Design of laminated composite structures is a complex process that requires the use of efficient modelling and optimisation tools. This thesis presents a finite element formulation with the option to include draping in structural analysis and optimisation.
The element is a 4-node shell element stabilised with enhanced assumed strains and mixed interpolation of tensorial components. The element is formulated to account for non-linearities from large displacements and stress stiffening with a novel penalty method presented for inclusion of the drilling degree of freedom. Discrete material optimisation is used for fibre angle optimisation with draped fibre angles from a decoupled draping analysis included through the rotation of the constitutive matrix.
Improved accuracy was achieved in linear tests and improved convergence in geometrically non-linear tests with independence from the drilling penalty observed in almost all cases.
Both inclusion of draping and use of discrete material optimisation was successful and yielded different optimal designs in linear compliance optimisation with draping.
The 4-node shell element is proved efficient, robust and accurate in analysis and optimisation of laminated composites.
Including draping in linear compliance optimisation only showed little gain but more is possible in complex problems and for other optimisation objectives, such as strength.