An Algorithm of Generating Consistent Stiffness Matrices for Incremental Analysis of Elastic-plastic structures

Research Project

Project/Area Number	07650661
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Building structures/materials
Research Institution	Kyoto Institute of Technology
Principal Investigator	MORISAKO Kiyotaka Kyoto Institute of Technology, Faculty of Engineering and Design, Associate Professor, 工芸学部, 助教授 (90127168)
Project Period (FY)	1995 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
Keywords	elastic-plastic / incremental analysis / consistent stiffness matrix / Shanley model / degrading material / recurrent selecting process / comparison spring / determinant / ひずみ軟化 / 固有値 / バイリニア劣化型ばね
Research Abstract	In the incremental analysis of the critical behavior of an elastic-plastic structure, a conventional iterative procedure for finding the set of element stiffness coefficients consistent with the material flow law may often lead to a pitfall of cyclic process, in which a multiple in consistent sets of stiffness coefficients are to be alternately or recurrently selected. This is one of the most serious difficulties left unsolved in combined nonlinear analysis. In this study, the intrinsic mechanism and characteristics of these cyclic processes are clarified for a simple rigid body-spring column model called Shanley model. On the basis of the results, an effective strategy for finding the consistent set is proposed with the use of the eigenvector associated with the smallest negative eigenvalue of system stiffness matrix as the comparison body.