Research Of Optimum Design Of The Space Truss On Basis Of The Discrete Variable

The space truss is one of the typical space structures. It is widely used in our country in recent years.The mechanics performance and mechanism of the space truss is analyzed in this paper. The static mechanics performance of the space truss is analyzed with method of finite element method. The dynamic response of the earthquake is analyzed with the method of the response spectrum method and time history method. And the results of the two methods is compared and analyzed. According to the compare of the two methods, it is reliable to analyze the earthquake response by the response spectrum method. And the response spectrum method is much safer than the time history method.The space truss is composite of discrete bars. According to the characteristic of the discrete variable structure, the optimization of the space truss is analyzed by the difference-quotient-method. Optimize the space truss under the loads of static and earthquake. The second moment method is used during the optimization course. That isthe first step deal with the partial variable restriction-stress restriction; and thesecond step deal with the integer variable restriction------displacement restriction.Because of the inefficient of the traditional difference-quotient-method, a new improved difference-quotient-method is advanced. And the efficiency of the optimization is increased.In the end of this paper, on the base of the large currency program------ANSYS,combine with the optimization method, the second exploitation of the optimization program is exulted. The program of the optimization is achieved. According to the optimization example of one space truss of a gymnasium, the efficiency and the feasibility of the difference-quotient-method is proved.