Vibration fatigue analysis and test verification of ODP bracket for new energy vehicle based on road spectrum equivalent conversion PSD

ObjectiveThis study aims to solve the fatigue cracking problem of integrated power management module (ODP) brackets in new energy vehicles during endurance testing by establishing a comprehensive vibration fatigue simulation and verification framework.MethodsLow-cycle strain fatigue behaviors of DC01 and B280VK materials were characterized using the Manson-Coffin-Basquin model. Time-domain acceleration road spectra were collected and accelerated into equivalent power spectrum density (PSD) based on the equivalent damage principle. Finite element models were constructed to analyze stress frequency response, and random vibration fatigue damage was calculated using Dirlik probability density functions and Miner's rule.ResultsThe results indicate that the initial design's maximum damage reaches 1.90, far exceeding the failure threshold of 1.0, with the predicted risk area matching the actual failure site. After structural reinforcement and material upgrading to B280VK, the maximum damage decreased to 0.10 and the fatigue safety factor increased to 10.0. The improved design successfully passed the 24 h accelerated bench test and 31 490 km vehicle road durability test without any visible fatigue cracks, confirming that the proposed method effectively mitigates vibration fatigue risks in the vehicle body domain.