Squeal Noise Improvement by High Damping & High Stiffness under Layer Material

This research focused on damping characteristics of Under Layer (UL) material to improve squeal noise performance. The study clarified that the raw material orientation causes anisotropy in dynamic viscoelasticity, especially with high damping and high stiffness UL material. Also, the loss modulus value, which is the damping element of dynamic viscoelasticity, corresponds with the raw material orientation and it is effective for damping for bending vibration. As a result, by using high damping and high rigidity UL material, the pad damping ratio was increased which leads to improved squeal noise.