Impact and damage behaviour of FRP-metal hybrid laminates made by the reinforcement of glass fibers on 22MnB5 metal surface

Hot stamping of 22MnB5 steel is know to yield very high strength of up to 1500 MPa depending on the final microstructure. In this work, different microstructures of 22MnB5 steel were produced by quenching with different cooling rates and then utilized to develop Fiber Reinforced Plastic (FRP)-metal hybrid laminates. By developing FRP-metal hybrid laminates using these hot stamped steels, the superior mechanical of it can be transferred to FRP-metal hybrid laminates. Two different types of FRP-metal hybrid laminates were developed in the study, one by reinforcing thermoplastic based glass/PA-6 FRP on steel surface using press-forming technique and other by reinforcing thermoset based glass/epoxy FRP using vacuum assisted resin transfer moulding process. By developing the FRP-metal hybrid laminates, optimal exploitation of the lightweight and high strength potential can be achieved. Both thermoplastic and thermoset based FRP-metal hybrid laminates developed by using heat treatment steel has better flexural properties compared to steel without heat treatment. In overall the PA-6 has better adhesion towards steel surface compared to epoxy polymer. The developed unsymmetrical hybrid laminates will consist of one side steel and other side with FRP and the influence of the damage behaviour with respect to the impacted side were investigated. Different failure behaviours were identified with respect to the impacted side. 22 J impact on the metal side of thermoplastic based FRP-metal hybrid laminates, developed by the hot stamped steel, requires 127.88% higher load compared to FRP laminates and 33.32% higher load compared to commercially available 22MnB5 steel.