Papers by Author: Dan Zhang

Abstract: A kind of model oriented assembly process simulation in WTK environment has been proposed. In the model, firstly, the assembly hierarchy of mechanical products can be presented clearly. Secondly, the assembly constraints between parts can be added to the model easily. At last, the assembly process information such as assembly sequence and path for each part can be recorded at real time in the model. Then, the converted method from PRO/E system to WTK environment about the mechanical product’s design information including geometric models, product design hierarchies and constraints has been discussed, which makes for easier building the model in the virtual environment.

Abstract: According to the characteristics of aerospace product, the model representation and storage of the rigid part and cable harness is proposed. The Dendritic Correlative Model of Mixed Assembly of Rigid and Flexible Parts (DCMMA-RFP) is introduced based on the hierarchical model and graph model. The assembly model which realizes the lightweight storage can clearly represent the hierarchy relation and assembly process of aerospace products. The assembly modeling process in the virtual assembly environment is detailed described. Finally the effectiveness of DCMMA-RFP is verified by an example.

Abstract: Aiming at the shortcomings of traditional assembly process design and immersive virtual assembly system, the architecture of Desktop Virtual Assembly System (DVAS) for interactive assembly process planning is presented. The key technologies such as data conversion and reconstruction of assembly models, assembly intention recognition and assembly control navigation are studied. The lightweight storage of assembly models’ data and the intelligent constraints recognition are realized. The problem of assembly operations resulted from the lack of immersion is solved by movement navigation. The algorithms were proposed and applied to the DVAS prototype, and an application case is studied to demonstrate the effectiveness of the system.

Abstract: The compound of micron powders and nanometer powders is a magnificent step in the application and development of metal matrix composite reinforced by nanometer particles. By taking nano-Al2O3 powders and Ni-based micron powders as the research object, the preparation process of metal matrix micro/nano-powders reinforced by nanometer particles with high energy ball-milling is discussed from three aspects: the additive process of nanometer powders, the additive content of nanometer powders, and the required ball-milling time in the paper. The results show that the additive process of nanometer powders which uses directly the dispersed uniformly nanometer suspensions as grinding medium can effectively decrease and avoid nanometer powders’ agglomeration of composite powders. Nanometer particles are well distributed in the composite powders. The optimum additive content of nanometer powders is consistent with the theoretical model of mixture ratio, which is determined by the ratio of the average diameter of micron powders and nanometer powders and their density of corresponding solid materials. Meanwhile, the required ball-milling time for preparation of better uniformity composite powders is no more than 0.5hr. This implies that the preparation process has a high productivity. Moreover, the preparation process is verified through other nanometer powders including nano-SiC powders and nano-CeO2 powders.