Research On Design Change Propagation Path Optimization For Complex Products Based On Complex Network

Product design is a continuously changing process that progresses from customer requirements to a mature design.In the process of complex product development,design changes are unavoidable and determine as much as 70–80% of the final cost of a product.Moreover,product development cycle and product quality are greatly affected by change activities.Change propagation imposes negative impacts on product design time and cost,which in turn affects product lead time and price.Because of the non-uniqueness of the change propagation paths,it is important to find the optimal change propagation path with minimum impact before implementing the change.As for the problem of complex product design change propagation path optimization,this paper proposes an optimal propagation path search method based on directed and weighted complex networks.The main research contents are as follows.(1)Multi-objective path optimization for design change propagation based on nondominated sorting genetic algorithm.First,the complex products are divided as components or parts and the complex product directed and weighted network is constructed based on the change propagation dependency between the complex product components.The change propagation probability and change propagation impact of each change are evaluated from the change propagation database.Cost and time of each development unit are obtained from historical data.The change propagation risk,development time,and development cost are calculated by introducing change propagation probability and change propagation impact.The change propagation risk,development time and development cost are taken as three optimization objectives.The non-dominated sorting genetic algorithm is applied to search the optimal path of change propagation and the optimal Pareto solution set is obtained.Finally,the effectiveness of the proposed method is illustrated by an example.The method is compared with the traditional Breadth First Search algorithm.The results showed that the proposed method can solve the multi-objective optimization problem,while the Breadth First Search algorithm can only optimize single objective.The algorithm complexity of the proposed method is also greatly reduced.Therefore,the method proposed in this paper is more suitable for solving the problem of complex product design change propagation.(2)The optimal propagation path searching of multi-source design change based on ant colony algorithm.First,the complex product is divided as components or parts.Change dependencies between them are established to build a product network model.The importance of the connection between components is evaluated by the LinkRank algorithm.Through the data extraction from the historical data and the product change database,the probability of change propagation and the design time of each component are obtained.The properties of each component,i.e.absorber/carrier/multiplier,are determined by calculating the change propagation index.Then,the change propagation intensity is evaluated by change propagation index,component connection importance,design task execution time,and propagation probability.Change propagation intensity is defined as the edge of product network.Thus,the product directed and weighted network model is obtained.After evaluating the change absorption capacity of each component and the initial change impact of each initial change component,the ant colony algorithm is applied to solve the multisource design change propagation model so that the optimal change propagation path can be obtained.The effectiveness of this method is illustrated by an example and the superiority of the proposed method is verified after comparing with the single source change propagation method.The results showed that the proposed method can solve path coupling problem in the parallel propagation process and obtain the global optimal solution.Firstly,based on multi-objective non-dominated sorting genetic algorithm,this paper proposed a method to optimize the propagation problem of single source design change.Since multi-source changes often occur in reality,a method based on ant colony algorithm was proposed to optimize the path coupling problem of multi-source design change propagation.There is certain practical significance for the proposed method to optimize propagation path of complex product design changes.It solveed the problem of multiobjective optimization in the process of single design change propagation and the path coupling problem of multi-source design change propagation.The proposed method can effectively reduce the cost of design change,save change time and provide feasible solutions for decision makers quickly.The thesis includes thirty two figures,sixteen tables and one hundred and four references.