Coupled aerothermoelastic, or fluid-thermal-structural interaction (FTSI), behavior is a necessary consideration for high-speed vehicles when assuming a ‘hot-structure’ design philosophy. Hot-structures, versus thermally protected ones, are weight-constrained (thinner-gauge metallic or composite) with (in-plane) confining sub- and surrounding structure. These constraints, along with the extreme and transient thermal and aero-induced loadings, result in nonlinear structural behavior that can be very challenging to predict. These prediction challenges manifest in uncertain and quite possibly non-conservative limit-state margins. All of these issues conspire to obstruct the fielding of a hypersonic weapon system, whether single-use or reusable. To alleviate these challenges, the USAF Structural Sciences Center (SSC) at Wright-Patterson AFB has been actively pursuing a number of unique and consequential FTSI experiments. The design and observations of these experiments has resulted in several validation challenge problems for the larger industry, academic and laboratory communities, and complete datasets are available for distribution by the SSC. The SSC has continued to pursue research relevant to hot-structures – designing/refining a series of experiments, measurement techniques and predictive capabilities with ongoing activities in the AEDC VKF-C, AFRL RQ Mach 6 High Reynolds Number Facility (M6HRF), the RQ Supersonic Scramjet Research Facility 19 (RC-19) and the NASA Langley High Temperature Tunnel (HTT). Recent results from these experimental campaigns will be shared to motivate FTSI research and provide greater context for collaboration with the aerothermoelastic research and technology communities.
About the speaker:
Dr. Stephen ‘Michael’ Spottswood is a member of the senior technical staff of the Air Force Research Laboratory, Aerospace Systems Directorate (AFRL/RQ), at Wright-Patterson Air Force Base, Ohio, and a Principal Aerospace Engineer in the Structural Sciences Center (SSC), where he leads a highly capable government, post-doctoral and academic research team. As a long-serving member of the SSC, Michael has led numerous basic-to-advanced development projects/programs and made lasting connections with the aerospace industry. He was the technical manager for the first SSC-led academic collaborative center – the Midwest Structural Sciences Center, U. of Illinois, Urbana-Champaign, 2006-2013. In 2012, Michael was selected to head the basic research mission of the SSC, leading the AFOSR interactions and forging strong connections with Arlington, EOARD and AOARD program officers. Michael’s SSC aerothermoelastic research team is well recognized for their hypersonic structures research, e.g., 1st ever successful high-supersonic full-field observations/validation of aerospace structure at the Arnold Engineering Development Center (AEDC) von Kármán aerothermal wind tunnel (VKF-C). Michael excels at leading diverse teams focusing on multi-discipline aerospace problems, and enjoys designing and executing complex experiments exploring deleterious structural behavior and then reconciling predictions and measurements. Michael was the first USAF recipient of the Presidential Early Career Award for Scientists and Engineers (PECASE, 2010), a 2015 AFRL Commander’s Cup/Richard Neal Special Recognition Award winner, 2017 Courtland D. Perkins Award winner, 2022 S.D. Heron Award winner, and was recently named a Fellow of the American Society of Mechanical Engineers.