MODELING SOLDER JOINT FATIGUE LIFE FOR GULLWING LEADED PACKAGES .1. ELASTIC-PLASTIC STRESS MODEL

It is a challenge to assess solder joint fatigue life in the modem ele ctronics industry because of complex geometries, complex non-linear vi scoplastic material properties, and the frequently changing environmen tal conditions. The first step in the fatigue life assessment process is to find the stress distribution in the solder. Traditionally, this has been done using numerical tools like finite element methods. The f inite element approach requires a highly trained and experienced analy st and huge computing resources, while the accuracy is always question ed. This study aims to develop a more accurate analytical-cum-empirica l model to predict critical stresses in the solder joint so as to avoi d the necessity of finite element simulation This paper presents a gen eric elastic-plastic stress model that is obtained based on theoretica l stress analysis solutions that is tweaked by using a design of exper iments technique with FEA simulations.