Energy absorption and damage mechanism of UHMWPE-aluminum composite sandwich laminate under impact loading: An experimental investigation

This study investigates impact behavior and energy absorption of a Fiber Metal Laminate (FML) made of ultra-high molecular weight polyethylene (UHMWPE) fiber composite and aluminum 2024-T3 sheets. Specimens have been tested against two types of projectiles and failure modes are compared. The effect of different thicknesses of aluminum sheets and composite core on impact performance is investigated. To examine the influence of the lay-up sequence, two types of FML including 2/1 and 3/2 configurations have been tested. The results show that increasing the thickness of the composite core increases the absorption of energy as well as specific energy absorption (SEA). The highest amount of SEA is obtained for the sample with the lowest metal volume fraction. Damage patterns show that due to the flexibility of UHMWPE fibers and ductility of Al 2024-T3, the metal and the composite core have been deformed proportionally and more energy is absorbed. This mechanism is not seen in other conventional FMLs such as glass fiber metal laminate (GLARE). Compared with aluminum sheet and GLARE under the same conditions, the proposed FML has SEA more than 3 times that of aluminum and more than 2 times that of GLARE.

Structure and Performance of Benzoxazine Composites for Space Radiation Shielding

Innovative multifunctional materials that combine structural functionality with other spacecraft subsystem functions have been identified as a key enabling technology for future deep space missions. In this work, we report the structure and performance of multifunctional polymer matrix composites developed for aerospace applications that require both structural functionality and space radiation shielding. Composites comprised of ultra-high molecular weight polyethylene (UHMWPE) fiber reinforcement and a hydrogen-rich polybenzoxazine matrix are prepared using a low-pressure vacuum bagging process. The polybenzoxazine matrix is derived from a novel benzoxazine resin that possesses a unique combination of attributes: high hydrogen concentration for shielding against galactic cosmic rays (GCR), low polymerization temperature to prevent damage to UHMWPE fibers during composite fabrication, long shelf-life, and low viscosity to improve flow during molding. Dynamic mechanical analysis (DMA) is used to study rheological and thermomechanical properties. Composite mechanical properties, obtained using several standardized tests, are reported. Improvement in composite stiffness, through the addition of carbon fiber skin layers, is investigated. Radiation shielding performance is evaluated using computer-based simulations. The composites demonstrate clear advantages over benchmark materials in terms of combined structural and radiation shielding performance.

Hybrid Self-Reinforced Composite Materials Based on Ultra-High Molecular Weight Polyethylene

The properties of hybrid self-reinforced composite (SRC) materials based on ultra-high molecular weight polyethylene (UHMWPE) were studied. The hybrid materials consist of two parts: an isotropic UHMWPE layer and unidirectional SRC based on UHMWPE fibers. Hot compaction as an approach to obtaining composites allowed melting only the surface of each UHMWPE fiber. Thus, after cooling, the molten UHMWPE formed an SRC matrix and bound an isotropic UHMWPE layer and the SRC. The single-lap shear test, flexural test, and differential scanning calorimetry (DSC) analysis were carried out to determine the influence of hot compaction parameters on the properties of the SRC and the adhesion between the layers. The shear strength increased with increasing hot compaction temperature while the preserved fibers’ volume decreased, which was proved by the DSC analysis and a reduction in the flexural modulus of the SRC. The increase in hot compaction pressure resulted in a decrease in shear strength caused by lower remelting of the fibers’ surface. It was shown that the hot compaction approach allows combining UHMWPE products with different molecular, supramolecular, and structural features. Moreover, the adhesion and mechanical properties of the composites can be varied by the parameters of hot compaction.