Nondestructive evaluation of non-ferromagnetic materials using magnetostrictively induced acoustic/ultrasonic waves and magnetostrictively detected acoustic emissions
US5457994A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1993 |
| Grant date | Oct 17, 1995 |
| Priority date | — |
| Expiry date | Mar 16, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2626
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for the nondestructive evaluation of ferromagnetic and non-ferromagnetic materials, particularly wire ropes, cables, and strands, and pipes utilizing the magnetostrictive effect for measuring minute variations in magnetic fields and characterizing these minute variations as indicative of the acoustic/ultrasonic behavior of fractures, cracks, and other anomalies within a substance under evaluation. The apparatus and method contemplate both an active testing application, wherein a transmitting sensor generates an acoustic/ultrasonic pulse within a material through the magnetostrictive effect and a second receiving sensor detects reflected acoustic/ultrasonic waves within the material, again by the inverse magnetostrictive effect. The advantages of utilizing magnetostrictive sensors as opposed to well known piezoelectric sensors lies in the ability to generate and detect acoustic/ultrasonic waves without a direct physical or acoustical contact to the material. The apparatus and method of the present invention also anticipates the use of a passive monitoring system comprised only of a receiving magnetostrictive sensor that continuously monitors a ferromagnetic or…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.