Research On Profiling And Optimization Of NURBS Curved Thin-walled Parts

Large thin-walled workpiece made of the composite material is widely used in the field of aerospace, medicine, automobile and others. However, the deformation problem in the process of machining has never been solved very well. To solve poor rigidity and weak intensity of the thin-walled workpiece, the view that multiple points position and support the workpiece is proposed in this article. What's more, the thin walled workpiece with free surface is the object of research and the layout of locating or supporting points is optimized. This article is to complete the following items mainly:Firstly, this article totally introduces the technical difficulties of large thin walled workpiece in machining and more development needs of the clamping. This article introduces the research situations to solve the deformation problem of thin-wall workpiece both at home and abroad. At the same time, this essay proposes research background and significance and clears the main research contents, major research plans and related technical requirements.Secondly, this article establishes the geometrical model of thin-walled parts and puts forward the theory of multipoint location for thin-walled parts with curving surface and designs vacuum fixture system of the curved thin-walled parts.Then this article analyses the main structures and discusses type selection calculation of main components. In order to measure the deformation of thin-walled workpiece because of the layout of locating points, the concept of equivalent stiffness of thin-walled parts is put forward. The equivalent stiffness of thin-walled parts is calculated under different conditions by ANSYS software. Furthermore, this article explores the relationship between deformation amount and cutting force.Thirdly, through combination strong calculating ability of finite element analysis and search efficiency of genetic algorithm, this method realizes an optimal layout of anchor points. The method overcomes some problems while using randomness method, experience method and uniform method. Through the analyze of the given sample, the situation that the number of locating or supporting units is the minimum and the layout of anchor points is optimal is found. Compared with uniform method, the optimization algorithm is better for searching anchor points.Finally, this article describes all the contents, summarizes the results and puts forward the future development trend of the thin-walled parts with curving surface while processing. This paper presents study on search algorithm of anchor points and the design of fixture system and hopes to promote the development of large thin-walled parts with curving surface while processing and assembling.