Research On Vulnerability Of Automobile Assembly Line Based On Multilayer Complex Network Theory

With the improvement of China’s automobile manufacturing level,the automobile industry has become a strategic and pillar industry of China’s national economy.In order to meet the huge market demand,automobile companies use assembly lines to complete the production of large-scale,standardized cars.Because of the complicated and open assembly process,automobile assembly lines are susceptible to adverse factors such as disasters,equipment failures,and out-of-stock materials.The strong correlation between production factors makes partial damage of the assembly line cause the entire production line to collapse,which has certain fragility.Therefore,it is one of the key issues for enterprises to find the root cause of the vulnerability of the assembly line,and then propose a method to reduce the vulnerability to make the production line run smoothly and efficiently.In this paper,the interior assembly line of the automobile assembly shop of Company W is taken as the research object,and a multi-layer complex network theoretical model of the assembly line is established according to the production data of field investigation.Based on the complex network theory,the vulnerability of the assembly line is analyzed.The main research work and results are as follows:（1）Aiming at the problem that the traditional modeling method does not consider connection resources such as fasteners and cannot reflect the heterogeneity of production factors,a multi-layer complex network model of assembly line is constructed.The model contains three layers of sub-network: connection resource layer,process logic layer and operation physical layer.（2）By comparing and analyzing the topology structure statistical characters of sub-network and multi-layer complex network models,the clustering feature of multilayer complex networks on the assembly line is verified.Aiming at the problem that a single evaluation index of node importance is limited,an evaluation method which integrates indegree centrality,outdegree centrality,closeness centrality,betweenness centrality was performed.（3）Aiming at the problem of less research on the vulnerability of assembly lines,a vulnerability evaluation method is built in order to explore the impact of heterogeneous nodes and edge failures on the overall network vulnerability.The model takes nodes and edges as failure elements,and adopts random failures and deliberate attacks as failure strategy which simulates the failures during the assembly process.Compared with the traditional single-layer complex network of the assembly line,the rationality of the multi-layer complex network on the assembly line is verified.（4）Taking the automobile assembly line as an example,a multi-layer complex network model of the automobile assembly line is constructed.By analyzing the impact of different nodes or edges on the vulnerability of the automobile assembly line,an optimization plan for the assembly line vulnerability is proposed from the aspects of topology,equipment management,and personnel management.The optimization plan provides a theoretical basis for improving the stability of assembly line operation.