| With the increasingly prominent environmental problems in China,the environmental awareness of the public is increasing and the related environmental laws and regulations are becoming more stringent,and the environment-friendly oriented design and manufacturing has become a topic of common concern.Green product development capability will be one of the key competitiveness for manufacturing enterprises in the future.The key of green product developing depends on the green design since product performance is largely determined by design.Developing a green design requires that environmental impact of the product should be considered throughout the design process and product’s environmental friendliness should be set as design objective.Life cycle assessment(LCA)is the most mature and widely used environmental impact assessment tool.LCA solves quantitative analysis problem of life cycle environmental performance,which can provide guidance for design decision and improvement direction.Therefore,LCA is considered as a potential green design aids.However,the implementation of LCA often takes a lot of time and resources,and have a professional requirement for executor.So,with the constraint of data,time and economic and knowlege,it is difficult to use LCA in the product design stage,and effectively play the guiding role in the green design.Therefore,this study proposes a key design problem of green design firstly: how to collect the life cycle data and establish an information transform mechanism from product design to LCA based on the existing design information and environment,to conveniently and efficiently carry out environmental performance evaluation.Aiming at this problem,this paper proposes a feature-based LCA-CAD(Computer Aided Design)integration approach.The information exchange mechanism between CAD(Product Design)and LCA(Environment Assessment)is mainly studied,and LCA-CAD integrated system architecture solutions is proposed.The main research contents include:Firstly,the definition and classification of life cycle-oriented features are proposed.In order to realize the information transformation between product design and life cycle assessment,this study analyzes the difference and correlation of modeling principle and information structure between CAD and LCA firstly.Then introduces the concept of feature as the carrier of information in different engineering fields.Product Features and Operation Features are presented as an expression and organization tool for product design information and life cycle information.Secondly,a feature-based lifecycle integrated modeling method is proposed.The product life cycle multi-view modeling method of "design oriented","process oriented" and "environment oriented",and the view transformation mechanism based on product-process-input-output feature mapping are established.The information extraction of CAD model and the method of product feature reconstruction are proposed.A mapping algorithm of product feature to process feature based on rule-based reasoning is proposed.Then,the LCA-CAD integrated system architecture and development scheme are proposed.The NX system is used as the CAD system.Feature extraction and reconstruction function is developed by NXOpen.The feature model based on parameterization and standardization is proposed.The LCA system framework,key function and development scheme are proposed.A database for typical machining feature’s parameters and mapping algorithm for machining products-process feature is developed.Finally,a case study on the step shaft is carried out,and the steps of LCA implementation under the LCA-CAD system integration environment are demonstrated.The feasibility,scientificity and effectiveness of the proposed method and development tool are verified. |
