ABSTRACT
Woven roving glass/epoxy and carbon/epoxy composites withstand higher impact loads owing to the presence of fibers in the direction. In the past, the effects of strain rate on different fiber orientations of unidirectional (UD) glass/epoxy and carbon/epoxy composites were investigated by several researchers. Most of these studies were performed under compressive loading using the split Hopkinson pressure bar (SHPB), but rate-dependent studies on different fiber orientations of plain weave composites under tensile loading using the drop mass setup are limited and have not been understood clearly. Therefore, tensile tests were carried out at different strain rates from 1.6 × 10−3 to 542 s–1 on different fiber orientations [(0/90), (0/90/30/-60), (0/90/45/-45) and (30/-60/60-30)] of woven roving mat glass/epoxy and carbon/epoxy composites and the (0/90) interply hybrid (glass/carbon/epoxy) composite. The displacement fields were captured in situ using the digital image correlation (DIC) technique and we post-processed the in situ data using the VIC-2D software to obtain the strain data. The Cowper-Symonds model was used to predict the strain rate sensitivity of composites. The strain rate effect was found to be more in all laminate configurations of glass/epoxy composite than those of the carbon/epoxy composite. For the same lay-up configurations of glass/epoxy and carbon/epoxy composites, the recorded tensile strength and modulus were higher and the failure strain was lower in the carbon/epoxy composite than those in the glass/epoxy composite. In both glass/epoxy and carbon/epoxy composites, the (0/90/45/-45) laminates have more strain rate sensitivity compared to the laminates of other orientations.
