Shape-State Optimization Of Tensional Membrane Structure

Tensional membrane structure is a kind of novel space structure,which carries load within membrane material and cables.As a flexible structure,the design of tensional membrane structure is different from traditional structures for its requirement of initial shape-state analysis.Shape is the profile of the structure and state is the distribution of the stress.The shape and the state have one-to-one correspondence with each other under given boundary conditions.The initial shape-state is crucial to the beauty and the mechanical characteristics of tensional membrane structure.So,how to optimize it in conjunction with engineering applications is a hot topic of recent researches.In this dissertation,shape-state optimization is studied on the basis of summarizing researches both at home and abroad.First of all,the method of the form-finding based on ANSYS is improved through the introduction of the new thermal stress calculation formula and the new way of cable stress application.By the means of this,the problems of being unable to take the possion's ratio into account and the great deviation of the cable stress are solved.Next,a previous established multi-objective model for shape-state optimization is improved.The constraints for stress and displacement of the structure are introduced to establish a new modified model.Then,based on the maximum entropy approach,a new algorithm is presented.This algorithm has been realized by integrating DOT and ANSYS. Numerical results show that the proposed method is valid and has some advantages such as absence of the weighting coefficient and fewer iteration numbers.Finally,the coupled and the decoupled method of tensional membrane structure are introduced and an example is present to compare the two different methods.On the basis of this,the coupled method is introduced to the shape-state optimization and a whole new method is formed.To prove the advantages of the new method,the differences between the shape-state optimization method based on the coupled and the decoupled method is presented through an example.