Incorporating point cloud failure criterion in an orthotropic visco-elastic-plastic material model

A new failure criterion is developed to improve modeling of orthotropic structural composites subjected to quasi-static and impact loadings. Rather than using an analytical expression to predict failure that traditionally has been employed, a point cloud failure surface is constructed in the stress/strain space using a multi-scale modeling scheme based on a combination of virtual and laboratory testing. At the microscale, the constituent components of the composite are used in modeling a representative volume element (RVE) that is subjected to multi-axial state of stress until the first failure in the RVE is detected. A volumetric homogenization scheme is used to obtain the corresponding meso-scale properties for use at the meso or structural scales. During finite element analysis, the point cloud data is queried to check if the current state of stress in the finite element is inside or outside the failure surface using k-nearest neighbor (k-NN) classification concept. The failure criterion is implemented in an explicit finite element program as a part of the failure sub-model. A representative unidirectional composite is used to illustrate the developed procedure for two structural systems using thin shell finite elements – stacked-ply tests involving tensile and compressive loading at quasi-static, room temperature conditions, and a flat panel that is subjected to impact loading. Numerical results compare favorably with experimentally obtained results showing improved predictions compared to existing failure models. The developed multi-scale point cloud concept shows promise and potentially the developed framework can be extended to support a variety of composite architectures.