Study of Brake Pad Shim Modification to Improve Stability Against High Frequency Squeal Noise by Finite Element Analysis

This research studying on brake pad shim design with 4 configurations to improve the brake squeal noise phenomenon for high frequency noise in the range of 4-16 kHz. Various shims were designed with different configurations to increase structural damping and avoid instabilities in a brake system, which arise from friction drawing the vibration modes to coalesce between brake disc and brake pads. Then, the suspect brake module was tested in the laboratory using a dynamometer machine to confirm brake frequency noise parameters and conditions. The numerical models including brake disc, brake pad and brake pad shim were created using finite elements software and the unstable modes analysed for negative damping and positive real part values with the Complex Eigenvalue Analysis (CEA) technique. The simulation result showed that the instability of the brake system comes from mode coupling of the brake disc and brake pads in the out-of-plane modes (11ND) and (2 ND), respectively. The brake pads shim design1, design2 and design3 are component which goes in between the calipers and brake pads, were able to avoid high frequency brake squeal but make the noise move toward the direction of the lower frequency. The brake pad shim design4 is the good structure modification to avoid high frequency brake squeal and low frequency

Identification of Flexural Modulus and Poisson’s Ratio of Fresh Femoral Bone Based on a Finite Element Model

Finite element analysis (FEA) is increasingly applied to medicine because it could increase accuracy and rapid outcomes. However, there is a lack of the method to determine Young’s modulus and Poisson’s ratio for fresh femoral bone and the mathematical principle’s optimization for calculating nonuniform configuration. This study aimed to investigate the surrogate model for the optimization method to determine Young’s modulus and Poisson’s ratio of the fresh femoral bone. Young’s modulus and Poisson’s ratio obtained 20 ranked pairs by the Latin hypercube sampling method. The values ​​were calculated in the finite element for root mean square error (RMSE) and were then used for solutions by a quadratic function, radial basis function (RBF), and Kriging (KG). The lowest RMSE value was 0.1518 for the RBF method, with the young’s modulus at 304.4756 and the Poisson’s ratio at 0.3334. The current study identified the RBF technique to determine the properties of the femoral bone. Moreover, the RBF procedure might apply to other long bones because of the comparable nonuniform configuration