Nonlinear Dynamic Finite Element Analysis of Frames and Convergence Study

• Main Authors: Shun-Quan Tsai, 蔡舜全
• Other Authors: Ching-Jong Wang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/00761983623735999984

碩士 === 國立高雄第一科技大學 === 營建工程所 === 91 === The current seismic design of rigid frame structures usually involves linear analysis under reduced seismic loading, on condition that structure ductility be effected to bring about inelastic energy dissipation. Hence, the structure members have to meet certain ductility criteria. To evaluate the effectiveness of ductility design, it then becomes necessary to model the inelastic behavior of structural members accurately. Although the lumped plastic hinge model is relatively easier to use, it still lacks an adequate description for the redistribution of plastification along each member length. In this study, the stiffness matrix of each member is formulated by using virtual work principle taking into account the material nonlinearity. The nonlinear dynamic analysis procedure adopts the Newmark time integration in conjunction with the modified Newton-Raphason iteration. Several rigid frames are analyzed to illustrate the accuracy of above procedure and a finite element code written on this basis. All members of the frame are meshed into elements until convergence. The tangent stiffness and internal force of each element is determined according to the stress-strain state of each cross sections at element’s Gauss integration points; therefore, the redistribution of plastification is followed through. Regardless of the structure member types, steel, RC, or CFT, once the moment-curvature relationship and hysteresis loop of cross sections are defined, the procedure is ready to carry out a full-scale nonlinear dynamic analysis.