Measuring device
US6172511A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1998 |
| Grant date | Jan 9, 2001 |
| Priority date | — |
| Expiry date | Jul 29, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M5/0083
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A device for measuring a crack in a workpiece or sample (3) comprises a resistive layer (1) arranged to be fixed to the workpiece so that the layer is fractured by the propagation of cracks in the workpiece or sample (3) to change the impedance of the layer (1). Two elongate electrodes (2) are provided on the resistive layer (1) and arranged to pass a current through it, and, measuring means are provided for measuring the impedance of the resistive layer (1), and for thereby determining the size of cracks in the workpiece or sample (3). Preferably another resistive layer (6), is provided adjacent the resistive layer (1), which is arranged not to be fractured by the propagation of cracks in the workpiece or sample (3). This enables environmental effects to be compensated for.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.