Double-cantilever beam type test piece and corrosive environmental crack growth measuring apparatus
US5317925A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1991 |
| Grant date | Jun 7, 1994 |
| Priority date | — |
| Expiry date | Mar 18, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2203/0617
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A corrosive environmental crack length measuring apparatus including a double-cantilever beam type test piece having a tapered portion in a portion where the crack grows, a slit, and at least two holes, with the test piece being placed within a corrosive environment. Leads inserted in the holes of the test piece to be spot-welded thereto to supply a direct current to the holes. A current polarity switching device is provided with, a stabilized direct current power supply connected with the direct current supplying leads through the current polarity switching device. Potential difference measuring leads are inserted in holes formed in two outer faces of the double-cantilever beam type test piece parallel to a section of a crack growing portion at a plurality of points along the crack growing direction so as to be spot-welded thereto. A multiplexer is provided with, a micro-voltmeter connected with the potential difference measuring leads through the multiplexer, and an arithmetic unit judges crack length based on ratios between potential differences measured by switching the polarity of direct current using the current polarity switching device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.