Volume 1, Issue 1 (January 1973)
Direct Nondestructive Prediction of Engineering Properties
Quantitative nondestructive evaluation provides the means for directly predicting engineering properties of materials on individual components. Through proper problem definitions, the working concept of material ↔ energy interaction, and multifunctional/multivariable relationships, a complex material system can now be characterized in terms of both bulk and constituent properties as they actually exist in the finished product. In fiber-reinforced composite materials, properties such as in-plane tension/compression elastic modulus, at any polar angle, or in the thickness direction; shear modulus; poisson's ratio; density; volume fractions of fiber, matrix and porosity; and fiber elastic modulus may be pinpointed. In adhesively bonded joints, where failure mode is brittle fracture at or near the interface, bond adhesive strength may be predicted from nondestructive measurements of substrate surface free energy, contact angle, and bondline thickness, when the reference liquid surface free energy, effective strain, and stress-strain integral are known.