Solid Mechanics Research for Quantitative Non-Destructive Evaluation -

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Résumé :
1. DOD Interests in QNDE.- 1.1 Naval Ship System Requirements in Quantitative Nondestructive Evaluation.- 1.2 Air Force Requirements for NDE of Composites.- 2. Acoustic Emission.- 2.1 Acoustic Emmision: a Quantitative NDE Technique for The Study of Fracture.- 2.2 Applications of Quantitative AE Methods: Dynamic Fracture, Materials and Transducer Characterization.- 3. Defect Characterization by Scattering Methods.- 3.1 Flaw Characterization by Ultrasonic Scattering Methods.- 3.2 Experimental Research of Ultrasonic Scattering from Discontinuities.- 4. Fracture Mechanics and QNDE.- 4.1 Application of QNDE to Retirement-for-Cause Analysis.- 4.2 Elastic Wave Interactions with Partially Contacting Interfaces: Status of Theory and Application to Fatigue Crack Closure Characterization.- 4.3 Ultrasonic Nondestructive Evaluation, Microstructure and Fracture Toughness Interrelations.- 5. Acoustic Microscopy.- 5.1 Acoustic Microscopy of Surface Cracks: Theory and Practice.- 5.2 QNDE using Low-Frequency Acoustic Microscopy.- 6. Qnde of Composite Materials.- 6.1 Ultrasonic NDE of Composites - A Review.- 6.2 Nondestructive Characterization of Impact Damage in Graphite/Epoxy Laminates.- 6.3 Characterizing the Damage State of Composite Laminates VIA the Acousto-Ultrasonic Technique.- 7. Thermal Wave Imaging.- 7.1 Thermal Wave Imaging for Quantitative Nondestructive Evaluation.- 8. Qnde of Material Properties and Residual Stress States.- 8.1 Theory of Acoustoelasticity and Acoustoplasticity.- 8.2 Ultrasonic Measurement of Residual Stresses.- 8.3 Low-Field Magnetoacoustic Residual Stress Measurement in Steel.- 8.4 Ultrasonic Determination of Texture and Residual Stress in Polycrystalline Metals.- 9. Contributed Papers.- 9.1 Analytical Considerations for Inelastic Zone and Crack GrowthCharacterizations.- 9.2 A Comparison of Several Ultrasonic Techniques for Absolute Stress Determination in the Presence of Texture.- 9.3 Ultrasonic Scattering and NDE of Materials and Cracks.- 9.4 Hybrid Ray-Mode and Wavefront-Resonance Techniques for Acoustic Emission and Scattering in Multiwave Layered Media.- 9.5 Monitoring Elastic Stiffness Degradation in Graphite/Epoxy Composites.- 9.6 Mechanical Modeling and Measurements on Fibrous Composites.- 9.7 Acoustic Emission Source Characterization of Microcracking in A533b Steel.- 9.8 Diffuse Field Decay Rates for Material Characterization.- Epilogue They Met to Argue NDT.- List of Attendees....

Sommaire:
Within the Solid Mechanics Program at the Office of Naval Research (ONR), our primary mission is to establish a basic research program which addresses the funda? mental issues in solid mechanics where a clear scientific understanding is lacking. Our approach involves first identifying the various scales at which material and structural response and failure occur. Within each level of behavior we address the basic mechanical phenomena for which a clear physical description is not available. ONR's program emphasizes experimental research to identify and quantify the interacting behavior and response mechanisms. Theoretical and computational approaches are developed to explain the details of the physical processes and to establish the technology necessary to control the thermomechanical behavior of materials and structures. Within the Department of Defense, it is a natural evolution that all new systems must generally operate in more demanding environments than the systems they replace. Thus, structural designers are pushed towards lighter weight, precision structures utilizing new materials. In such an environment, structural design mar? gins simultaneously shrink and become more critical. Such trends make it essential that a well founded scientific base for the nondestructive detection and assessment of subcritical flaws in structural materials and structures exist. Within the ONR Solid Mechanics Program we are interested in both the identification of flaws and assessment of their degree of criticality....