Inclusion of higher modes in the analysis of non‐classically damped systems

Abstract

Abstract A time‐integration procedure for dynamic analysis of non‐classically damped systems, in which high‐frequency modes play a significant role, is suggested. This procedure is an extension of Clough and Mojtahedi's 1 method. Clough and Mojtahedi suggested integration of the transformed coupled equations of motion where the transformation is done using a truncated set of undamped mode‐shapes. The proposed extension consists in adding the response of all the higher modes through a quasistatic analysis. Approximations involved in using such a procedure are examined. Numerical results presented indicate that the proposed extension leads to a significant improvement over Clough and Mojtahedi's method.