Key Technology Of Rapid Life Cycle Assessment Oriented To Conceptual Design

The rapid development of manufacturing promoted the rapid progress of human civilization, but also caused serious environmental burden. Increasingly serious environmental problems prompted the rapid development of green design and manufacture and sustainable development has become an important development strategy. Life cycle assessment (LCA) as a tool to quantify the environmental impact is a kind of key supporting technology for green design and manufacture, It is also an important basic theory for achieving manufacturing sustainable development. The conceptual design plays a decisive role in the life cycle of electromechanical products, so fully considering the whole life-cycle environmental impacts and developing green design during conceptual design phase can play a multiplier effect, which is currently hot point of academia field. However, due to the product design structures diversity and life-cycle information uncertainty, it is difficult to establish and quantify the relationship between conceptual design and life-cycle impact assessment, which has become the bottleneck problem in this research field. Based on the "Green Features" theory, a Rapid Life Cycle Assessment (RLCA) model for product conceptual design is proposed in this paper and these key technologies for RLCA of product conceptual design have been researched systematically.This paper proposes a product conceptual design modeling method based on structure configuration for solving the problems such as lacking design information, design information uncertainty during conceptual design stage, which lead it difficult to provide valid information for LCA. Firstly, according to the conceptual design process, the function and structure solving of product program is completed based on the functional requirements. Then, based on the "Fuzzy Similarity Theory", the similar function parts is chose out from the case library and constitute the approximate product solutions meeting the functional requirements. Consequently, product design information that LCA need is obtained.Based on preliminary studies of research group, the product program design information matrix is established for conceptual design phase to improve product program design information expression mechanism. Green Features Model is introduced to analysis the mapping relationship between design information and green information and clarify extracting and polymerizing process of green information.To solve the problem of design information on conceptual design phase with some uncertainty, the uncertain information in this article is divided into qualitative and quantitative uncertain information. The Intuition Fuzzy theory is used to quantify the qualitative uncertain information, and the Monte Carlo method is used to simulate and analyze the quantitative uncertain information combining with industry statistics. Consequently, the green information value and uncertainty factor are obtained to provide more accurate data for life cycle impact assessment.To solve the problem that conceptual design assessment methods lacks feedback mechanism leading it difficult to optimizing design, a sensitivity analysis model based on BP neural network is established in this paper. Firstly, a BP neural network with three layers is built and trained using product program green information and life-cycle impact assessment results as the neural network input and output parameters respectively. Then, the connection weights between input layer and hidden layer and the connection weights between hidden layer and output layer are extracted and analyzed to obtain the sensitivity relationship between green design information and LCA results. Thus, the design factors having greater impact on the environment are obtained to guide the optimization of the design.The purpose and function of RLCA software systems are determined combining with the RLCA process and method for conceptual design based on green design features. And the system framework is designed using C/S development model based on Visual Studio.NET integrated development platform. The RLCA software systems for product conceptual design is developed using C# and SQL Server technology.Finally, based on above theories and approaches, a blower system is taken as an example. The approximate product program is obtained through program function-structure solving and fuzzy similarity calculating. Then, extracting green information and LCA are completed. Finally, the optimization proposals are carried out after sensitivity analyzing by BP neural network.