Flexural and interlaminar shear study of hybrid woven kenaf/recycled GFRP (rGFRP) composites subjected to bending load

Delamination known as the failure at the interface between different layers is one of critical failure mechanism for laminates composites. Hybrid laminate composites comprised of unique ply material and structure, unwanted interlaminar shear stresses may occur between ply laminate due to different material behavior and properties. The aim of this research is to study structural integrity effect of interleaf glass mat and recycled GFRP waste (rGFRP) in woven kenaf reinforcement polyester composite. The properties of composites on ILSS and flexural behavior subjected to bending load were measured by flexural and short beam test (SBT). Span length to thickness ratio varies for both tests are 16: 1 and 4: 1 for flexural test and SBT respectively. Compression molding method was selected for composite fabrication; the fiber weight percentage ratios are constant at 35% of all samples. Results revealed that the flexural stress and flexural shear measured by flexural test is comparable for kenaf and kenaf/glass composites however, kenaf/rGFRP shows significant improvement, increased in maximum flexural stress up to 47.5%. Interlaminar Shear Strength (ILSS) calculated from SBT shows comparable value for all samples with slightly increased about 10% for both hybrid composites. Failure analysis observed by Scanning Electron Microscopic (SEM) and Optical Microscope shows severe interlaminar shear failure occur on glass mat hybrid composites for both tests. From the results, it can be conclude that hybridization of glass mat and rGFRP particulate improved flexural and ILSS properties. It also can be concluded rGFRP is potential to replace glass fiber as reinforcement