Evaluation of Response Characteristics of Spaceborne Electronic Equipment Considering Mounting Boundary Conditions

In this study, the response characteristics of spaceborne electronic equipment under actual mounting boundary conditions were evaluated, and an equivalent contact stiffness-based modeling technique was proposed to compensate for the limitations of conventional boundary-condition-based analysis. Finite element analyses were performed for three configurations: an initial design, a structure with increased contact area, and a structure with added stiffeners. Random vibration tests were then conducted with accelerometers directly attached to the PCBs and housings under actual mounting conditions, and the results were compared with conventional analysis results. The conventional analysis overpredicted the actual responses for all configurations, showing discrepancies in response magnitude, housing bottom-surface behavior, and natural frequency distribution. These discrepancies were attributed to insufficient representation of the bottom-surface contact effect formed under actual mounting conditions. Therefore, an empirical equation for the equivalent contact stiffness was established by incorporating fastening force, effective contact area ratio, bottom-surface thickness, and effective span length, and implemented using CBUSH-element-based contact modeling. The proposed method improved the correlation between test and analysis results for all three configurations, demonstrating its applicability for reliable response prediction and overdesign reduction at the early design stage.