Dynamic compression of carbon/epoxy quasi-isotropic in-plane 3D composites

Carbon/epoxy quasi-isotropic in-plane 3D composites and 3D orthogonal composites were made by non-woven manufacture technique for 3D fabric and resin transfer molding(RTM)process.The in-plane and through-thickness compression properties at different strain rates of carbon/epoxy quasi-isotropic in-plane 3D composites and 3D orthogonal composites were tested using SHIMADZU universal material testing machine and SHPB measurement system.The compression stress-strain relationships,failure modes under quasi-static and high strain rates were investigated.The results show that the compression performance of carbon/epoxy quasi-isotropic in-plane 3D composites is strain rate dependent in the directions of in-plane and through-thickness.The compression properties of the composites are more strain-rate sensitive than those of 3D orthogonal composites.Under quasi-static loading,the production and spread of shear bonds are restrained by ±45° fibers in quasi-isotropic in-plane 3D composites and the brittle failure mode is more uniform.With the increase of strain rate,the failure modes of the composites are shear in the in-plane direction and the fracture is more rough than 3D orthogonal composites,the failure modes of the two composites are the same in the through-thickness direction.