Advancements in assessment & mathematical optimization for squeak phenomena

Refinement of vehicle noise and vibration levels has successfully evolved over the past few decades and significant attenuation in products is eminent across the automotive industry. Annoying noises like Squeak and rattle, therefore, have become more prominent in recent years and are increasingly being perceived as paucity of product quality. Squeak phenomena is generally more demanding to test, simulate and correlate mathematically. In this work, the effects of contact directional stiffness in the squeak's principal peak to peak (main directional displacement) at specific sensor (E-line) locations are tabulated. A method is necessitated to study the optimum preloading value for E-points in typical Instrument panel to achieve realistic principal peak to peak displacements. Relative modal contributions are mathematically calculated at time steps having maximum peak to peak relative displacements in x and y directions. Further, an optimization is performed at the selected E-points to reduce the top contributing modes in x and y direction. A mathematical objective function of weighted principal peak to peak displacements in targeted time range is formulated for the optimization.