Mechanical properties nondestructive evaluation

Inspection is usually done by nondestructive techniques. This is usually known as nondestructive examination (NDE). The general term nondestructive evaluation describes the various terms used such as nondestructive inspection (NDI), nondestructive testing (NDT) and nondestructive examination (NDEx). Some of the aspects or purpose of these techniques involve detection and evaluation of flaws, leaks, dimensions, location (position), microstructures, mechanical properties and stress. 

The quality of eucalypt woods for producing chemical pulps was evaluated using NIR spectra and chemometric methods [124]. NIR spectroscopy was used to predict pulp yield and cellulose content from spectra of powdered wood samples [137]. In another application, in addition to estimating lignin content, NIR spectra were used to quantify hardwood-softwood ratios in paperboard [138]. NIR spectra taken from solid European larch samples subjected to axial bending and compression tests revealed an excellent ability to model the variability of mechanical properties [139]. The study demonstrated that the model is based not only on the measurement of density, but also on surface geometry, composition, and, possibly, lignin content. The authors concluded that NIR spectroscopy shows considerable potential to become a tool for nondestructive evaluation of small clear wood specimens, e.g., increment cores. 

ANTHONY G. EVANS is the Gordon McKay Professor of Materials Engineering at Harvard University. His research interests include the mechanical properties of brittle materials particularly the fracture of ceramics under conditions of impact thermal and mechanical stress and failure prediction based on nondestructive evaluation. He is a recipient of the American Ceramic Society s Ross ColEn Purdy Award and has authored and co-authored several publications. Dr. Evans is a member of the National Materials Advisory Board and has served on several National Research Council committees. Dr. Evans was elected to the National Academy of Engineering in 1997 for his contributions to the development and understanding of structural materials. 

Hardness is used in identification, classification, and quality control. Hardness tests provide a rapid evaluation of variations in mechanical properties affected by changes in chemical or processing conditions, heat treatment, microstructure, and aging. Since the hardness test usually produces an insignificant permanent change in the specimen, it is considered to be a nondestructive test. 

Analysis for physical properties and mechanical properties difficult, analysis for damping efficiency has not reached a consensus Nondestructive testing tedious Acceptable methods for evaluation of residual properties have not reached a consensus... 

D. F. Adams, Test Methods for Mechanical Properties, Comprehensive Composite Materials, Vol. 5 Test Methods, Nondestructive Evaluation, and Smart Materials, Leif Carlsson, Robert L. Crane and K. Uchino, Vol. Eds., Anthony Kelly and Carl Zweben, Editors-in-Chief, Pergamon Press, Elsevier Science Ltd., Oxford, 2000. 

Non-destructive test (1) A test that yields information about failure under mechanical stress without actually stressing to failure. (2) More broadly, any test to evaluate a property of a material, part, or structure that does not significantly damage the part. Techniques used include ultrasound, magnetic inspection of metals and welds. X-ray inspection, infrared, nuclear magnetic resonance, and sonic analysis. Although an indentation-hardness test leaves a permanent mark, in many tests of parts it is nondestructive. 

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