Transient Dynamic Analysis and Vibration Reduction Optimization of a Marine ROV Launch and Recovery System Based on Viscoelastic Damping

The structural safety of a marine remotely operated vehicle (ROV) launch and recovery system (LARS) under extreme sea conditions determines the reliability of underwater exploration. To address the susceptibility of traditional rigid frames to local yielding and dynamic instability under transient high-frequency impacts from a mother ship, this study conducts structural dynamics simulation and vibration reduction optimization for a heavy-duty ROV LARS. A spatial finite element model was established, introducing boundary conditions that decouple the static gravity field from the transient inertial mass. Mechanical responses under eight typical operating conditions were systematically evaluated. Results indicate that the rigid frame experiences significant limitations under a 1 g horizontal transient impact, with peak stress reaching 195.38 MPa and deformation exceeding 20 mm. Consequently, a non-invasive vibration reduction strategy using viscoelastic damping boundaries is proposed, alongside an equivalent buffer dynamics model. Verifications demonstrate that this flexible damping constraint prolongs collision momentum transfer time and dissipates impact kinetic energy. Post-optimization, maximum transverse and longitudinal von Mises stresses decrease by over 37%, and transient deformation is reduced by over 64%. This study addresses the weight penalty of traditional strengthening designs, providing a mechanical reference for the lightweight design and impact protection of heavy-duty marine equipment.