The nonlinear finite element modeling and performance analysis of the passive heave compensation system for the deep-sea tethered ROVs

Abstract

To improve the safety of the launch and recovery of the deep-sea remotely operated vehicle (ROV) under harsh sea states, the passive heave compensator is usually equipped. Through dynamic modeling and performance analysis of the compensation system, it can provide theoretical reference for the design and operation of the system. Firstly, the geometrically exact beam element was used to obtain the two-dimensional nonlinear finite element model of umbilical cable, and the continuous dynamics model of the compensator was built and discretized to one finite element, and then inserted as the first element of the whole model. The Newmark method was used to solve the total finite element model numerically. Finally, the performance of the passive heave compensation system under different effects such as the ship heave period, the stroke of the compensator, the working depth of ROV and the sea current speed were analyzed. The results show that the condition of smaller ship heave period, the longer stroke of heave compensator, under the critical depth and the less sea current speed will produce the better performance of passive heave compensation, and the performance for cable tension is better than that for cage heave motion.