Parametric Design And Static And Dynamic Analysis Of Open Ellipsoidal Lattice Shell

With the continuous progress of economy and technology,people’s sports and recreational activities become more and more rich and demands for large-span spatial structures are soaring.Open ellipsoid spatial structures by combining structural characteristics of both rod system and shells are widely applied in large stadiums and entertainment architectures.Open ellipsoid lattice shell structure improves the phenomenon of stress concentration caused by too many rods concentrated in the vertex in traditional ellipsoid lattice shells so as to make the grid distribution no longer limited by the size of nods on the top of the lattice shell and make forces more reasonably distributed on the structure and it has such advantages as beautiful shapes and curves,geometries with strong adaptability to various fields and good lightning which is deeply adored by designers.This thesis uses ANSYS software’s APDL(ANSYS Parametric Design Language)to parameterize design languages and it develops parameterized design models and force analysis procedures for six kinds of open ellipsoid lattice shells and studies the static and dynamic performance and structural optimization design of the six kinds of open ellipsoid lattice shells.The main works include:(1).This article introduces in detail the parametric design ideas and methods of the open ellipsoidal lattice shell.It introduces vector height partition coefficient p and transforms the ellipsoid’s standard equation into parameter equation which is convenient for programming and then it uses APDL to parameterize design languages and establishes parameterized design macroprogram for six kinds of open ellipsoid lattice shells.(2).According to the characteristics of the six kinds of open ellipsoid lattice shells,it uses the formula for distance between two points in space to deduce the geometry parameter expression of rods of the length of any length on the open ellipsoid lattice,obtains quantitative relations of the lattice shell’s related parameters based on the expression and then optimizes the grids.According to elliptic area formula,it deduces area expressions of the opening part which lays theoretical basis for model optimization in the next step.(3).It uses ANSYS software to analyze the static performance of the six kinds of open lattice shells,studies the influence of different length span,rise-span ratios and other related parameters on static performance and summarizes a series of conclusions with practical engineering values.According to the conclusion based on static analysis,it uses the opening part’s expression to improve and optimize models and summarizes an optimization method about dressing vector height partition coefficient and the optimized model after analysis has better performance under stress.(4).Introducing the price conversion coefficient q,and innovating the theoretical model of shape optimization design of the reticulated shell structure,transforming the problem of solving the total cost of the structure into solving the problem of the total quality of the structure.The optimization model and the original model were designed for shape optimization,and some conclusions with engineering reference value were drawn,and the optimization model was still economically superior.(5).The dynamic performance of several open reticulated shell structures and their corresponding optimization models are analyzed.The natural vibration characteristics of these reticulated shells are summarized by modal analysis,and the seismic response of the structures is analyzed by time-history analysis method.At last,it summarizes and prospects to the bright future of open ellipsoid lattice shells.