Dynamics Of Board-Level Drop Impact

Abstract

The dynamic response of the printed circuit board (PCB) in a standard board-level drop impact test has been modeled as a spring-mass system, a beam, and a plate. Analytical solutions for the time-response and amplification of the deflection, bending moment, and acceleration at any point on the PCB have been developed and validated with finite element analysis. The analyses have shown that (i) the response of the PCB was dominated by the fundamental mode and (ii) the response of the PCB depends heavily on the ratio between the frequency of the PCB and the input acceleration pulse. The bending moment on the PCB has been shown beyond doubt to be responsible for the interconnection stress; the maximum moment on the PCB can be most effectively reduced through reducing the PCB thickness. The rapid receding of the higher modes in the moment response suggests that it can be adequately and effectively modeled using the standard implicit time-integration code.