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An approach for relating the results of quantitative nondestructive evaluation to intrinsic properties of high-performance materialsOne of the most difficult problems the manufacturing community has faced during recent years has been to accurately assess the physical state of anisotropic high-performance materials by nondestructive means. In order to advance the design of ultrasonic nondestructive testing systems, a more fundamental understanding of how ultrasonic waves travel and interact within the anisotropic material is needed. The relationship between the ultrasonic and engineering parameters needs to be explored to understand their mutual dependence. One common denominator is provided by the elastic constants. The preparation of specific graphite/epoxy samples to be used in the experimental investigation of the anisotropic properties (through the measurement of the elastic stiffness constants) is discussed. Accurate measurements of these constants will depend upon knowledge of refraction effects as well as the direction of group velocity propagation. The continuing effort for the development of improved visualization techniques for physical parameters is discussed. Group velocity images are presented and discussed. In order to fully understand the relationship between the ultrasonic and the common engineering parameters, the physical interpretation of the linear elastic coefficients (the quantities that relate applied stresses to resulting strains) are discussed. This discussion builds a more intuitional understanding of how the ultrasonic parameters are related to the traditional engineering parameters.
Document ID
Document Type
Contractor Report (CR)
Miller, James G.
(Washington Univ. Saint Louis, MO, United States)
Date Acquired
September 6, 2013
Publication Date
March 1, 1990
Subject Category
Quality Assurance And Reliability
Report/Patent Number
NAS 1.26:186484
Accession Number
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.
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