The use of fiber-reinforced polymer composites (FRPCs), due to their excellent mechanical and geometrical properties, namely high strength to weight ratio and ease of manufacturing, has gained a great deal of attention in many industries such as aerospace, defense, marine to name but a few. Currently, the most applicable FRPC laminates are fabricated with thermosetting (TS) organic resins, which exhibit great mechanical properties with a medium curing temperature range. Nonetheless, these TS-based laminates have the significant disadvantage of poor out-of-plane properties, as they exhibit brittle behavior that can increase the susceptibility of delamination, especially in impact applications. In recent years, the requirements for: material recyclability, high impact resistance,...[ Read more ]

The use of fiber-reinforced polymer composites (FRPCs), due to their excellent mechanical and geometrical properties, namely high strength to weight ratio and ease of manufacturing, has gained a great deal of attention in many industries such as aerospace, defense, marine to name but a few. Currently, the most applicable FRPC laminates are fabricated with thermosetting (TS) organic resins, which exhibit great mechanical properties with a medium curing temperature range. Nonetheless, these TS-based laminates have the significant disadvantage of poor out-of-plane properties, as they exhibit brittle behavior that can increase the susceptibility of delamination, especially in impact applications. In recent years, the requirements for: material recyclability, high impact resistance, good vibration dampening characteristics, higher fracture toughness, and post formability, prompted the development of thermoplastic (TP) FRPC laminates.

FRPC laminates with traditional TP resins, namely PEEK, Cyclic Butylene Terephthalate, Polyurethanes, require high processing temperature and costly equipment. As a result, compared to TS resins, they are rarely used. Recently, Arkema company was able to introduce Elium^® resin (a reactive methyl methacrylate (MMA) liquid TP resin), which can cure at room temperature, and moreover, is suitable for vacuum-assisted resin infusion (VARI). Considering this, in this study, FRPCs consisting plain weave ultra-high molecule weight polyethylene (UHMWPE) fiber, plain weave carbon fiber, and their hybrid systems with different stacking sequence are fabricated by VARI at ambient temperature to introduce novel TP FRPC laminates. Furthermore, a new generation of TP fiber metal laminates (FMLs) is proposed in this study which can be manufactured at room temperature. For this, titanium alloy sheets (Ti-6Al-4V) are used for fabricating hybrid titanium composite laminates (HTCLs). HTCLs have shown to enjoy better mechanical properties when compared to traditional FMLs and FRPCs, especially in the aeronautical, marine, military, and offshore applications both at room and elevated temperatures as well as harsh environmental conditions. They are outstanding in terms of stiffness, yield stress, fatigue, and high-velocity impact properties; however, there are some challenges regarding their fabrication, surface treatment, and mechanical properties. As a result, Ti-6Al-4V sheets are used to fabricate HTCLs with UHMWPE fabrics, carbon fabrics, and their hybrid FRPC systems to introduce a new generation of TP FMLs manufactured at room temperature to compare their mechanical properties with those of equivalent FRPC laminates and traditional FMLs in the literature. To investigate the feasibility of TP Elium^® resin for fabricating TP structures, ASTM standard tests of tensile, compression, shear (both intralaminar and interlaminar), flexural, and low-velocity impact (LVI) are conducted to determine the mechanical properties of the newly developed FRPCs and HTCLs with the aim of comparing the results with those of TS counterparts and also providing a more comprehensive data for theoretical analyses. In addition, fractographic analyses are performed to have a better understanding of the behavior of those new TP laminates. In addition to experimental investigations, the mechanics of structure genome (MSG) and a finite element (FE)-based micromechanics approaches are conducted to evaluate the effective mechanical properties of the TP FRPC laminates. For this end, through a two-step and the asymptotic homogenization approach, elastic properties of FRPC laminates are computed, which are compared with those obtained from experimental tests. Afterward, MSG and the commercial finite element code ABAQUS are combined to simulate the low-velocity impact behavior of the aforementioned laminates.