On the Essentiality of Techniques to Enlarge Integration Steps in Transient Analysis Against Digitized Excitations

Soroushian, Aram; Farshadmanesh, Pegah; Azad, Soheil

doi:10.48303/jsee.2015.240706

On the Essentiality of Techniques to Enlarge Integration Steps in Transient Analysis Against Digitized Excitations

Document Type : Structural Earthquake Engineering

Authors

Aram Soroushian ¹

Pegah Farshadmanesh ²

Soheil Azad ¹

¹ IIEES

² Illinois Institute of Technology (IIT)

10.48303/jsee.2015.240706

Abstract

In transient analysis against digitized excitations, and specially, practical seismic analyses, the steps, by which, the strong ground motions are digitized, might be smaller than those recommended for the accuracy of integration. In these cases, in order to consider the total excitation information, the integration steps are to be set as small as the excitation steps. The result is extra computational cost. In the last decade, techniques are proposed, to provide the capability of time integration with larger steps, without disregarding the excitations information. Though the resulting responses are sufficiently accurate, a fundamental question persists. It is on the loss of accuracy, when we simply omit the inter-integration-step excitations. This paper is dedicated to this concern, in the area of seismic analysis. The study is carried out, through theoretical discussions and numerical examples. As the consequence, omission of inter-integration-step excitations may impair the responses, the inaccuracies can be significant, and even, halts of analyses are expectable, in nonlinear analyses. Implementation of techniques for enlargement of integration steps can lead to more efficient and more reliable analyses.

Keywords

Time integration

Digitized excitations

Ground Motion

Step size

Computational cost

accuracy