The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 05, 1985
Filed:
Jul. 12, 1983
Hegeon Kwun, San Antonio, TX (US);
Cecil M Teller, II, San Antonio, TX (US);
Southwest Research Institute, San Antonio, TX (US);
Abstract
This disclosure relates to a nondestructive method of measuring stress in a ferromagnetic structural material. One method involves the measurement of the change in ultrasonic velocity induced by an externally applied magnetic field; the method enables nondestructively determining the magnitude, the direction, and the sign (i.e., tensile or compressive) of a stress in a ferromagnetic material. The magnetically induced velocity change of an ultrasonic wave is caused by the magnetoelastic coupling in the ferromagnetic material. This magnetically induced velocity change is characteristically dependent on the magnitude and the sign of the stress and also on the relative orientation of the stress, the magnetic field, and the polarization and propagation direction of the ultrasonic wave. The dependence of magnetically induced velocity changes can be utilized for nondestructive stress measurements. In one version, for measuring bulk stresses, either a longitudinal ultrasonic wave or a shear ultrasonic wave is used. In another version, for measuring surface stresses, a surface ultrasonic wave is preferably used. By using surface waves at several different frequencies, a stress gradient can also be determined.