Experimental, Theoretical and Numerical Study of Aluminum 6061–Polyurethane Foam Sandwich Composite for Space Ground System Infrastructure

Ground infrastructure for space launch systems is designed against thermal, over pressure, acoustic and vibration loads. This paper focuses on studying the properties of aluminum–polyurethane foam (AL-PUF) sandwich composite using experiments and computational methods for precise prediction of behavior of material for space-based applications. AL-PUF panels were subjected to quarter point loaded four-point bending test to obtain the deflection for a range of loads in order to study the mechanical properties of the material. A theoretical model of four-point bending test, its associated loads and deflections are also described in this study. A computational model (FEM) of AL-PUF specimen under four-point bending test was developed to find deflection of material under a range of loads and subsequently obtain modulus of elasticity of the material. The modulus of elasticity calculated using experimental (0.53 GPa), theoretical (0.551 GPa) and numerical data (0.553 GPa) was found to be in agreement. The core shear stress and facing bending stress were obtained to be 0.20 and 14.89 MPa respectively. Further, specimens of the material were mounted to downstream of nozzle exit of a launch vehicle stage and subjected to different heat fluxes to study the behavior of material under thermal loads. A transient thermal model of the material specimen under radiative heat fluxes was developed to numerically (CFD) predict the results of experiments, and it was found that epoxy adhesive undergoes phase change including melting, burning and material degradation. The experimental data were in agreement with the results obtained numerically using CFD.