This paper proposes a composite body solution (CBS) bracket method to balance the interior rumbling noise caused by the cowl with the adult head score for pedestrian protection. This method not only improves the interior noise level but also enhances the head score for pedestrian protection. Firstly, a comparison of the basic parameters and mechanical properties of CBS scaffold material and common metal materials reveals that CBS scaffold material has the advantages of low Young’s modulus and low yield strength. The sensitivity of adult head score for pedestrian protection to linear and nonlinear segments was distinguished according to the material’s mechanical property curve, indicating that the yield section has a higher impact on head injury. Secondly, the topology optimization method is used to obtain the initial CBS contour structure based on the main noise transfer function (NTF) contribution path of the vehicle roar noise, and the specific structure of the contour is refined. Finally, noise and pedestrian protection are verified for specific CBS structures. The results show that compared to the basic state, the roar noise from the Z-direction excitation of the right suspension to the driver’s external ear in the car is improved by 2 dB in 70 Hz to 80 Hz frequency band and about 3 dB in 150 Hz to 170 Hz frequency band, and the score for pedestrian protection is 1 points higher than the basic state. This method achieves a balance between noise reduction and pedestrian protection, verifying the feasibility of this method to resolve the conflict between noise and pedestrian safety.
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Supported by National Key R&D Program of China (2020YFB1709404).
