In this study, the dynamic response of a multiconnected floating solar panel system with a vertical pontoon were studied under various scenarios. First, a floating solar panel pontoon is modeled by combining nine single-unit vertical cylinders (arranged in parallel, horizontally and vertically, 3 m apart from each other). Each cylinder will be considered a rigid body, and they are connected to each other with a frame, so that they can oscillate together. Each floating solar panel pontoon was connected to a steel pipe, and a hinged connector was attached to the connecting point of each steel pipe, while it was fixed at each pontoon. In this study, as a floating solar panel system, a 10 × 10 system was adopted at a water depth of 50 m. Furthermore, a catenary mooring system with steel wire rope was installed to enhance its station-keeping capability. As an environmental load, wave excitation force, under normal operating and extreme conditions, was considered. To confirm the dynamic behavior of the system, a connector boundary condition sensitivity test was conducted under a 0° heading (west to east). It has been proven that an unexpected dynamic response along the sway, roll, and yaw directions is observed in the hinged connector case, due to the second generated moment caused by the movement of the facilities. Furthermore, judging from extreme simulation results, the larger the external environmental loading, the greater the dynamic response of the system, due to amplified wave excitation forces. Finally, under the multiple mooring line failure scenario, the dynamic response of the system is significantly amplified, due to the loss of mooring tension, except for the roll response.

This study proposes a rational method for modelling ballast in tracks based on the discrete element method (DEM) approach. To simulate a ballast consisting of a group of gravels, it is essential to use the discrete element method. The ballast comprises randomly arranged gravels of unspecified shapes, and requires multiple steps and a separate house code for implementing the ballast. In this study, a simplified ballast analysis model using the parallel bond method (PBM) is proposed and verified through comparison with design standards. Additionally, case studies are conducted to investigate the effect of particle size distribution and micromechanical parameters on the simulation results.