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Ultrasonic analysis of bolt preloadsThis paper covers an investigation into the feasibility of analyzing bolt preloads by ultrasonic techniques. Various techniques were evaluated and a pulse echo inteferometric method was selected for experimental testing. In agreement with theoretical predictions, the interferometer response was found to be linearly related to tensile stresses oriented parallel to the bolt axis. Under rather idealized conditions, bolt loads can be determined with errors of less than 1%. The ultimate operational accuracy depends on a number of variables, such as bolt dimensions and geometry, bolt temperature, uniformity of stresses, and bolt materials, but load analyses to within + or - 3% are readily achievable. Best results are obtained with the ultrasonic transducer contact coupled to a small flat area near the center of the bolt head. The transducer can be applied and measurements made without interfering with normal wrenching operations. Prototype instrumentation is described and calibration results are tabulated for numerous bolt sizes and materials.
Document ID
19790026976
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Rollins, F. R., Jr.
(Midwest Research Institute Kansas City, Mo., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1977
Publication Information
Publication: International Advances in Nondestructive Testing
Volume: 5
Subject Category
Quality Assurance And Reliability
Accession Number
79A10989
Distribution Limits
Public
Copyright
Other

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