Efficient Simulation Methodology for Caliper Rattle Noise Based on a Reasonably Simplified Model and Integrated NVH CAE Approach

<div class="section abstract"><div class="htmlview paragraph">Brake caliper rattle noise is difficult to simulate due to its non-stationary, random, and broadband frequency characteristics. Many CAE engineers have adopted rattle vibration as an alternative metric to quantitative noise levels. Previous rattle noise simulations primarily presented relative displacement results derived from normal mode analysis or vibration dB levels rather than actual noise dB levels. However, rattle noise consists of continuous impact noise, which must account for reflections, diffractions, and refractions caused by transient nonlinear contacts and localized vibrations—especially during extremely short contact events. To accurately simulate impact noise, vibration and acoustic characteristics should be analyzed using a simplified structure, given the numerous mechanisms influencing impact noise generation. The rattle noise can be effectively modeled using LS-Dyna, which incorporates both explicit and BEM solvers. The correlation between test results and CAE simulations was established using a simple beam rattle model and a caliper system-level model, ensuring compliance with automotive manufacturer test specifications. A reasonably simplified FE model for rattle noise was developed to optimize computational efficiency and validated against previous complex eigenvalue analysis, explicit transient dynamic analysis for squeal noise (representing high frequencies), and explicit transient dynamic analysis for creep-groan vibration (representing low frequencies). This validation confirmed strong system-level correlation with vehicle and dynamometer test results. Finally, caliper system-level rattle noise simulations, utilizing the same validated squeal and creep-groan models, were conducted under Belgian road power spectral density conditions. Employing a single CAE tool and a unified FE model provides an efficient NVH engineering approach for identifying countermeasures during vehicle development. This study presents a practical example of an efficient CAE methodology for addressing brake NVH challenges.</div></div>