| With the rapid development of additive manufacturing technology and lightweight technology,lights parts are demanded in aerospace and automobiles with high standard,but the exiting lightweight methods are difficult to apply to the traditional manufacturing.Therefore,the combination of additive manufacturing technology and lightweight technology is a major trend.There are obvious advantages in this method,which can achieve lightweight design and manufacturing of structures through additive manufacturing.For structural lightweight design,there are many optimization methods,but structural topology optimization is one of the effective methods to realize lightweight design,the existing structural topology optimization still has numerical instability problems such as mesh-dependency and local minima,and the results of structural topology optimization cannot be directly used for additive manufacturing,so it is necessary to consider manufacturing constraints for redesign.The aim of this thesis is to study the lightweight method of continuum structure for additive manufacturing to improve “soft kill”bi-directional evolutionary structural optimization method.The improved method will be applied in the lightweight design of continuous structure--gooseneck hinge,then there will be a second design to the goose neck hinge in terms of manufacturing factors in additive manufacturing to verify the practicability and universality of the lightweight method.The main research contents of the thesis are as follows:(1)For the problem of slow iteration rate and numerical instability such as checkerboard,mesh-dependency and local minima in the existing structural topology optimization method.Based on bi-directional evolutionary structural optimization method(BESO)called "soft kill",studying improved single-constrained DBESO optimization method under volume constraints.The superiority and feasibility of the improved structural topology optimization method are verified by the topology optimization example of two-dimensional short cantilever beam and three-dimensional simply supported beam structure in MATLAB programming environment.(2)Based on the improved DBESO optimization method which is mentioned in part(1),considering the influence of displacement constraints on the performance of parts in the process of lightweight,displacement and volume constraints are settled and the improved multi-constrained DBESO optimization method are studied.In the MATLAB programming environment,the superiority and feasibility of the improved multi-constrained structural topology optimization method are verified by the topology optimization examples of two-dimensional Michell structure and three-dimensional bearing structure.(3)Because of complex parts structure in the the practical application,MATLAB can not be used to lightweight design of parts.ANSYS is applied to secondary development of improved structural topology optimization method by APDL(The development tools)to replace MATLAB,Which achieve lightweight design of complex parts.(4)Considering the manufacturing constraints of additive manufacturing,the gooseneck hinge is designed in lightweight design based on improved lightweight method and forming redesign with static simulation analysis.It is prove that the lightweight manufacturing method of the additive manufacturing structure studied in this paper is feasible. |
