Effect of Edge and Internal Point Support of a Printed Circuit Board Under Vibration

Abstract

This paper presents an investigation into the vibration of a PCB that is supported on its three edges by two wedge retainers and a plug-in connector. Using a vibration test fixture to couple the PCB structure to an electromagnetic shaker, experiments were conducted to determine its dynamic response. The wedge retainer and connector are modeled as simply supported condition with appropriate rotational spring stiffnesses along their respective edges. It is found that these supports behave somewhere between the simply supported and clamped boundary conditions and provide a percent fixity of 39.5 percent more than the classical simply supported case. It is further found that a single internal point constraint that would yield the maximum fundamental frequency is located at the intersection of the nodal lines of mode 2 and mode 3. This has the effect of significantly increasing the PCB’s fundamental frequency from 68.4 Hz to 146.9 Hz, or 115 percent higher.