Research On Function Acquisition And Redesign Of Adaptable-function Mechanical Product

The adaptable-function mechanical product can deliver multiple functions by adjusting or replacing some of its structural components.They take certain percentage of market share because of some specific strengths,such as being of compact structure,one product for multiple purposes,easy to upgrade and expand,and so on.Current research on this kind of product is relatively scarce.To address this problem,this thesis carried out research from three aspects.Firstly,by studying the characteristics of the adaptable-function mechanical product,it proposed a method to acquire the adaptable functions on the base of the information of function and behavior.Secondly,by applying the C-K(Concept-Knowledge)and FBS(Function-Behavior-Structure)theory comprehensively,it proposed a redesign process method that integrates FBS theory and C-K theory.Finally,by employing the FTA(Fault Tree Analysis)method,it analyzed the reliability and the weak links of the adaptable-function products.The details follow.Firstly,by representing function through the energy flow,material flow and information flow,the thesis conducted research on function acquisition.According to the characteristics of the adaptable-function machine,it proposed the principles for function selection,with which the designers can select the appropriate function quickly and carry on the next step of design.The obtained functions are classified and stored in the database,and a software platform was developed,which can be used to query and select functions to help the designers carry out the design process efficiently.The effectiveness of the proposed methods was verified by the adaptable-function design process of a mini electric jade grinder.Secondly,the thesis carried out the research on adaptable function redesign through the energy flow and executing behavior.By analyzing various mechanical products,it proposed a redesign process method that integrates FBS theory and C-K theory,whereby different functions were achieved with same behavior and different executing structures,and the C-K theory was employed to guide the FBS mapping process,from which different structures were combined to implement the required adaptable functions for the mechanical product.Based on this method,a software prototype was developed to assist the design process.In the end,a case study of redesigning a fixed-function power drill to being an adaptable-function one was presented to demonstrate the feasibility of the proposed methodology.The research provides certain guidance to designers in redesigning this kind or similar kinds of products for functional adaptability.Finally,based on the analysis of adaptable-function mechanical product,the thesis analyzed the reliability and the weak links of the adaptable-function products by introducing the FTA method.It can not only guide the designer to optimize the design in advance for weak links,but also assist the maintainers to carry out their work.The effectiveness of the proposed method was verified by the small multi-function cutting machine.It can find the parts that are easy to failure,and analyze the reliability of the product and the probability of occurrence of the top event.The proposed methodology can also be used to support the designers to optimize the design and evaluate the designed products.