Development of a tunable test method for characterizing friction-induced squeak noise in automotive interior plastics

The emergence of low-noise vehicles, such as electric and hydrogen-powered cars, has increased the perceptibility of minor noises—commonly referred to as buzz, squeak, and rattle—which can significantly influence consumer perception and satisfaction. Among these, squeak noise arises from dynamic frictional interactions between contacting components and is highly sensitive to material properties and environmental conditions. However, existing commercial testing systems with fixed structural stiffness are inadequate for evaluating the friction-induced noise behaviors of various polymer combinations under diverse conditions. To overcome these limitations, a novel test apparatus was developed with adjustable system stiffness and frictional speed, alongside a corresponding evaluation methodology. This setup enables detailed analysis of friction-induced noise characteristics, including frequency, amplitude, and vibration acceleration level (VAL). Experiments were performed using three polymeric materials—polycarbonate (PC), polyoxymethylene (POM), and a polypropylene compound (PP-TDGX)—across four sliding speeds and four stiffness settings. A bandpass filter was applied to eliminate background noise from the acquired signals, and time-domain feature extraction was used to quantify the frequency and amplitude of friction-induced oscillations. Additionally, vibration analysis based on VAL was conducted to assess the severity of frictional noise. The results demonstrate that the tribological interactions between polymer pairs vary significantly with changes in sliding speed and system stiffness. The proposed testing method and equipment offer a more accurate and flexible approach to characterizing friction-induced noise in polymeric materials, thereby supporting more effective material selection for automotive interior applications and potentially reducing both noise issues and development costs.