INTEGRATION METHODS FOR IMPROVED STABILITY AND ACCURACY OF HYBRID SIMULATIONS
Two novel implementation methods of implicit integration procedures for hybrid simulation are presented. The first solves the equation of motion using a fully implicit iterative formulation. The experimental restoring force for each iterative displacement is estimated from curve-fitting of recent force-displacement measurements, avoiding physical iterations on the experimental substructures. For steps that do not converge, the procedure defaults to an explicit formulation. The second integration procedure is a modified operator-splitting integration scheme with two enhancements: a new formulation for the prediction phase with improved accuracy, and the use of an estimated tangent stiffness matrix of the experimental substructure to improve the accuracy of the correction step. A procedure for estimating the experimental tangent stiffness matrix is presented; it is updated only in the steps with significant displacement increments, and remains unchanged otherwise to ensure that the quality of measured data is reliable. Both integration procedures have been successfully implemented experimentally and shown to improve the stability and accuracy of hybrid simulations. Numerical and experimental simulations demonstrate the effectiveness of these integration schemes, especially in utilization of longer time steps, prevention of excitation of higher modes, and testing of stiff and highly nonlinear systems. Improvements in accuracy are demonstrated by measuring the energy balance in the equation of motion.
Hybrid simulation Numerical integration Implicit integration Tangent stiffness
G. Mosqueda M. Ahmadizadeh
University at Buffalo, the State University of New York, USA Department of Civil Engineering, Shiraz University, Shiraz, Iran
国际会议
14th World Conference on Earthquake Engineering(第十四届国际地震工程会议)
北京
英文
2008-10-12（万方平台首次上网日期，不代表论文的发表时间）