Parametric Modal Study of Multilayer Composite Electronic Boards
Printed circuit boards made of composites in working environments such as avionics or transportation are susceptible of structural failure or irreversible damage under the vibration of the equipment. Structural modal/harmonic finite element models in ANSYS are integrated in this study to enable the predictions of resonance frequency shifts and failure stress for vertically clamped parallel circuit boards with inclusion of series of mounted electronic modules (chips). The board is modeled as a thin plate made of layers of Eglass composite with different fiber orientations and inter-fiber angles. Appreciable differences in maximum failure stress and resonance frequency shifts are observed by changing the above parameters in the fabrication of the boards. Mathematical approximations (metamodels) are provided to describe the complex trend of resonance frequencies in terms of angular design parameters. The model equations would simplify the parametric effects on frequency shifts and provide insight into any subse nt design optimization in the absence of access to FE codes, or readiness to devote more resources on FE analysis. Overall this study presents feasible ANSYS models that render successfully an optimal design for composite circuit boards under vibration loads, and without weight increase by modifications or material additions. This would lead to board designs that are more durable and reliable under noise, shock, and vibration loads.
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