Quantification of Error Associated with Using Misaligned Meshes in Continuum Damage Mechanics Material Models for Matrix Crack Growth Predictions in Composites

摘要

The ability of a material model to capture in-plane matrix mode Ⅰ and mode Ⅱ crackgrowth is an essential component for modeling ply level damage evolution incomposite structures. Previous studies using a continuum damage mechanics (CDM)approach have shown success in satisfying benchmark solutions for mode Ⅰ and Ⅱcrack growth. However, success was shown using a fiber-aligned meshing strategy,which encourages matrix cracks to propagate in a single band of elements, along thefiber direction. Generating a fiber-aligned mesh becomes a highly involved processfor laminates including off-axis (non 0° or 90°) plies. The objective of this study isto quantify the effect of non-fiber aligned mesh discretization on predictions of inplanematrix crack propagation. The approach taken incrementally varies the meshorientation angle relative to the fiber orientation; more specifically, misalignedmeshes are used to quantify the effect of element angle orientation relative to theinitial crack orientation on the energy released during matrix crack propagationsimulations using a CDM method. CDM solutions obtained with the misalignedmeshes are evaluated against known benchmarks for mode Ⅰ and II matrix crackgrowth. The CDM solutions reveal a near-polynomial trend of increased predictedfailure stress with increased mesh misalignment angle; hence implying a potentialrelationship between element orientation angle and apparent fracture toughness.