Effect of Backing PU Foam Material Properties on Acoustic Insulation Pad Insertion Loss

The effect of backing polyurethane (PU) foam material properties on the insertion loss of acoustic insulation pads was investigated. First, the material properties affecting the resonant frequency, which mainly determines the insertion loss, were theoretically identified, and practical methods for calculating both the resonant frequency and the insertion loss of the insulation pad were developed. These methods were then applied to evaluate how changes in material properties influence the resonant frequency and insertion loss of the insulation pad. It was found that Young’s modulus, Poisson’s ratio, and thermal characteristic length are the primary material properties that affect these outcomes. The optimal levels of these properties, which are beneficial for interior noise reduction, are derived and presented in this study.