Optimization Of Smart Composite Panels For Enhanced Ballistic Performance

Abstract

Composite materials offer a unique combination of properties from lightweight and high strength to long-term durability and cost-effectiveness that opens the field for their application in different industries. However, under the application of an impact load, complex distribution of stresses and strains is produced in the composite. This is because the body is heterogeneous (reinforcement, matrix, and interface) with diverse mechanical properties of the phases, which may remain constant or degrade during service. Researchers investigated different impact mitigation techniques like changing core designs to enhance load impact resistance and strength. Others examined fluid-filled barriers to mitigate the impact of ballistic loading by investigating the energy response and the energy absorption. None of the research works considered investigating the optimum structure of a fluid-filled core. This research focused on designing a composite sandwich panel with an optimum fluid-filled core. A conceptual design of a recirculation capability water-filled sandwich panel core was proposed, investigated, and optimized. Numerical experiments were conducted using Abaqus/CAE software based on experimental planning. The developed model was validated using data and information drawn from the literature. Four design variables were considered: plate thickness, spacing distances between the core shapes, volume fraction of fluid in the core, and core structure shapes. Regression analyses were used to investigate the numerical model responses and develop the regression equations used in the optimization model. Later, optimization techniques were used to determine the optimum design parameters that maximize the impact resistance using GAMS software. Results show that the water’s ability to absorb kinetic energy resulted in a delay in damage initiation and propagation. Thicker plates and closer spacing between core-core structural elements increased the stiffness of the sandwich panel, improving its blast mitigation performance. Optimization results reveal that a tubular core fully filled with water offers the best combination of properties from maximizing the elastic strain energy and minimizing the external work done, the sandwich panel mass, and cost with a plate thickness of 5 mm, core-to-core spacing of 75 mm, and volume fraction of fluid of 100%. Sensitivity analysis showed that the optimum core shape selection was sensitive to all four factors.