correct results.

Engine Crankshaft Remanufacturing Life Prediction and Experimental Verification

2011 ◽  
Vol 215 ◽  
pp. 263-271
Author(s):  
Guo Qing Zhang ◽  
Hai Bo Lin
Keyword(s):  
Fatigue Life ◽  
Damage Model ◽  
Local Stress ◽  
Fatigue Tests ◽  
Element Analysis ◽  
Fatigue Life Estimation ◽  
Before And After ◽  
Injury Models ◽  
Engine Crankshaft ◽  
Strain Method

In this paper, the engine crankshaft remanufacturing life was estimated before and after. As long as the known material properties, loading, local stress, and then select the appropriate fatigue damage model can predict the fatigue life estimation. Material parameters of the experiment and the approximate method are obtained; load is on the basis of dynamic simulation; local stress obtained by finite element analysis; injury models were selected: the uniaxial damage model S-N method and multi-axis model of damage is strain method, SWT-Bannantine method, shear strain method, Fatemi-Socie method. New crankshaft and 500 hours, 1000 hours and 3000 hours after the crankshaft bench fatigue tests were conducted, and the experimental results were compared to verify the correctness of the theoretical calculation, and explain the crankshaft to remanufacture the fatigue life is sufficient.

Transient Stress Analysis and Fatigue Life Estimation of Turbine Blades

2004 ◽  
Vol 126 (4) ◽  
pp. 485-495 ◽  
Author(s):  
Deepak Dhar ◽  
A. M. Sharan ◽  
J. S. Rao
Keyword(s):  
Fatigue Life ◽  
Thermal Stresses ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Element Analysis ◽  
Life Estimation ◽  
Start Up ◽  
Fatigue Life Estimation ◽  
Transfer Equations ◽  
Number Of Cycles

This paper is concerned with life estimation of a turbine blade taking into account the combined effects of centrifugal stresses, vibratory stresses and thermal stresses. The stresses are determined by accounting for the rotor acceleration. The blades are subjected to aerodynamic excitation force obtained from thin cambered aerofoil theory under incompressible flow. The thermo-elastic forces are obtained from the three-dimensional non-linear heat transfer equations using the finite element analysis. The fatigue life is estimated using two well known theories, from the number of cycles in various blocks during start-up and shut-down periods of the turbine operation when the stresses peak.

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