Study on Coupled Vibration of Armored Cable System Based on Traditional Finite Element Method

This paper addresses ocean currents’ impact on the performance of underwater robots with armored cables. To achieve this, we present a dynamic model for a variable-length-robot system, utilizing kinetic energy and work to describe the interactions between physical quantities in the system. The Langrage function is employed to derive the Lagrange dynamics equation, and the finite element method is utilized to discretize the continuous system of the underwater armored cable. Furthermore, the constraints and boundary conditions are handled by using Lagrangian multipliers, thereby solving the resulting system. The Morison formula simulates the coupling force between the armored cable system and the surrounding environment. The resulting theoretical model is numerically solved, the vibration response of the armored cable of the underwater robot is analyzed, and the relationship between the inherent frequency of the system and the boundary disturbance is obtained. The paper provides a foundation method for studying the dynamic properties of the armored cable system.