Integrated Environmental Impact Evaluation Lightweight Design Method Of Plastic Pipe Extrusion Dies In Life Cycle

With the development of industrial, extrusion dies have been widely used for production and manufacture of plastic pipe. Extrusion dies are usually designed based on designers empirical. In order to ensure strength and stiffness, it tend to enlarge the size of extrusion dies. Due to lack of reasonable design method, these design methods have led to overweight and waste in material. Lightweight design is usually used to reduce weight and increase material efficient of products while ensure the mechanical performance of products. However, lightweight design method is not always led to reduction in raw material and resource from the whole life cycle perspective. The structural changing and material optimization in design stage of lightweight design may influence environment impact changing in other life cycle stage, even increase material and resource consumption of products. However, current lightweight design method only considers weight reduction as optimization objective, while ignore resource consumption and environment impact over its full life cycle. Therefore, in this paper, a lightweight design methodology oriented plastic pipe extrusion dies is proposed. This method integrating structural optimization and life cycle environmental impact evaluation is used to achieve weight reduction whist improving environmental performance in the life cycle of extrusion dies.Firstly, the structural feature of plastic pipe extrusion dies has been analysis and exist problem of current lightweight design and extrusion dies has been presented. According to these result, a framework of lightweight design methodology which integrating life cycle environmental evaluation is proposed. The proposed methodology based on structural optimization is considering mass and environmental impact in life cycle of extrusion dies as objective. The shape parameters of different components of extrusion dies are used as design variables, while the stress and displacement of extrusion dies for plastic pipe are used as constrain condition.Then, conducting deep research of selection of objective and constrain condition in structural optimization process. Fluid simulation based on Finite element analysis(FEM) and Fluid Mechanical is presented to obtain temperature and pressure distribution of fluid surface. And the structural thermal-mechanical coupled analysis is conducted to analysis temperature, stress and displacement condition of extrusion dies for plastic pipe. And the result would be sued as boundary condition of lightweight design. Environmental evaluation based on method and theory of Life Cycle Assessment(LCA) is used to obtain environmental impact condition of extrusion dies in life cycle. According to the evaluation result, the function relationship between environmental impact and shape parameters of extrusion dies is obtained, which will be sued as objective of lightweight design.Finally, based on the above research, selecting shape parameters of extrusion dies as shape variables of structural optimization. Combining with structural optimization method, establishing mathematic model of lightweight design. By applying the proposed methodology, the lightweight design extrusion dies are obtained. Comparing environmental impact of extrusion dies among original, traditional lightweight method and proposed lightweight design method of this paper. And verify the effectiveness and reasonable of proposed lightweight design approach.