Research On Key Technologies In Part Variant Design With Structure Transplantation And Its Applications

This dissertation takes the part structural variant design as the investigative object, and a method for part variant design with structure transplantation is proposed. Based on the part variable model, subdivision and reorganization of part unit structure, as well as the methods of mapping topology faying and bridging topology faying for structure transplantation are studied. Furthermore, a system for part variant design with structure transplantation is developed based on the new method, which is testified in the design of numerical control machines and other complex products.The main work of this dissertation is as follows:In chapter 1, the relationship of part variant design and product variant design is analyzed. An overview of product variant design and part variant design is provided. Along with the analysis of related theories and technologies, the research background, the main content and the meaning of this dissertation are stated.In chapter 2, the construction of part variable design model is the basis of part variant design with structure transplantation. According to the need of part variant design, by merging the functional, geometric and semantic information of part and part unit structure, part variable design model is defined. And the association of each part unit structure and the regeneration method for part variable model are elaborated.In chapter 3, the subdivision and reorganization methods for part unit structure are discussed. First, three basic types of part variant unit structure are classified as: independent type, included type and combined type. Then, based on the needs for the determination of part variant unit structure, virtual cutting based subdivision method and information merge based structure reorganization method for part unit structure are proposed. With the combination of subdivision and reorganization method, many more part variant unit structures of various grades can be determined, and the application of part variant design with structure transplantation is greatly expensed.In chapter 4, topology faying method is the key technology in part variant design with structure transplantation. Firstly, the concept of topology faying surface is defined, and based on the types of topology faying surface, the topology faying of structure transplantation is divided into two types:regular surface faying (overlapped faying, plane faying, cylinder faying, plane-regular surface faying) and free-form surface faying. For regular surface faying, the mapping topology faying design is proposed, including translated transform mapping faying, rotated transform mapping faying, blend mapping faying and coordinated mapping motion for the variant design process.In chapter 5, to solve the problem of free-form surface topology faying, the bridging topology faying method is proposed. First, transplantation structure is pre-processed, faying problem is technically transformed, and with the introduction of Hermite interpolation curve method and 3-D promotion of design parameters, Hermite interpolation surface is obtained; then, with the materialization of the closed region formed by reference faying surface, target faying surface and connecting surface, the bridge of free surface topology faying is acquired, thus the topology faying of free surface is realized.In chapter 6, a system for part variant design with structure transplantation is developed. The prototype system is applied in the design of some typical parts of numerical control machine and other complex products, which shows the validity and feasibility of the new theory and method proposed in this dissertation.In chapter 7, conclusions are given along with recommendations for the future research.