Advanced Diagnostics Simulations Approach For Random Response Analysis To Analyse Road NVH Characteristics

Traditionally, simulation-based approach for solving Road NVH issues using random response analysis (non-deterministic excitations) suffered from lack of formulations and methodologies to perform diagnostics like modal contribution, transfer path analysis, etc. in contrast to deterministic analysis. This greatly restricted simulations usage and contribution in resolving road NVH issues during design phase and postponed most of the road NVH development work till late in the testing phase. This paper shows collaborative and efficient way of handling test data of measured road surface in full vehicle CAE simulations to predict vehicle NVH responses using random response analysis and further diagnostics using advanced mathematical formulations. Experimentally measured road surface is converted into Power Spectral Density (PSD) using signal processing methods. These processed PSDs are applied as enforced displacements to the tire contact patch points in full vehicle CAE model for prediction of vehicle NVH responses using Random Response Analysis. While applying the PSD excitations, the effects of interactions between tires of the vehicle are also considered. An elaborate study is conducted to understand the effects of vehicle speed, road conditions and vehicle structural dynamics on the NVH characteristics. This paper also describes novel methodology for assessing modal contribution, panel participation and transfer path analysis for random excitations allowing further evaluation and diagnostics of road NVH issues. Detailed correlation of CAE results with test results are presented and discussed to show the validity of the process.