Dynamic PSD Random Vibration Analysis of an Electronics Cabinet

The behaviour of an electronics cabinet was investigated when subjected to dynamic loads. Modal analysis was used to assess the risk of any dynamic excitation from the surrounding structure. Response analysis was then conducted to calculate displacement and stresses due to random loading over a frequency range.

Finite Element Model

• All major frame members were included to accurately represent the cabinet stiffness
• Mass of electronics equipment was accounted for
• Cabinet mount points represented using spring elements with appropriate stiffness

Modal Analysis

• Involved undamped free vibrations of the cabinet
• Major modes predicted by checking the mass content of individual modes. High mass content in a direction indicates that mode will be excited by forces in that direction and generate a significant response
• Cumulative mass of all modes determined to ensure all major modes calculated

Response Analysis

• A statistical representation of the load history at mounts provided in the form of a Power Spectral Density (PSD)
• A PSD input was applied to the ground side of the spring elements
• Damping levels correlated with supplied data
• Displacement and stress RMS responses were calculated