Modeling of printed circuit cards subject to vibration

Some of the current methodologies used in modeling printed circuit cards subjected to vibration are introduced. An overview of experimental and computational methods of determining the natural frequencies and mode shapes of circuit cards populated with various module types is presented. Methodologies for correlating experimentally derived vibration data with the computer models are explored. By using the modal assurance criterion as a correlation measure, it is shown that smearing or homogenizing the material properties is effective in preserving a good degree of correlation in the lower modes of vibration of an example printed circuit card. It is also observed that modeling the entire card as a single composite modeling region is surprisingly effective. However, increasing the number of composite modeling regions to five produced a better overall correlation of the modes of interest.