Title:	Advanced simulations for renewable energy and ship crashworthiness
DNr:	NAISS 2025/5-550
Project Type:	NAISS Medium Compute
Principal Investigator:	Jonas Ringsberg <jonas.ringsberg@chalmers.se>
Affiliation:	Chalmers tekniska högskola
Duration:	2025-09-26 – 2026-10-01
Classification:	20309 20301
Keywords:

Abstract

We will work with structural design and fatigue for ships and marine renewables. Focus will be on two different aspects: Ship design for vessels with Small Modular Reactors (SMRs); Fatigue assessment of floating offshore wind turbines; both motivated by the transition to fossil-free power generation. In Ship design, SMRs can help reduce CO2 emissions while allow longer operations. But also brings important safety challenges, especially regarding collisions or grounding scenarios. Accurately modeling these situations requires detailed simulations that utilize large computing power. This research focuses on the structural solution of SMR-powered ships to improve safety in the event of large-scale accidents. Improvements to the ship's strength will be tested using extremely heavy and high-fidelity simulations. Abaqus/Explicit will be used, with nonlinear geometry activated and nonlinear material characteristics such as plasticity, strain-rate sensitivity, fracture initiation, and propagation. Also, contact nonlinearity increases the complexity, especially when solid elements are introduced. All these settings are needed to capture realistic structural behavior under nonlinear conditions that represent the complexity of real-life collision scenarios. Different designs and impact locations will be evaluated to assess the holistic structural response. Perturbation analysis will be performed, which will explore a wide range of collision and grounding scenarios. Heavy simulations are necessary since detailed models can predict how ships will respond to various factors that guarantee the designs remain safe and reliable even under real-life extreme conditions. After that, the performance of a real ship with these modifications under collisions and groundings will be examined. Finally, the overall effect of these solutions on the ship's strength will be analyzed, which may require modeling larger models than before with different nonlinearities. In Marine renewables, the majority of work will be for a set of well-defined problems where advanced simulation methodologies are needed to advance understanding. In some cases complete turbines will be studied, where the system perspective—combined with high spatial and temporal fidelity—is essential to capture the load paths that govern fatigue. The first concerns global-to-local stress transfer under non-stationary combined wind–wave loading. Abaqus/Standard implicit dynamic analyses will be performed to obtain interface forces and nominal stresses in shell/beam global models; these histories will then drive resolved solid submodels at welded toes, flanges, and penetrations, with contact and elastoplasticity treated in Abaqus/Explicit. The second concerns long-term damage modelling and its numerical robustness. Canonical “building-block” sea states will be studied primarily using statistically consistent rainflow counting and code-conformant S–N aggregation over multiple seeds. A third one is related to the effect of low-frequency platform motions and array-scale inflow turbulence on long-term fatigue. For this, we want to study how surge, pitch, and mooring dynamics modulate stress ranges and rainflow spectra. The overall objectives are to develop guidelines for the choice of modelling approaches that yield stable damage estimates, and that provides clear criteria for ranking critical details and prioritising design or retrofit actions.