Keywords

Offshore wind turbine, acausal modeling, structural dynamics, soil-structure interaction

Abstract

Offshore energy systems present significant challenges in support structure design due to their scale and the strong coupling between aerodynamic, hydrodynamic, and structural subsystems. These interactions make traditional sequential modeling approaches inefficient for design exploration. Acausal modeling frameworks address this limitation by enabling direct integration of coupled subsystems without reformulating governing equations, improving computational efficiency while preserving physical fidelity. This supports rapid exploration of large design spaces, accelerates iteration cycles, and shortens the path from concept to deployment.

This thesis develops and validates an acausal multibody elastodynamics model for offshore support structures. The framework includes structural flexibility to capture member-level deformations and internal load distributions. Soil–structure interaction is incorporated to represent seabed compliance, which significantly influences global dynamic response. In addition, hydrodynamic wave loading is modeled to reproduce realistic offshore environmental conditions.

Model accuracy is assessed through code-to-code verification against established offshore simulation tools. Results show strong agreement in both static and dynamic responses across a range of environmental loading cases. In particular, the framework accurately reproduces key structural dynamic properties, including eigenfrequencies, mode shapes, and internal force distributions.

The developed model is implemented as part of the Control-oriented Reconfigurable and Acausal Flexible Technologies Simulator (CRAFTS), a Modelica-based library under active development. By unifying structural flexibility, soil–structure interaction, and hydrodynamic loading within a single acausal framework, the proposed approach provides a modular and extensible tool for offshore structural design and analysis. This enables more efficient engineering workflows and supports faster, more reliable design decision-making for offshore energy applications.

Completion Date

2026

Semester

Spring

Committee Chair

Das, Tuhin

Degree

Master of Science in Mechanical Engineering (M.S.M.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Document Type

Dissertation/Thesis

Identifier

DP0053300

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