This thesis presents the development and validation of a progressive collapse methodology for composite structures based on advanced nonlinear finite element analysis (FEA). The method is applied to parametric studies in order to investigate the influence of boundary conditions, material configurations and geometric imperfections on the response of individual structural members that form a composite ship hull. Effects on the analysis from the type and size of finite elements adopted in the FE discretisation scheme are also considered by conducting mesh refinement studies. In terms of material nonlinear behaviour, failure and progressive collapse of the composite section is performed at ply level. Alternative failure theories are compared for accuracy over a wide range of material, geometric and loading configurations. Good correlation between numerical and experimental results is identified from failure theories that accommodate interaction between failure modes and adopting an instantaneous degradation approach for the damaged properties. Failure of the bond region between plate and stiffener is also being considered in the analysis by adapting cohesive zones which also performs well against a variety of physical tests. Parametric studies are performed on square and long plates in compression for a wide range of slenderness ratios. Effects from the shape, size and location of geometric imperfections are also considered. As a result, a set of data is produced that can be used as an initial basis for design curves. This includes failure initiation and ultimate strength for the range of layup configurations under consideration. These studies are repeated for alternative boundary conditions in order to demonstrate their effect on the panel response. An application example for the ultimate longitudinal strength of a GRP hull girder is provided at the end from the progressive collapse analysis at a global level. This is compared against solutions from simplified methodologies that are based on simple beam theory and demonstrates the necessity for considering interaction effects between local and global panel deformations in the strength assessment of the hull girder.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:576656 |
| Date | January 2012 |
| Creators | Misirlis, Konstantinos |
| Publisher | University of Newcastle Upon Tyne |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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