Thermo-Structural Analysis of 3D Composites for Reusable Vehicle Applications

Reusable launch vehicles are designed for multiple missions and it undergoes severe aerodynamic loading conditions during its operation. Nosecap is one such hot structure in a reusable vehicle, which is a doubly curved conical structure whose cross-section varies with respect to height. Carbon-Carbon composite is mainly used in these hot environments. Generally the 3D composite structures for the hot structures are made from 3D textile preforms. The Nosecap experiences high temperature variations during the re-entry phase of the flight. Heat transfer analysis and thermo-structural analysis of the Nosecap are essential for estimating the design margins. The output of heat transfer analysis, which is the temperature distribution with respect to time, will be added to the corresponding pressure loads for carrying out thermo-structural analysis. Analytical methodology has been arrived at based on Representative Unit Cells for evaluating the 3D composites properties from the basic unidirectional material properties. In the present study thermo-mechanical properties of 3D Carbon-Carbon composite has been determined and selection of the best suitable textile preform has been addressed based on heat transfer and thermo-structural analysis of Nosecap using the finite element software NASTRAN. A total thermo-structural design procedure has been presented with the support of suitable numerical investigations.