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Bin Cheng,Dingjie Guan,Bingxue Jing 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.2
Small and medium-sized manufacturing enterprises involve a lot of customized products. The degree of adaptability should be noted while improving product design and manufacturing digital and intelligent levels. This paper presents a process sequencing method of manufacturing features based on the node importance of a complex network. The method is based on the adjacency matrix and connected graph to analyze the process constraint semantics of the product model. The adjacency matrix expresses the positioning dimensions between features. The connected graph is applied to define the constraint relationships between features and aggregate the multi-dimensional process dimension chain in all directions. Based on the processing sequence of node importance in a complex network, most of process planning can be realized. The method also can make adaptive decisions for different structural parts and monitor the machining of key features. Examples verify the validity and feasibility of the proposed method.
Shengpeng Zhan,Ruize Li,Tian Yang,Dan Jia,Jiesong Tu,Lixin Ma,Bingxue Cheng,Haitao Duan 한국고분자학회 2023 폴리머 Vol.47 No.3
The physical, chemical and mechanical properties of polymer materials used in water environment for a long time will change due to their water absorption characteristics, which will affect their tribological properties. This work studied the changes of physicochemical, mechanical, and tribological properties for five kinds of polymer materials (polyethylene, polyformaldehyde,polyamide, polytetrafluoroethylene, and poly-ether-etherketone) before and after water absorption. The mechanism of water absorption for polymer materials was revealed by molecular dynamics simulation. The results show that the higher the water absorption of polymer, the larger the swelling volume, the more the surface hardness and compressive strength decrease, and the toughness and friction coefficient of the material increase obviously. The water absorption status of polymer materials is closely related to the polarity of molecular chain. Water molecules are easy to form hydrogen bonds with polymer molecular chains of high polarity, which is the main factor of water absorption.