The Concurrent Optimization Design Of Material Selection And Structural Topology Based On GSFP Method

In order to meet the requirement of modern war, the higher design requirements of aircraft structure is put forward, such as lightweight, multi-function, high life, low cost, etc. The conceptual design plays a decisive role in the performance of the aircraft structure. The main task of conceptual design stage includes two aspects, one is to determine the material and the second is to determine the geometry. Therefore, material selection and structure geometry design are two important approaches to obtain higher performance of the structure. The purpose of this thesis is to construct an optimization model of concurrent optimization design of material selection and structural topology based on GSFP Method and its solution method. For titanium alloy structure, we carried on concurrent optimization design of material selection and structural topology. According to the optimized results we present a new material configuration, and to evaluate its performance. The main works and conclusions are as follows:(1) The selection optimization design of continuum structure. In this section, the structural stiffness and strength were considered the design objective and structural mass, and cost were used as the constraints. The sensitivity formula is derived. Numerical examples were also presented and discussed in order to illustrate the effectiveness of this proposed approach. Different weigh coefficients, constraints, and number of candidate materials are discussed by the numerical example. The result shows that compared to the initial design, the performance of stiffness and strength is better while the mass and cost remained unchanged. Since an increased number of candidate materials entail a larger design space, a better solution can be obtained.(2) The continuum structure concurrent optimization design of material selection and structural topology. Based on the material selection optimization, the void solid was regarded as a very weak material as the candidate materials for material selection optimization design, to achieve concurrent optimization design of material selection and structural topology. Numerical example showed that the method was successful in generating nearly 0-1 topologies for concurrent structural topology and material selection design processes. In structural strength design, the maximum Mises stress in the optimization results significantly below the stiffness of structure design optimization results, so the strength of the structure is capable of removing the stress concentration in some extend and the traditional stiffness design can’t.(3) The innovation configuration design of main bearing titanium alloy. The design level of the main load-carrying structure can reflect the design of aircraft structure level in some extent. Based on the background of aircraft titanium alloy structure design, we concurrent optimization design of material selection and structural topology. According to the result of the concurrent optimization, innovation configuration is put forward, and evaluates its structural performance. Results show that in the material selection design, compared to the high strength titanium alloy initial design, the cost of new scheme lower while fatigue life is almost the same; in the concurrent optimization design, as compared to the initial design, the new scheme can significantly reduce the structure weight, cost and maximum Mises stress, while the expense stiffness is smaller, thus, the goal of lightweight, low-cost and long-lived will be achieved.