Optimization Of Cable-membrane Form-finding And Load-case Analysis Based On APDL Of ANSYS

As a new-type building structure, the cable-membrane structure has lots of merits such as rational mechanical performance, high efficiency, novel modeling and favorable economy, etc. and demonstrates the enormous vitality and wide application prospect. This paper has mainly studied theory and method of cable-membrane structure form-finding and load-case analysis. Parameter study is done with APDL of ANSYS.Firstly, the application and research situation on cable-membrane structure both at home and abroad is reviewed synoptically in this paper, and the definition and classification of cable-membrane structure system are definitely introduced. Basic assumption on cable-membrane structure analysis, non-linear finite element method, solution and convergence of non-linear equations are conceptually set forth.After having established the analysis model of cable-membrane structure and selected the type of element, taking the number of mesh, pretension value, time step and convergence tolerance as design variables of optimization, least area or weight of membrane as object function, maximum and minimum stresses and node displacements of membrane surface as state variables, the optimization of form-finding is done. As compared with professional software, the result of both is very close and calculation error is within engineering permission. The influence of deadweight and ratio of cable and membrane pretension on form-finding of cable-membrane structure is studied in this paper through several examples. The research conclusion is as follows: The change of surface curvature and deadweight in per-unit projected area larger, the influence of deadweight on form-finding larger. When holding the line pretension of cable and increasing pretension of membrane, structural curvature increases. Whereas holding the line pretension ratio of cable and membrane, the change of pretension value in cable or membrane does not affect structural form.This paper introduces how to determine wind and snow load. Taking form-finding optimized model as starting state of load-case analysis, this paper researches the influence of snow distribution coefficient, modules of elasticity, Poisson's ratio on the load analysis of cable-membrane structure, and obtains some conclusions: membrane surface curvature larger, influence of snow distribution coefficient larger; the increase of elasticity modules or Poisson's ratio can make maximum and minimum stress increase, as against, maximum vertical displacement decrease.Further, this paper studies difference between cooperative analysis and non-cooperative analysis of cable-membrane structure and obtains some conclusions: when considering cooperative model, tension stiffness will decline due to deformation of supporting structure; mechanical response rules of two computation models are similar, but stress of cooperative model shall decline little, and there is the bigger region on membrane surface where bigger displacement appears.Finally, based on sum up of research work of this paper, the further research of cable-membrane structure is looked forward.