Session: 01-10-01: Structures in Extreme Environments

Paper Number: 162449

162449 - Hypersonic Weather Encounter Damage Predictions in Carbon-Carbon Composites 

Temperature-resistant structural material requirements are crucial for hypersonic aircraft design. Strict temperature requirements are well understood for space vehicles in the context of heatshields for re-entry vehicles in which surface temperatures reach as high as 1700 – 2000 K due to extremely high velocities. Supersonic and hypersonic aircraft have the same risk of experiencing extreme temperatures on the aircraft's surface that can threaten performance and safety. The surface temperature has been measured at 2200 K of a hypersonic plane flying at Mach 5 and altitude of 20 km. The flow regime has a direct effect on the temperature field, and it is known that temperatures increase drastically in the vicinity of turbulent flows. However, a recent study found that hypersonic aircraft can experience comparable temperature peaks even at a laminar flow regime. Therefore, temperature-resistant materials are essential for the sake of the safety and thermomechanical integrity of aircraft. These requirements are well beyond most metal material capabilities. Ceramics and composite materials such as carbon-carbon composites (CCC) can provide aerospace materials that are able to maintain the thermomechanical integrity of hypersonic vehicles. CCC is a composite material with carbon fibers embedded in a carbon matrix that exhibits excellent mechanical properties at elevated temperatures. For specific material selections, ceramics and CCCs can offer similar material properties in terms of low density and desirable thermomechanical performance. The advantages of using CCCs over ceramics are the design flexibility and directional customization of material properties.

Starting in the late 1970s, a series of high-speed impact damage experiments with water drops, nylon, and glass beads have been performed using aerospace CCCs, providing valuable literature data. Further experimental and computational studies mainly focused on more fundamental material characterization tests of CCCs under static conditions such as tensile or notch tension. This study investigates the damage characterization of CCCs based on publicly available data under hypersonic impact conditions at various temperatures. 

This study investigates hypersonic impact damage of waterdrop and nylon beads on CCC targets by using a non-ordinary state-based peridynamics method. A linear elastic material model with failure is chosen to computationally represent the brittle behavior of CCCs. A 3D-orthogonal CCC configuration, a common aerospace composite material, is considered. The computational model employs a strategy where each carbon fiber tow and matrix are explicitly represented as separate peridynamic materials. Preliminary peridynamic results capture sufficiently similar damage sites with the reference experimental results. Quantifications of hypersonic impact damage on CCC targets at various impact velocities will be presented. The investigation of the thermomechanical performance of CCC materials at elevated temperatures will be demonstrated to represent real-life conditions in hypersonic environments better.

Presenting Author: Ibrahim Guven Virginia Commonwealth University

Presenting Author Biography: Ibrahim Guven is an Associate Professor of Mechanical and Nuclear Engineering at Virginia Commonwealth University (VCU). He was an Assistant Professor of Materials Science and Engineering at The University of Arizona. Ibrahim spent two summers as a Faculty Fellow at the Air Force Research Laboratory. He was a Visiting Professor at the University of Rennes I, France, multiple times. Ibrahim is a recipient of the NASA Group Achievement Award for "outstanding work in developing materials for space exploration," awarded to participants of the collaborative project he worked on: US-COMP Space Technologies Research Institute.