Explicit Finite Element Simulation of Ship–Structure Collision Using LS‑DYNA 

Offshore structures such as wind turbines are increasingly exposed to accidental ship impacts as maritime traffic and offshore wind capacity continue to grow. These collision scenarios involve extreme loading conditions over very short time scales and can lead to severe local damage as well as global structural consequences. Engineers are therefore required to assess not only the initial impact but also the subsequent structural response and potential cascading failures. 

Engineering Challenges

Ship–structure collision events are governed by strong geometric, material, and contact nonlinearities. Large plastic deformations, local buckling, and folding of steel components occur within fractions of a second, while multiple transient contact interfaces form and disappear throughout the event. Conventional implicit finite element methods often struggle with convergence under these conditions, particularly when high strain rates and rapidly changing contact states are involved. 

In addition, realistic collision analyses require large-scale finite element models to capture local damage mechanisms and global structural response. Practical engineering constraints on computation time further complicate the problem, forcing engineers to balance accuracy and efficiency. Beyond the initial impact, secondary effects such as global instability, collapse of support structures, or falling components may dominate overall risk and must be considered at system level. 

An example: Offshore wind turbine collision

An offshore wind turbine supported by a monopile foundation was analyzed under accidental ship collision scenarios. Several representative vessel types were considered to reflect realistic offshore traffic, including large cargo and passenger vessels with varying mass, hull geometry, and structural stiffness. Both sailing and drifting impact conditions were investigated to capture a wide range of possible collision events. 

The wind turbine model included a tall steel tower, monopile foundation, and a heavy nacelle. A fine mesh was applied in impact zones to capture local deformation, while coarser representations were used elsewhere to control model size. Soil–structure interaction was included to represent load transfer into the seabed and its influence on global response. 

Results and Insights

The simulations showed significant plastic deformation in both the vessel and the offshore structure, with impact energy primarily dissipated through hull crushing and bending of the monopile and tower. Damage patterns and structural response were strongly influenced by vessel type, impact velocity, and location of impact. 

In high-energy scenarios, global instability of the support structure was observed, potentially leading to collapse toward the vessel. While the initial collision did not always result in catastrophic damage to the ship, secondary effects proved critical. In particular, the detachment and subsequent fall of the nacelle introduced a severe additional hazard, causing substantial damage to the vessel and highlighting the importance of considering consequential damage mechanisms. 

Why use LS-DYNA?

LS‑DYNA addresses these challenges through explicit time integration, which is particularly well suited for short-duration, highly nonlinear events such as ship collisions. By avoiding global equilibrium iterations, the explicit approach remains stable in the presence of large deformations, complex contact conditions, and severe material nonlinearity. 

The tool provides advanced material models capable of representing elastic–plastic behavior, strain-rate effects, and energy dissipation mechanisms that are critical for impact simulations. Robust contact algorithms and flexible discretization options, including shell and beam elements, allow engineers to construct efficient yet physically realistic models. This makes LS‑DYNA a preferred tool for collision and impact analysis in offshore applications. 

Conclusions

Ship–structure collision analysis in offshore environments presents extreme numerical and physical challenges that are difficult to address using conventional implicit methods. Explicit finite element analysis with LS‑DYNA provides a more robust and efficient framework for capturing impact response, progressive damage, and system-level consequences. 

The presented example demonstrates how LS‑DYNA enables engineers to move beyond local damage assessment and evaluate cascading failure mechanisms that are essential for realistic risk assessment and informed offshore design decisions.