The overall objective of this study was to develop and validate a predictive modelling methodology for simulating the static and dynamic impact failure response of thermoplastic composite sandwich structures. The work has primarily focused on sandwich constructions with commingled woven fabric glass/polypropylene composite skins and a crushable polypropylene foam core. The static and high strain rate mechanical properties of the thermoplastic composite skin material have been experimentally characterised. This investigation showed that the tensile and compressive modulus and strength increased with strain rate while the shear modulus and strength decreased as strain rate increased. A modelling methodology was developed for predicting damage in the thermoplastic composite using the advanced MAT 162 material model that is implemented in the LS-DYNA explicit finite element code. An inverse modelling technique for calibrating and validating the MAT 162 damage parameters was developed. The material model was validated for predictive simulation of the static and crash response of a large scale complex shaped demonstrator thermoplastic composite automotive component. The static and dynamic mechanical properties of the thermoplastic foam core have been experimentally investigated and presented. This was followed by an experimental investigation and finite element modelling of the failure modes of the thermoplastic composite sandwich under static and dynamic localised indentation and bending loads. A fracture criteria was implemented in the model to simulate core shear fracture. The main contributions to knowledge from this doctoral study are: the static and dynamic characterisation of the mechanical properties and failure modes of the thermoplastic composite and the crushable thermoplastic foam material; development of a validated modelling methodology for predicting damage in thermoplastic composites; and development of a finite element modelling procedure for simulating the static and dynamic impact failure behaviour of thermoplastic composite sandwich structures.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:514583 |
| Date | January 2007 |
| Creators | Brown, Kevin Anthony |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/10494/ |
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