Carbon fibber reinforced polymer use in space launch vehicle propellant tanks - concept and finite element method study

Abstract

Weight reduction is a never-ending goal in aerospace engineering, especially for a space launch vehicle (SLV), were every gram of mass has a penalty in the vehicle's performance. Since propellant tanks generally weigh more than half of the dry mass of a SLV, it is particularly advantageous to implement composite materials in their construction. Yet, difficulties with oxygen compatibility, permeability and manufacturing maturity dictate that aluminium alloys with high lithium content are still the state of the art in this field. Recent developments in the aerospace composites industry are starting to change this perception, especially regarding Carbon Fibber Reinforced Polymer (CFRP) application. Hence this study, which aims to propose an integral CFRP propellant tank concept and determine mass savings by comparing it to a metallic baseline, through finite element method (FEM) analysis with simulated flight loads. Tank dimensions, geometry and loads were chosen for micro-satellite SLV application. Also, Altair's Optistruct solver was used for FEM calculations, with Altair's HyperWorks for pre and post-processing. A mass reduction of close to 35% has been obtained with comparison to the metallic baseline design for the same boundary conditions. Therefore, a sound and competitive design for a micro-satellite SLV propellant tank has been successfully achieved.