Modelling of anisotropic performance fabrics

In this paper, a model for predicting the stresses within a strained anisotropic fabric is presented. The fabric is characterised by tensile test data in the warp and weft directions as well as shear behaviour. The data is in the form of look-up tables that are capable of representing the non-linear form of each response. The model operates simultaneously on a triangular representation for both the 2D pattern defined on an undistorted fabric and an equivalent triangulation of a 3D representation of the fabric. An energy relaxation technique is applied to the situation in order to predict how the 3D representation should react in order to reach a minimum energy state. Arbitrary constraining configurations can be applied by setting a flag for each node to indicate those fixed in 3D. The resultant forces on fixed nodes can be determined. The model has been successfully applied to two examples. In the second of these, validation took the form of measuring the physical force effects of the fabric on an experimental rig and comparing them with those predicted by the model. It was then demonstrated that the model could predict other forces that could not be easily measured.