Proceedings of a Workshop on Materials State Awareness (2008) / Chapter Skim
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Session I: Key Issues for Materials State Awareness
Session I: Key Issues for Materials State Awareness
Pages 3-8
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of aircraft engines, airframes, and helicopter drive trains. To accomplish this, the program focuses on uncertainty management by first exploiting existing sensor technology to define current materials state awareness and then incorporating physics-of-failure models to predict the future evolution of damage accumulation.
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Since then, resin porosity, thermal damage, and ultraviolet degradation prompted studies associated with macro- and micromechanical breakdown of the resin, fiber/resin interfacial properties, and fiber breakage. Specialty materials, such as ceramic-based thermal protection systems and polymericbased observable materials, may not be critical to the structural integrity of the airframe; however, they are critical to the mission performance of the vehicles for which their use is intended.
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Successful implementation of a materials state awareness program also requires close collaboration between the physicist developing sensor technology, the materials specialist who understands material properties and their impact on the structure, the structural analyst who can identify failure modes and define acceptable limits, and the NDE specialist who understands the measurement principles and applications and would serve as the technology integrator. Often, each of these disciplines operates in a silo, not fully communicating key information required for seamless transition.
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As an example, superalloy turbine airfoils that continually operate in a high-stress, high-temperature environment offer a significant opportunity for benefit from MSA; in this case, the degradation modes are dominated by the thermal history of the blade, and hence accurate surface-temperature measurement across the airfoil is particularly critical to MSA success. Research and development opportunities to advance MSA include the following: Furthering the fundamental understanding of material degradation modes, especially those of advanced materials targeted for production applications; historically this work has not been well funded;
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NDE methods must measure physical changes in a material that in turn can be physically linked to the progress of degradation modes. A systems approach is necessary to selecting sensors, developing reasoner software, and designing hardware that can be suitably interrogated by MSA methods.
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