Finite Element Analysis of Printed Circuit Boards Using Isotropic Elastoplastic Model and Application to Drop Simulation for Mobile Phone

Abstract

Flexural behavior of printed circuit boards (PCB) is well known for the major failure mechanism under board level or product level mobile phone drop tests. This behavior induces high peeling stress between PCB and IC package. This stress causes failure including both solder joint crack and pad cratering, which leads to malfunction such as phone dead or power off. Therefore, for a more reliable mobile phone design, it is important to accurately predict behavior of the PCB. In the past, isotropic or orthogonal linear elastic model have been used for simulating PCB in finite element analysis. Also, since PCB consists of multiple layers with woven glass fiber epoxy resin composite (FR-4) and copper foils, a multilayered PCB model was developed in order to consider material properties that change along the different plies. In this paper, the isotropic elastoplastic model was employed in order to efficiently predict behavior of PCB. Tensile and flexural test of PCB were conducted initially to evaluate mechanical characteristics and obtain representative material properties. Then, simulation of flexural test was performed to develop the finite element modeling. Finally, a drop test of mobile phone adopted with PCB bare board, which did not include IC packages, was examined. Also, the strain gage was used for measuring strain of PCB. This result was compared with drop simulation results of mobile phone, which used finite element modeling suggested. In conclusion, from an industry standpoint, finite element modeling of PCB using isotropic elasoplastic model was useful and efficient.

Failure Mechanism of the Fire Control Computer CPU Board inside the Tank under Transient Shock: Finite Element Simulations and Experimental Studies

“…Liu [ 8 ] proposed the methods of parameterized substructure modeling and PCB equivalent density modeling, which can greatly improve the simulation efficiency. Jeon et al [ 9 ] built an isotropic elastoplastic FEM model for cell phone circuit boards and carried out both simulations and experiments with drop impact. Shtennikov and Budai [ 10 ] analyzed the circuit board welding points failure under vibration and proposed an effective improvement method.…”