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In order to understand the quasi-static and dynamic compressive mechanical properties of carbon/epoxy composite laminates consisting of unidirectional carbon fiber plies and carbon fabric plies, several quasi-static and dynamic compression experiments were performed along three principal material axes. Dynamic compress experiments were conducted using the compression split Hopkinson’s pressure bar (SHPB) and MTS machine respectively. The experimental results showed that the materials had obvious strain rate effect. The performance of the composites in each of the three principal directions had unique characteristics. In the vertical direction of the carbon cloth, the materials had an obvious linear constitutive relationship. In-plane along the 0° carbon fiber direction, the carbon fiber controlled the mechanical properties and the strain rate effect. Specimens were also equipped with various failure modes. Failures were due to shear fractures in the normal direction and due to delamination and splitting failures in the in-plane direction. Identical tests were conducted for the unidirectional laminate. The results show that the static compressive strength and the dynamic peak stress values of fabric laminates were higher than those of unidirectional laminates under the same conditions.

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A dynamic crystal plasticity model for a low-symmetric β-cyclotetramethylene-tetranitramine single crystal with only limited operative slip systems has been developed, accounting for nonlinear elasticity, volumetric coupling with deviatoric behavior and thermo-dynamical consistence. Based on the decomposition of the stress tensor, a modified equation of state for anisotropic materials is employed. Simulations of the planar impact on the β-cyclotetramethylene-tetranitramine single crystal show good agreement with existing particle velocity data in the case of (110) and (011). Pressure snapshots, the dislocation density, the shear stress and the strain localization for β-cyclotetramethylene-tetranitramine single crystal under shocked loading are discussed. The present model provides more insights into a range of complex, orientation-dependent elastic and inelastic behaviors in shocked explosive crystals than isotropic elastic–plastic constitutive descriptions. The proposed formulation and algorithms can also be applied to study other low-symmetric crystals under high-pressure shocked loading that deform mainly by crystallographic slip.

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