New test approach was suggested to evaluate the vehicle structure sensitivity relating with the low frequency noise during a braking. A miniature shaker (M-Shaker) was introduced as an alternative tool of the current complex tool which requires high cost and long test time in measuring vehicle structure sensitivity. Sound pressure level as a function of a frequency depending on excitation site, profile, force and location were compared to set up the optimized testing condition. Using the optimized test condition and tools, the vehicle structure sensitivity of the 5 different vehicles were measured. The results also compared with vehicle creep groan test result using the regression analysis. The results showed that the excitation of strut x direction or that of LCA(Lower Control Arm) x direction was not enough to represent noise characteristics, however the sum of excitation noise (LCA + strut) exhibited good correlation with the vehicle noise test results. It suggests that the new test method using a miniature shaker can be used as an effective tool to evaluate the vehicle structure sensitivity for low frequency noise(structure-borne).

Jae Cheol, Lee; Kyu Won, Yoon; Keun Hyung, Cho; Choon Ki, Park; - Mando Corp