An Experimental Analysis of Interior Noise in an Ambulance and Noise Reduction with Damping Materials

To solve the problem of an ambulance interior noise, a multi-input and single-output linear system model is established based on the partial coherence analysis method. In this model, vibration acceleration signals of panels are treated as input, sound pressure signals is treated as output. The relevant influence among the system inputs are ruled out and the partial coherence function value is considered as an indicator to estimate the panels’ acoustic contribution to the field point. On the basis of analysis, the structural modification with damping materials is performed on the panels with greater contribution. The results show that panels’ acoustic contribution can be analyzed by partial coherence analysis method effectively and structural modification with damping materials based on the method has significant effect on reducing the vehicle interior noise and decreasing additional mass.