Design Of Body Assembly Structure Optimization Module Based On Concept Design

The conceptual design phase can estimate and analyze the performance of the body structure, which is important to the confirmation of the body structure as well as avoiding the risks in the detailed design phase. In the conceptual design phase, we need to confirm the overall arrangement and assembly solution of the body, the merits of the solution will determine the final structure performance and process cost of the vehicle.This paper based on previous research work, considering the body manufacturing costs and assembly costs as well as the overall structure performance, using genetic algorithm, graph decomposition algorithm, breadth-first algorithm, NX/OPEN secondary development tools, basing on the VCD-ICAE system to develop and write an optimized module, and combining with Nastran solver to solve the structure performance and costs of the body to get the best optimal assembly solution.Firstly, this paper studies the background of the issues, the key technology of the system platform, the characteristic of the algorithm and language used, then develop the optimization module, the main work includes:the body assembly structure model is pre-divided and converted to the corresponding topology graph; then builds the corresponding data structure and segmentation vector of the topology link graph, and encoding for the topology link graph; using the operator operating of the genetic algorithm to divide the topology link graph into a single communication and not crossing sub-portfolio under engineering constraints; then taking the edges of the topology graph for target variables, the bearing stiffness of the body, the manufacturing costs, assembly costs for design target, using Nastran solver to solve and calculate the iteration to obtain the final optimal body assembly structure; and finally completes the design and development of the body assembly structure optimization module through the secondary development and the writing of the program.Pareto optimal criteria is used to screen the children results, so after the final iteration, there is no critical best individual but an optimal group, then through the comparison of the three individual target value and the consideration of practical engineering, we can get the relative best individual, which can indicate the effectiveness and reliability of the optimization methods and optimization module. This module realizes the optimization for the body stiffness, assemblability, manufacturability and gives the body assembly structure solution in the conceptual design phase, which is important for post-assembly and manufacturing.