The user innovation community does not consider the impact of incentive mechanism of enterprise on the knowledge sharing behavior of lead users. In order to solve the problem, a new knowledge sharing behavior incentive mechanism for lead users based on evolutionary game was proposed. Firstly, the enterprise and lead users were regarded as the main players of the evolutionary game, and the models under the conditions that the enterprise did not adopt incentive measures and the enterprise adopted incentive measures were constructed respectively. Then, to explore the dynamic evolution process and evolutionary stable strategy of the system, the local stability analysis was performed to the two models respectively. Finally, through the computer simulation, the evolution results of knowledge sharing under the two conditions were compared, and the influence factors and the best incentive strategy of the knowledge sharing behavior of lead users were analyzed. Experimental results show that, the enterprise taking incentive measures can effectively promote the knowledge sharing behavior of lead users, and when the incentive distribution coefficient is controlled within a certain range, the system will reach the best stable state; the optimal incentive distribution coefficient is determined by knowledge sharing cost, knowledge search cost and additional cost; the knowledge sharing cost, knowledge search cost and incentive distribution coefficient can significantly influence the level of knowledge sharing behavior of lead users.

In the process of traditional impact assessment of engineering change propagation for complex products,the joint effect of different association relationships among parts on change propagation is not comprehensively considered. Therefore,the multiplex network theory was applied to the modeling of complex product. Firstly,to explore the impact of different association relationships on engineering change propagation,the parts of a complex product and their functional, behavioral and structural association relationships were abstracted to a multiplex network. Then,the improved all-around distance index was used for evaluating the importance degrees of nodes in the multiplex network. Finally,the Susceptibility-Infection-Susceptibility(SIS)model was used to quantitatively assess the impact of engineering change propagation. To verify the effectiveness of the proposed method,the impact assessment of engineering change propagation of a type of diesel engine was taken as an example. Results demonstrate that:the multiplex network can fully describe complex products with different types of association relationships;the improved all-around distance index increases the ability to distinguish the importance degrees of nodes with the same coreness;the change in high-important parts will cause the avalanche propagation of engineering change throughout the product range.