Evaluation of the Vanishing Fiber Diameter Model for Composite Plasticity

Abstract

The Vanishing Fiber Diameter (VFD) model for composite plasticity offers a computationally efficient approach to composite structural analysis and design problems. However this material model provides rather inaccurate predictions of composite deformation in a direction transverse to the fiber reinforcement. Empirical modification of the model is generally required to account for mesomechanical effects not present in the basic theory. Although systematic empirical modification of the VFD approach can provide accurate models of unidirectional composites, similarly accurate models of more complex laminates do not necessarily follow. The results suggest that laminate material models based on orthotropic lamina substructures do not in general provide a suitable basis for elastic-plastic structural design.