Characterization of boundary conditions for wedge-lock-mounted printed circuit boards

Abstract

Vibration testing and analysis is becoming increasingly important in the electronics industry. It is used as a workmanship screen, as well as a way to duplicate the deployed environment in both the military and commercial avionics worlds. To minimize the effects of the vibration from testing and what will be encountered in service, the mechanical analyst must be able to accurately predict mode shapes and frequencies of in-situ PC board.

This thesis will investigate modeling the wedge locks as non-uniform translational and rotational springs. The first eight natural frequencies of a rectangular circuit board (with no components soldered to it, and with wedge locks along two edges) will be empirically determined. Eight frequencies will be used to solve for four unknowns: continuously distributed translational and rotational spring stiffnesses along the segments of board that are in contact (two unknowns) with the wedge lock, and those that are not in contact (two unknowns). A finite element model will be developed of the physical system. The translational and rotational spring stiffnesses will be optimized to minimize an error function involving the difference between the empirical and analytically predicted natural frequencies.