Printed circuit boards (PCBs) are important modules which are incorporated in a wide range of industrial equipment and machinery for the purpose of control or signal manipulation applications. PCBs situated in dynamic environments may be prone to failure from excessive amounts of cyclical stresses arising from harmonic or random vibration sources. The ability to numerically model and predict the dynamic behaviour of PCBs and associated components is therefore a valuable tool for analysts concerned with PCB reliability. In this paper, experimental vibration analysis and the finite element method (FEM) are used to investigate the changes in resonant behaviour of a PCB as the mass, location and stiffness of electronic components vary. Circuit boards that are either sparsely or densely populated with ubiquitous soldered electronic components such as resistors, transistors, capacitors and integrated circuits are considered. The analysis indicates that for boards with a small number of components the natural frequency decreases compared to that of the bare PCB whilst a board with a larger number of soldered components has a corresponding increase. It is also shown that the overall effect of the solder is to reduce the natural frequency of the PCB and to a lesser extent the damping ratio. The study identifies the potential of tailoring the vibration response of a PCB by the appropriate selection and location of its connected components.
EXPERIMENTAL AND NUMERICAL VIBRATION ANALYSIS OF PRINTED CIRCUIT BOARDS
