Thesis

Integrating robotic welding constraints into the structural optimisation of ship structures for enhanced automated production

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Awarding institution
  • University of Strathclyde
Date of award
  • 2026
Thesis identifier
  • T18186
Person Identifier (Local)
  • 202265204
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • The maritime industry faces significant challenges in automating the assembly of complex ship structures. While automated joining is successfully implemented in open-block stages using inverted welding gantries, automation is severely obstructed once structures are assembled into enclosed, closed-block configurations. The ship's double bottom represents a critical application of these confined environments, requiring robotic systems to navigate internally within tight compartments. Conventional structural optimisation historically prioritised weight minimisation, introducing complex, dense stiffener layouts that render closed geometries "manufacture-impenetrable" and kinematically inaccessible to industrial robots. To bridge this gap, this thesis proposes a novel framework that embeds robotic welding constraints directly into the early-stage structural design phase as active, multiobjective parameters. Executed through a five-phase methodology, this research first maps industrial gaps via a systematic review, establishing the baseline for "Design for Automation." Second, production simulation of the double-bottom structural geometry demonstrates that robotic welding achieves an estimated 3.85-fold speed increase and a 1:2.75 energy-to-labour cost ratio over manual methods. Third, a structural optimisation engine coupling a Multi-Objective Genetic Algorithm with Response Surface Methodology is formulated to concurrently minimise mass and weld lengths. Fourth, a high-fidelity Virtual Prototyping Framework isolates kinematic limits within a compressed 1.2-meter clearance, proving the Elevated (On-Stiffener) configuration as the only commercially viable architecture due to Axis 3 ceiling collision risks. Finally, the integrated framework was realised on a ship's double-bottom block considering robotic welding constraint, achieving an 18.15% reduction in structural mass while maintaining a constant stiffener count and expanding the vertical robotic working envelope to a collision-free 970 mm clearance. The scantlings strictly comply with IACS CSR and Lloyd's Register standards (174.05 MPa stress; 1.1306 buckling load multiplier) with an error margin below 0.5%. This research establishes a definitive roadmap for Robot-Informed Design, concurrently optimising structural efficiency and automated manufacturability to advance global shipbuilding productivity. Keywords: Robotic Welding, Multi-Objective Structural Optimisation; Ship Production; Ship Structure; Confined Space; Cost Efficiency.
Advisor / supervisor
  • Oterkus, Selda
  • Oterkus, Erkan
Resource Type
DOI

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