A failure mode dependent continuum damage model for thick laminated composite plates

The fiber reinforced composite materials show stiffness degradation (termed as "Damage") upon loading, which can be modeled mathematically using Continuum Damage Mechanics (CDM). However, the available CDM models for composites are not characterized using all the uniaxial/shear stress-strain curves, therefore, do not account for the non-linear stress-strain behavior from all uniaxial/shear material characterization tests. Therefore, the novelty of this article involves the development of a failure mode-dependent phenomenological continuum damage model involving coupling of damage in different directions for generalized plane stress conditions and the characterization of model parameters based on experimental uniaxial fiber tensioncompression, matrix tension-compression, in-plane, and out-of-plane shear stress-strain curves. The finite element method with load, and displacement control is used to predict the evolution of damage in a moderately thick laminated composite plate subjected to quasi-static loading. The damage prediction capability of the developed model is compared with a failure mode independent damage model. The reported results depict the capability of the developed model to predict different damage in tension and compression in accordance with the strength values. The developed model is also tested using different coupling vectors (responsible for coupling of damage in different directions) to assess their accuracy in capturing the effect of coupling of damage in different directions.