Application of Orthogonal Functions to Equivalent Linearization Method for MDOF Duffing–Van der Pol Systems under Nonstationary Random Excitations

Many mechanical systems manifest nonlinear behavior under nonstationary random excitations. Neglecting this nonlinearity in the modeling of a dynamic system would result unacceptable results. However, it is challenging to find exact solutions problems. Therefore, equivalent linearization methods are often used seek approximate for kind problem. To overcome limitations existing methods, an orthogonal-function-based method time domain proposed subjected The first applied single-degree-of-freedom (SDOF) Duffing–Van der Pol oscillator stationary and excitations validate its accuracy. Then, applicability MDOF depicted by 5DOF excitation, with different levels strength considered analysis. Results show that has merit predicting response high accuracy computation efficiency. In addition, applicable any general type excitation.