Hot Ground Vibration Tests

Hot Ground Vibration Tests

Ground vibration tests or modal surveys are routinely conducted to support flutter analysis for subsonic and supersonic vehicles. However, vibration testing techniques for hypersonic vehicles are not as well established due to the thermoelastic interactions that can occur when high-temperature materials are incorporated into a hot structure

that contains metallic components. In recent years, numerous high-temperature materials, new fabrication technologies, and sensors have been explored for hypersonic vehicle applications. A research team

is working to develop a high-temperature modal survey to expand the research database for hypersonics and improve the understanding of such dual-material interactions.

Work to date: Armstrong directed a program to test a carbon-silicon carbide (C/SiC) Ruddervator Subcomponent Test Article (RSTA) to support hypersonic material research. The RSTA has undergone numerous thermal, thermal-mechanical, and thermal-vibration tests. The team obtained good modal data at lower temperatures, but the off-the-shelf, high-temperature accelerometers malfunctioned on the hotter region of the test article. The experiments yielded test data that will be useful for future work and launched a high-temperature accelerometer development effort.

Looking ahead: The research team has obtained custom-made and multiple other high-temperature accelerometers and is taking steps to understand, evaluate, and characterize their complexity and functionality in preparation for future thermoelastic vibration tests.

Benefits

 Innovative: Expands the research database for hypersonics

 Pioneering: Extends the understanding of the modal characteristic effects from high temperatures on hypersonic vehicles

 Aids research: Contributes to the understanding of flutter behavior at high temperatures

Applications

 Hypersonic vehicle research and design

 Flight and Ground Experimental Test Technologies

Armstrong conducts innovative flight research that continues to expand its world-class capabilities, with special expertise in research and testbed platforms, science platforms, and support aircraft. Re-searchers place particular emphasis on providing accurate flight data for research aimed at designing next-generation flight vehicles. Described here are research projects that are seeking to increase safety, reduce costs, and dramatically decrease testing and approval times. Armstrong's new verification and validation (V&V) simulation test bench is particularly innovative as it integrates reconfigurable software models for multiple aircraft components. These models enable high-fidelity simulations to be performed more easily and at significantly faster rates than are possible with hardware-centric test benches.