Three-dimensional fibre optimisation with computer aided internal optimisation

Big efforts have been made to optimise the behaviour and the properties of fibre reinforced materials. The fibre-matrix bonding, the influence of the fibre-matrix content and many other relations of several systems have been intensively investigated. Nevertheless, the arrangement of the fibres within a structure was a neglected subject of research. CAIO (computer aided internal optimisation) was developed to predict the optimal arrangement of fibres for given load and boundary conditions. The mechanism of the method has been adapted from biological structures. CAIO is based on the finite elements method (FEM). In a first step the force flow of a structure is calculated by using FEM. The CAIO routine changes orientation of orthotropic axes into the directions of force flow with respect to the FE-results. A following stress analysis leads to a reduced shear stress distribution. The optimum fibre arrangement is calculated by an automatically iterative process of alternating FE-run and CAIO calculation. The latest version of CAIO allows the calculation of the optimum fibre arrangement in three-dimensional shell structures as well as in three-dimensional volume structures.