Zahra Pachenari - Department of Civil Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran
Alireza Pachenari - Department of Civil Engineering, University of Kashan, Kashan, Iran

The finite element method changes the systems with unlimited degrees of freedom to a model with limited degrees of freedom (DOFs), which has a similar physical behavior. The one-dimensional generalized subspace (ODGS) method presents a proper solution to the analysis of nonlinear dynamic problems with Ritz-Wilson vectors. It could be used as a reduction method that transforms DOFs to a much more limited number in a new coordinate. In this paper the ODGS method has been used in combination with modeacceleration technique, to analyze nonlinear dynamic problems. With emphasis on inside error component, a modification criterion using the mode-acceleration technique is suggested for updating thebase vectors required in stiffness changes in nonlinear dynamic analysis. Numerical examples show the suitability of the proposed method in both economy and exactness

Nonlinear dynamic analysis, Numerical analysis, Ritz vector, Reduction method