A Damage Mechanics-Based Fatigue Life Prediction Model for Solder Joints

Abstract

A thermomechanical fatigue life prediction model based on the theory of damage mechanics is presented. The damage evolution, corresponding to the material degradation under cyclic thermomechanical loading, is quantified thermodynamic framework. The damage, as an internal state variable, is coupled with unified viscoplastic constitutive model to characterize the response of solder alloys. The damage-coupled viscoplastic model with kinematic and isotropic hardening is implemented in ABAQUS finite element package to simulate the cyclic softening behavior of solder joints. Several computational simulations of uniaxial monotonic tensile and cyclic shear tests are conducted to validate the model with experimental results. The behavior of an actual ball grid array (BGA) package under thermal fatigue loading is also simulated and compared with experimental results.

A computational damage mechanics model for thermomigration

“…Damage mechanics establishes fundamental principles for prediction of fatigue life of solid structures. A thermodynamic based formulation Basaran and Nie, 2004;Gomez and Basaran, 2005;Tang and Basaran, 2001;Gomez and Basaran, 2006;Tang and Basaran, 2003) has been proposed by Basaran et al and has been successfully implemented for low cycle fatigue failure of solder joints and particle filled composite. This is a model based on thermodynamics and continuum damage mechanics and it uses entropy production rate as damage metric.…”

A Model of Mechanothermodynamic Entropy in Tribology

“…A damage evolution model based on thermodynamic theory was developed by Basaran et al [25][26][27][28][29][30][31][32][33][34]. According to this model irreversible entropy production rate under loadings of different nature is …”

An Entropy-Based Damage Characterization

“…Basaran et al [36][37][38][39][40][41]] introduced a damage model described in terms of entropy on the basis of the second law of thermodynamics. They quantified the entropy generation and invoked the Boltzmann statistical entropy to define the isotropic damage evolution function for the eutectic Pb/Sn solder alloys.…”

“…Entropy can be used in a fundamental way to quantify degradation, including tribological processes such as friction and wear [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Similarly, other forms of degradation such as fretting [28] and fatigue damage of materials are consequences of irreversible processes that tend to increase the entropy generation of in the material [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. Dissipative processes can be directly linked to thermodynamic entropy, or associated thermodynamic energies, for example plasticity, dislocations [7,46], erosion-corrosion [9], wear-fracture [47,48], fretting-corrosion [49], high current density, thermal gradient, stress gradient and chemical gradient [50,51], thermal degradation, and associated failure of tribological components.…”