Energy conversion of NPR protective net under high-energy impacts

The rapid expansion of infrastructure and transportation networks in the mountainous regions of Southwest China imposes significant challenges in mitigating rockfall-related geological hazards, posing threats to human life and engineering safety. In recent years, the frequency and intensity of high-energy rockfall hazards have escalated. To address these challenges, the design and failure mechanisms of protective nets under extreme impact must be tested and explored; however, many commercially available materials are insufficient to meet these demands. This study investigates the performance of Negative-Poisson’s-Ratio (NPR) cables made of high-strength, high-ductility steel as a new material for protective nets under repeated impact experiments for ultra-high-energy rockfall protection in Sichuan Province, China. This study aims to understand the energy transformation characteristics of protective nets under ultra-high-energy impacts. The experiment uses high-speed cameras, infrared thermography, and dynamic axial force sensors to monitor the deformation process. A comprehensive analysis is conducted on the ability of the net to absorb and dissipate energy, focusing on material deformation, thermal effects, and internal energy. Building on this, a multi-degree-of-freedom system is modeled from the perspective of structural mechanics to describe the interaction between the impactor and the protective net. A physical equation for energy transformation under repeated impacts is derived, offering theoretical support and insights for optimizing protective net structures and their applications in extreme conditions.