Wei Yintao

Prediction of the 3-D effective damping matrix and energy dissipation of viscoelastic fiber composites

Abstract A new method for calculating the viscoelastic damping matrix of fiber composites is presented in this paper. Firstly, on the lamina scale, the energy dissipation formula is obtained by using a damping matrix and the theory of linear anisotropic viscoelasticity. Then on the laminate scale, a 3-D effective damping (loss) matrix is obtained by using the energy method. In terms of the 3-D effective damping matrix, the laminate energy loss and specific damping capacity (SDC) can be calculated by using the effective stresses and strains. The key to the application of the method lies in the derivation of the effective damping matrix from the constituent lamina damping coefficients, stiffness coefficients and volume fraction and the laminate effective stiffness and compliance coefficients. Based on the effective damping matrix method, the energy loss of viscoelastic fiber composites under arbitrary loading conditions can be calculated. This method has the advantages of generality, simplicity and directness. Several numerical examples are given to illustrate the accuracy of the model.

Indirect tire pressure monitoring system based on tire vertical stiffness

According to the tire inflation pressure changes leading to tire vertical stiffness variation, formulas including tire inflation pressure, load, rolling radius and tire footprint width are deduced. And determine wheel speed sensor numerical value as the critical parameter of predicting tire pressure change. The tire pressure monitoring test is designed and carried out, and the correctness of the algorithm is verified by data analysis.