Shape Optimization Of Five Developed Cylinder Reticulated Shell

Reticulated shell structure is a space frame structure that is composed of along the curved shell arranged according to a certain rule, smaller in size and roughly the same grid, has the advantages of saving material, uniform and reasonable in force, stiffness, single bar, easy installation, is the most widely used spatial structure in the current structure. The reticulated shell structure widely used has a greater amount of steel, the optimized design on it can obtain obvious economic benefits.On the basic type of single layer cylinder reticulated shell foundation, the developed type cylinder reticulated shell structure was proposed in this paper, parametric modeling and static analysis was realized, on the basis the shape aptimization design was completed.First, based on the original cylinder shell, five developed cylinder reticulated shell structure was presented by transforming the rectangular grid diagonal distribution, the type and characteristics of five kinds of developed type structure was summarized. The corresponding macro program was organized using the parametric programming language APDL in ANSYS, parametric modeling of the developed type cylinder reticulated shell was realized. A large number of examples was Cited, these examples show that the parametric modeling method and procedure is simple, efficient and practical, providing a great convenience for the future work. The conditional formula on grid shape of an equilateral triangular cylinder reticulated shell is derived on the base of parametric modeling.Then add-in program was organized using APDL language, the static analysis on the original and developed cylinder reticulated shell was done in ANSYS, the displacement and stress was extracted, when the rise-to-span ratio is certain, the maximum displacement and stress variation with the span about the rod loaded was summed up according to the static analysis results, and then the static analysis results on the basic and expanded type after loading were compared and analyzed in the same model parameter, displacement constraints and loading conditions, the relationship was got that different bar arrangement of the original and developed cylinder reticulated shell effect the shell stress characteristics.Finally two level optimization algorithm with discrete variables was researched, about that the first class section optimization using the relative difference quotient algorithm and the second class shape optimization using complex method. Based on this optimization algorithm, shape optimization program of cylinder reticulated shell was organized using FORTRAN language, and the shape aptimization design on the original and developed cylinder reticulated shell was completed adjusting cycly between ANSYS and FORTRAN. Through selecting a total of 240 optimization example analysis that the span is from 30 meters to 80 meters and the ratio of rise to span from 1/7 to 1/3, the relationship was got that different bar arrangement of the original and developed cylinder reticulated shell effect the total steel consumption.