IMPROVED TIME INTEGRATION FOR PSEUDODYNAMIC TESTS

Converting the second-order differential equation to a first-order equ ation by integrating it with respect to time once as the governing equ ation of motion for a structural system can be very promising in the p seudodynamic testing. This was originally found and developed by Chang .(1-3) The application of this time-integration technique to the Newma rk explicit method is implimented and investigated in this paper. The main advantages of using the integral form of Newmark explicit method instead of the commonly used Newmark explicit method in a pseudodynami c test are: a less-error propagation effect, a better capability in ca pturing the rapid changes of dynamic loading and in eliminating the ad verse linearization errors. All these improvements have been verified by theoretical studies and experimental tests. Consequently, for a sam e time step this time-integration technique may result in less-error p ropagation and achieve more accurate test results than applying the or iginal form of Newmark explicit method in a pseudodynamic test due to these significant improvements. Thus, the incorporation of this propos ed time-integration technique into the direct integration method for p seudodynamic testings is strongly recommended. (C) 1998 John Wiley & S ons, Ltd.