Constrained polymer layers to reduce noise: reality or fiction?—An experimental inquiry into their effectiveness

The frequency and temperature dependent noise radiation properties of constrained polymer layered oil pans are examined through mobility and intensity measurements. Four metal/polymer/metal sandwich composites of varied thermo-plastic elastomer systems of polystyrene–polybutadiene–polystyrene triblock copolymers are investigated within a wide frequency range covering 1000–5000 Hz, and over a wide temperature range covering 20–100 °C, with results compared to those of an ordinary steel oil pan. The mobility and intensity are found to be strongly frequency and temperature dependent, displaying a substantial mobility reduction as compared to that of the ordinary pan, while using the constrained layer damping configurations at their maximum loss factor temperatures. However, the reduction of noise radiation is smaller than that of the mobility at those temperatures, mainly due to the increased radiation efficiency while adding damping materials.