Effect of SMC Lead Dimensional Variabilities on Lead Compliance and Solder Joint Fatigue Life

1992 ◽  
Vol 114 (2) ◽  
pp. 177-184 ◽  
Author(s):  
D. B. Barker ◽  
I. Sharif ◽  
A. Dasgupta ◽  
M. G. Pecht
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Three Dimensional ◽  
Finite Element Analyses ◽  
Surface Mount ◽  
Stiffness Matrices ◽  
Solder Joint Fatigue ◽  
Parametric Analyses ◽  
Three Dimensional Finite Element

Lead compliance is a critical parameter in optimal design and interconnection reliability of surface mount leaded components. The cyclic force transmitted to the solder joint in surface mount leaded components is controlled in part by the lead compliance. In this paper a methodology is presented for the computation of lead stiffness and the prediction of fatigue life of the leaded surface mount components. Three-dimensional finite element analyses have been performed to obtain the 12 × 12 stiffness matrices for both the PQFP gullwing and PLCC J leads and solder joints. These stiffnesses are then used in predictive fatigue life equations to estimate the fatigue life. The stiffness matrices and diagonal lead stiffnesses form the basis for identifying more failure resistant packages. Variabilities in lead and package dimensions provided by different vendors, manufacturing to JEDEC standards, are identified and their adverse effects on solder joint fatigue life are studied with the help of finite element parametric analyses. Eighty different finite element analyses are performed to study the effect of change in lead length, height, width and thickness on the lead stiffness and solder joint fatigue life for both the PQFP and PLCC attachments. Finally recommendations are made in order to obtain a better control on component fatigue life.

Mechanics Research with Prediction on the Fatigue Life of the Five-Cylinder Emulsion Pump Crankshaft

2013 ◽  
Vol 738 ◽  
pp. 163-166 ◽  
Author(s):  
Li Ran
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Working Conditions ◽  
Maximum Stress ◽  
Fatigue Crack Initiation ◽  
Three Dimensional ◽  
Finite Element Analyses ◽  
Mechanics Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, dynamic mechanics analysis was performed, in order to investigate the maximum forces acting on the crankshaft under working conditions. Then, three dimensional, finite element analyses have been conducted, in an attempt to predict the fatigue crack-initiation locations and lives. The maximum loadings, used in finite element analyses, were analytical obtained, which correspond to the five critical rotational angles of the first crankpin, i.e. = 40 º, 110º, 185 º, 255 º, 325 º. The maximum stress site was found to be approximately on the fillet of the first main journal of the crankshaft. The predicted fatigue life of the crankshafts was obtained by use of a stress-life (S-N) approach.

Gull-Wing Solder Joint Fatigue Life Sensitivity Evaluation

1997 ◽  
Vol 119 (3) ◽  
pp. 171-176 ◽  
Author(s):  
T. E. Wong ◽  
L. A. Kachatorian ◽  
B. D. Tierney
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Sensitivity Evaluation ◽  
Minimum Number ◽  
Parametric Studies ◽  
Solder Joint Fatigue ◽  
The Impact ◽  
Joint Assembly

A Taguchi design of experiment approach was applied to thermostructural analyses of a gull-wing solder joint assembly. This approach uses a minimum number of finite element analyses to evaluate the impact of solder joint assembly parameters on fatigue life of the assembly. To avoid costly complex modeling efforts for each parametric case study, a commercially available program, MSC/PATRAN’s PATRAN Command Language, was used to automatically create finite element models of a two-dimensional gull-wing solder joint assembly based on nine parameters. Modeling time was dramatically reduced from days to a few minutes for each detailed lead/solder model. Two sets of parametric studies were conducted to evaluate the impact of variation of the six parameters. The analysis results indicate that lead ankle radius is the most critical parameter affecting solder joint total fatigue life, and lead and minimum solder thicknesses are the next most critical ones. Therefore, to effectively improve the solder joint fatigue life margin, it is recommended to: (1) increase the minimum solder thickness; (2) use thinner lead; and (3) use a larger lead ankle radius, even though this may require reducing lead shin length. By implementing only the last recommendation to modify the current solder joint assembly, the fatigue life margin in this design could, in general, be improved by 27 percent or more.

Progressive fatigue behavior of single-lap bolted laminates under different tightening torque magnitudes

2020 ◽  
Vol 234 (10) ◽  
pp. 1303-1312
Author(s):  
M Feyzi ◽  
S Hassanifard ◽  
A Varvani-Farahani
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Behavior ◽  
Damage Model ◽  
Three Dimensional ◽  
Bolted Joints ◽  
Element Analysis ◽  
Damage And Failure ◽  
Experienced Fatigue ◽  
Three Dimensional Finite Element

The present paper studies fatigue damage and life of single-lap bolted joints tightened with different torque magnitudes subjected to uniaxial load cycles. The adherends were constructed from E-glass/epoxy layers using a hand layup technique and assembled by 1.5, 3, and 8 N m of applied torques. Increasing the torque magnitude benefitted the final fatigue life of the joints so that the high-cycle fatigue life of the joint sample tightened with 8 N m was as high as 10 times that of the joint tightened with 1.5 N m. In the numerical section of this study, a three-dimensional finite element analysis was employed, and the impacts of applied torques were included in the progressive damage model to assess damage and failure in the bolted joints. For the joints tightened with higher torque levels, numerical results revealed higher fatigue lives but at the cost of more delamination at the vicinity of the hole. Laminate fracture surface was investigated through scanning electron microscopy and more cracking/damage progress was evidenced in matrix, fiber, and matrix–fiber interface as composite joints experienced fatigue cycles. Experimental life data of tested joints agreed with those anticipated through the use of finite element analyses indicating the developed model as an appropriate tool in evaluating the effects of applied torques on the fatigue fracture behavior of bolted laminates.

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