Non-intrusive identification of anisotropic elastic constants of friction materials of disk brake pads using inverse analysis

Abstract

A novel method to identify anisotropic elastic constants for friction materials of automotive disk brake pads is proposed. This method identifies accurate elastic constants of friction materials in a non-intrusive way using the inverse analysis. To solve this inverse analysis, eigenfrequencies and mode shapes are measured with the hammering test. In order to make this problem well-posed, the original measurement system is developed. This new system reversibly constrains the sliding surface of the pad to the metal block using ice with refrigerating the metal block. Measured eigenfrequencies and mode shapes of the constrained pad make this problem well-posed. The Response Surface Method (RSM) is applied to reduce computational time of the eigenvalue analysis using FEM. In order to increase regression accuracy of response surfaces, the Modal Assurance Criterion (MAC) is applied to correlate measured and calculated mode shapes. Identification accuracy is performed with simulated measurement. Identification of elastic constants of an actual brake pad is performed. Calculation results are smoothly converged to reasonable values.

Keywords

• inverse analysis
• maximum likelyhood estimation
• brake pad
• anisotropic elastic constants
• response surface method
• modal assurance criterion