Knowledge cooperation networks structure and evolutionary characteristics of international high-speed railway projects

Purpose This study aims to uncover the structure and evolutionary characteristics of the knowledge cooperation networks within international HSR projects from an industry chain perspective. It specifically examines the cooperative relationships among knowledge subjects, elements, and the interactions between them. The findings are expected to enhance the efficiency of knowledge cooperation in international HSR projects and provide valuable insights for future cooperate efforts. Design/methodology/approach This study adopts complex network theory, using the cooperative patent application data of international HSR projects from 2003 to 2023. The research period was divided into three stages. Initially, the study constructs two sub-networks: one for knowledge subjects and the other for knowledge elements. The structure and evolutionary characteristics are analyzed from industry chain perspective. Subsequently, establish a dual-layer knowledge cooperation network encompassing both subjects and elements. This paper further examines the discrete characteristics of knowledge subjects. Findings The research findings indicate that the knowledge cooperation sub-networks in international HSR projects have exhibited a three-stage expansion trend. The networks demonstrate small-world characteristics, suggesting a “clustering phenomenon” that results in low connection efficiency. Additionally, they exhibit scale-free properties and manifest a “Matthew effect”. Notably, some pivotal nodes serve as bridges that influence the direction and content of knowledge cooperation. Cross-domain cooperation also shows a positive developmental trend. In the dual-layer subject-element coupling network, knowledge subject diversity has increased, while the uniqueness has slightly declined. This indicates that cooperation in international HSR projects fosters the sharing of knowledge elements among different subjects. Practical implications The results contribute to clarifying the connections and evolutionary trend among nodes in the knowledge cooperation network, facilitating more effective improvements in the cooperation quality. They identify core subjects, and support these subjects in selecting partners and developing cooperative strategies. The analysis of key knowledge elements and the exploration of their cooperative directions help knowledge subjects to adjust resource allocation more strategically. These insights offer recommendations for achieving high-level international knowledge cooperation in HSR projects. Originality/value First, this study refines the analysis by adopting an industry chain perspective. This approach offers recommendations strengthening the efficiency of knowledge cooperation within and between the upstream, midstream, and downstream sectors of the international HSR projects. Second, this research explores the dynamic evolution characteristics, providing a deeper understanding of the development trends of knowledge cooperation. It is helpful for knowledge subjects to understand the development direction and key areas of knowledge elements, timely adjust cooperation strategies and seize market opportunities. Third, this study considers the decoupling characteristics of knowledge subjects and elements. Subjects can take different knowledge cooperation measures according to their level of knowledge dispersion characteristics. This provides a new perspective for analyzing cooperation networks in other complex engineering projects.