Study Of Dynamic Arithmetic And Mechanical Characteristics For The Cable-Strut-Beam-Membrane Structure And Dynamic Programming

Cable-Strut-Beam-Membrane structure (CSBM) is accepted by more and more researchers for its novelty, ingenious idea and efficiencies. So it is applied in kinds of structures, and shows great vitality and applied future in great span. Lots of researchers have done lots of deep theory research for this special kind of structure. However it still remains in the field of form finding, static load analysis, wind-induced vibration, and there is less theory research in the dynamic characteristic.And talking of analyzing tools, researchers in the main land usually use some universal finite element softwares in analyzing the CSBM, such as ANSYS, SAP2000 and so on. Although these kinds of analyzing software owns good calculating efficiency and high calculating precision. But in ordering to make sure the universal application, it brings lots of troubles in choosing element, in defining the beam material characteristic and in setting the elasticity support in analyzing the CABM. Being the important large-space structure designing and analyzing software, although MSTCAD has professional function of structure designing and static force calculating, it still remains great blanks in dynamic analyzing. In this article, dynamic program for CABM is designed by VC++ language, and integrated into MSTCAD. The dynamic characteristic of umbrella-shaped cable-membrane structure is systematically research.This article traced back to the developed history and research condition of CASM, and introduced the Object-Oriented Programming method and Finite Element Method.The article deduced the basic dynamic equation of elastic structure and listed lumped mass matrix and consistent mass matrix for the CASM. It also defined and classified the damping matrix and introduced the problems of structural natural frequency and dynamic response.The calculate method of generalized eigenvalue is simply introduced and it analyses the problems which is encountered in traditional method of subspace iteration method in calculating the CSBM. Compared by dynamic program, it was proved the better calculating efficiency and better stability of the new method in calculating large structures.Lanczos method is optimized in LDLT triangular decomposition , vector reorthogonalization and result judgement. At the same time a new method of result judgement is brought forward, and named mode compare method. The example proves the optimized results of the method.Based on Lanczos method, the CSBM program is designed. According to comparing with ANSYS by analyzing results of several project cases, good efficiency and high precision of the program which is discussed in the article is shown.With deducing the mode decomposition response spectrum method, its several deficiencies in calculating CSBM is pointed out. As a new method for seismic response, the revised mode decomposition response spectrum method is proposed. Furthermore the response combination method of spectrum is discussed.The natural frequency and vibration of the CSBM is analyzed, and the article did different researches in the effect on the structure frequency by three main parameters, such as stress ratio of cable-membrane, membrane stress, rise-span ratio and so on, in separately. By large amount of theory numerical value, a fitting equation of the first frequency for the CSBM is given and proved by calculated model.