A practical way to apply a technique that accelerates time history analysis of structures under digitised excitations

Abstract

Time history analysis using direct time integration is a versatile and widely accepted tool for analysing the dynamic behaviour of structures. In 2008, a technique was proposed to accelerate the time history analysis of structural systems subjected to digitised excitations. Recently, this technique has been named as the SEB THAAT* (Step-Enlargement-Based Time-History-Analysis-Acceleration- Technique), and the determination of appropriate values for its parameter is introduced as the main challenge. To overcome this challenge, a procedure is proposed in this paper. The basis of the procedure is the comments on accuracy control in structural dynamics and numerical analysis of ordinary differential equations, legalised in the New Zealand Seismic Code, NZS 1170.5:2004. As the main achievement, by using the proposed procedure, we can apply the SEB THAAT and carry out the time history analysis clearly and with less parameter setting compared to the ordinary time history analysis. The proposed procedure is always applicable and, except when the behaviour is very complex, oscillatory and non-linear, the reductions in analysis run-time are considerable while the changes in accuracy are negligible. The performance can be sensitive to the problem, the integration method, the target response, and the severity of the nonlinear behaviour. Compared to the previous tests on the SEB THAAT, the efficiency of applying the SEB THAAT using the proposed procedure is better, the sensitivity of the performance to the problem is lower, and a measure of accuracy is available. Compared to other techniques for accelerating structural dynamic analyses, the use of the SEB THAAT according to the proposed procedure has several positive points, including the simplicity of implementation.