Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties.

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Vancouver. His research interests are robotics, automation, fuzzy logic, technology assisted distance delivery of laboratory courses and haptic interfaces for virtual reality. Dr. Gurocak is an ABET Program Evaluator for mechanical engineering.

This paper aims to investigate the effectiveness of super-hard ceramic coatings by evaluating tool wear when drilling carbon fiber-reinforced plastics (CFRP) composite. The drilling experiments of CFRP are conducted with diamond-like carbon (DLC) coated, AlMgB14 (BAM) coated, AlCrN and Si3N4 and TiN (simply denoted as (AlCrSi/Ti)N) coated, and uncoated tungsten carbide drills. Each coating, dictated by its unique processing technique, provides unique thickness and morphology, and its physical properties, which makes the comparison among the coatings much difficult but enables to deduce the desirable attributes in the prospective coating ideally suited in drilling CFRP. To do so, after the drilling experiments, the tool wear was captured using the scanning electron and confocal laser scanning microscopes to construct the wear evolution that enables us to evaluate each coating qualitatively as well as quantitatively. Among the drills tested, the (AlCrSi/Ti)N-coated drills provided the best performance despite of the fact that (AlCrSi/Ti)N coating particularly are not harder than any other coating. The superior performance of the (AlCrSi/Ti)N coating can be explained by the comparable stiffness to the carbide substrate, 7.3 μm-thick coating consisting of the numerous nanoscale alternating layers between nanocomposite of AlCrN and Si3N4 and TiN coatings and the enhanced adhesion, which provide the effective cutting of carbon fibers. However, the thin DLC coating despite of its superior hardness and the BAM coating despite of its low friction did not perform at the level that the (AlCrSi/Ti)N coating was able to achieve.

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