Computing of Nonlinear Damping Using the Moving Autoregressive Model Method
Strictly speaking, internal damping of alloy materials is a function of temperature, frequency, strain and strain time rate and so on. Most of the previous papers with regard to damping computing only give a volumetric average when the alloy material is subjected to alternative stress. They cannot accurately describe the natural characteristic of damping. In this paper, the moving autoregressive model method (MARM) is presented to research the relationship between loss factor, strain and frequency of the alloys (Al-33Zn-6Si and Zn-27Al-1Cu). The experimental results show that the loss factor of alloy increases with the increasing strain, and increases with the increasing frequency in low-frequency region (below 400Hz). The damping appears strong nonlinear behavior. The three-dimension graph of the loss factor versus strain and frequency provides useful information for the optimum design of machine parts made from damping alloy.