Carbon fiber reinforced plastics with aluminum honeycomb core design methodology for space and surface mining applications

Abstract

The space mining market is expected to grow in the future with water, gold, and platinum as just a few of the resources that could be accessible in the Moon or in near-Earth asteroids. To achieve this mining capability, sandwich composites offer an optimum structure for space mining vehicles due to their relatively high strength and stiffness compared to their weight. The challenge of designing such structures is often hampered by the lack of design approaches for practicing engineers in the mining industry usually lacking the composite material expertise or access to significant test capabilities. Expanding the use of sandwich composite materials into this industry requires selection charts that fully define the material system for a design engineer. Currently there is no methodology that systematically allows a design engineer to define a material system that uses carbon fiber reinforced plastics with aluminum honeycomb cores. The purpose of this paper is to introduce novel selection charts that allow an engineer to define the number of plies, stacking sequence, core thickness, and core density of a sandwich composite based off the moment carrying capacity. An example implementation of this approach is conducted using a carbon-fiber/epoxy with an aluminum alloy 5052 core. The selection charts developed with this approach are than validated with experimental analysis in accordance with ASTM D7249 (Standard Test Method for Facing Properties of Sandwich Construction by Long Beam Flexure). Experimental results show strong correlation with the selection charts by predicting the available moment and the mode of failure. Such selection charts will help facilitate wider use of these materials into industries that do not currently use them. Additionally, a novel numerical modeling approach for thick section sandwich composites using 3D finite elements is introduced. This approach shows how sandwich composite facesheets can be modeled with standard 3D elements instead of elements that support layers. Such an approach allows access to a wider variety of elements and is conducive to rapid design iterations when topological changes are occurring such as in a research and development environment. It is shown that numerical results correlate well with experimental data when using a linear-elastic isotropic core model with bilinear isotropic plasticity.