As an important supporting component, metal rubber clamp often generates nonlinear force and brings complex dynamics to pipeline system. However, the nonlinear of metal rubber clamps in pipeline system has been rarely incorporated in the open research. Therefore, based on genetic algorithm and finite element method, a new nonlinear clamp model with four degrees of freedom is proposed by introducing identified nonlinear parameters. The nonlinear parameters are identified by genetic algorithm in which the objective function is the error between experiment and simulation, and the nonlinear clamp-pipeline model is verified by modal test and vibration response experiment under different boundary conditions. The results show the numerical results are basically consistent with the experimental results. Moreover, the effects of clamp nonlinear stiffness coefficient, nonlinear damping coefficient, and excitation amplitude on vibration response of pipeline system are analyzed. The developed model can consider the nonlinear effect of pipeline system, so as to predict the vibration response more accurately.

This paper presents a virtual ski training system based on changes in environmental elements of ski resort. The aim of the system is to allow skiers to ski training without going to a ski resort, increase tactical training in the face of different environments and help skiers improve their performance. The system uses VR technology to construct a realistic ski training scenario. 5G cloud platform transmissions are connected to the actual ski resorts to obtain real-time environmental elements data to import into the VR system in order to construct a dynamic model of the environment. The effectiveness of the system was verified through a combination of indoor and outdoor tests to analyse participants' skiing speed in both real and virtual scenarios. In conjunction with questionnaires completed by the participants, differences in the effectiveness of the participants' experience of the different dimensions of the system were analysed. The results show that this VR system is effective in simulating actual ski resorts and is an effective aid for skiers, especially less experienced ski students.