Research on impact resistance of new suspended elastic safety net system

Abstract

In order to reduce the direct injuries caused by falling from height, we propose a new type of suspended elastic safety net system suitable for pylon assembly construction. Analyze the correlation between damping and toughness of the protection system, establish the falling object motion control method, and construct the mechanism model of the protection system accordingly. Full-scale impact tests are carried out using test pylons on transmission line projects. Test data is collected using high-speed cameras and dynamic data acquisition equipment to analyze the key impact dynamic response characteristics of the test model. The experimental results show that the system has three working stages. In the first stage, the elastic safety net is transformed from an initial equilibrium state, where it is subjected only to its gravity, to a taut state. In the second stage, as the elongation of the system continues to increase in the direction of impact, the internal forces transmitted by the net to the elastic rod and the supporting rope gradually increase until the energy dissipating devices connected to the elastic rod are activated. In the third stage, additional elongation of the system is provided by activating the support springs in the bearing supports. Based on the failure modes observed in the tests, the key factors leading to the breakdown of the system are investigated. A new numerical simulation method is developed which is not only capable of predicting the load-bearing capacity of an elastic safety net system under the impact of a falling object, but also accurately simulates the main operating characteristics, such as buckling of the elastic rods, activation of the energy-absorbing devices, and deformation of the net ropes. The numerical simulation model was evaluated using the experimental results, and the numerical response of the system was in good agreement with the experimental data.