Multibody constrained dynamics of deepwater Y-method installation system

Installation of subsea equipment in deep water is a difficult task that necessitates a precise and safe executional strategy to minimize mishaps that might result in loss of life and equipment damage. Installation of a multibody structure is accompanied with undesirable dynamic behaviour and system responses. Due to its interconnec-tedness and nonlinearity, modelling the multibody dynamic system (MBDS) is challenging and complicated. In this study, the constrained dynamics of a multibody system is achieved by applying techniques including two tugboats and a payload in the context of an offshore installation scenario with a sea depth more than 1500 m. Given the lifting and installation operations performed using two wire ropes and three bodies with six degrees of freedom (6 -DOF), respectively, the coupled equations of motion of a multibody system are computed using Embedding Techniques or velocity Transformation Techniques. The hydrodynamic force and the two-strand forces are reduced to linear forces, but the hydrostatic force and the mooring forces are considered as nonlinear external loads. Runge-Kutta Method of Fourth-Order is used to calculate the numerical solution to the MBDS's equations of motion. The presented theoretical model is validated by comparing it to a previously published numerical model; the findings of both models are in good agreement. The outcomes of the suggested theoretical model are compared to the OrcaFlex numerical simulation. The suggested theoretical model dem-onstrates more computational accuracy and numerical stability than OrcaFlex. The findings of this investigation will enhance the safety and stability of multibody structure installation in deep water.