An overview of smart structures research currently underway at the NASA Langley Research Center in the areas of aeroservoelasticity and structural dynamics is presented. Analytical and experimental results, plans, potential technology pay-offs, and challenges are discussed. The goal of this research is to develop the enabling technologies to actively and passively control aircraft and rotorcraft vibration and loads using smart devices. These enabling technologies and related research efforts include developing experimentally-validated finite element and aeroservoelastic modeling techniques; conducting bench experimental tests to assess feasibility and understand system trade-offs; and conducting large-scale windtunnel tests to demonstrate system performance. The key aeroservoelastic applications of this research include: active twist control of rotor blades using interdigitated electrode piezoelectric composites and active control of flutter, and gust and buffeting responses using discrete piezoelectric patches. In addition, NASA Langley is an active participant in the DARPA/ Air Force Research Laboratory/ NASA/ Northrop Grumman Smart Wing program which is assessing aerodynamic performance benefits using smart materials.

Summary

Abstract. Split Hopkinson Tension Bar (SHTB) experiments can be used to test the material behavior with high strain rates in tension loading. The influence of the specimen mounting and the specimen design on the test results was investigated. Three mounting methods were tested. The best signal is achieve using a mounting based on form fit. The three tested specimen designs all lead to a valid fracture behavior, but result in a different local strain rate.

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