Application of Chang explicit method to Structural Dynamics

• Main Authors: Hung-Chi Peng, 彭泓淇
• Other Authors: 張順益
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/be3rec

碩士 === 國立臺北科技大學 === 土木與防災研究所 === 102 === Step-by-step methods are widely used in the solution of dynamic problems, and they are classified as implicit and explicit methods. Implicit methods can have unconditional stability, however, the involvement of an iteration procedure lead to computationally inefficiency. Although the calculation of each time step of explicit method is simple, it can only have conditional stability and thus a small time step may be required to meet stability conditions. Therefore, an ideal integration method would like to have explicit formulation and unconditional stability simultaneously. Since Chang explicit method can integrate these two properties together, it is adopted in this study. OpenSees is a finite element software, where the code was written by C++ language. In order to study the feasibility and computational efficiency of Chang explicit method, its computing procedure is implemented into OpenSees for the dynamic analysis. Consequently, many structural dynamic problems are solved by Chang explicit method. The structural systems considered herein may be linear elastic or nonlinear. In addition, the structural nonlinearity includes both material nonlinearity and geometric nonlinearity. Both the Newmark explicit method and the constant average acceleration method are also used to solve all the structural dynamic problems for comparisons. As a result, the feasibility of using Chang explicit method to perform any dynamic analysis is verified. In addition, it is evident from the comparison of CPU time for each dynamic analysis that Chang explicit method is computationally efficient in the solution of an inertial type problem when compared to the Newmark explicit method and the constant average acceleration method.