The Strain Sensor consists of a strain gauge based extensometer type sensor connected to a PC. The computer and sensor amplifier are battery powered. The sensor is pressed or clamped on to the object to be inspected, offering cost effective insitu measurements. The data, which is stored in DOS/Windows-format, accomplish data analyses such as vibration amplitude or Fouria analyses on-line through computer colour screen or later printouts.
 Fig.: The Dynamic strain Analysis Device |
Based on a number of fatigue tests keeping a constant middle tension while varying the dynamic stress, a Wöhler-curve can be designed. This curve will indicate connection between the stress amplitude and the number of load-cycles before break. This will depend of the type of material, load and the average stress. Due to the compact size and low weight, the method easily cover large areas. There is no need for removal of painting
Having the material data available, the computercalculates the measured stress and frequency data to actual engineering values, comparing the obtained results with the stress limits.The eventual findings will form the basis for proposals for design modifications or life time analysis.
Det Norske Veritas has available a prototype of the Strain Analysis Device which has been used offshore in the North Sea to examine pipe supports and process equipment in a process plant. Due to the equipment's mobility, large areas on piping can be inspected. After the survey, the components exposed for stress will be an object for further thorough examination.
Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00
Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:
Publication Contact:
7th ECNDT, Park Alle 345, DK-2605 Broendby, Denmark, Fax: +45 46 26 70 11, Email: 101373.3414@compuserve.com
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