Automated Measurement of Crack Length and Load Line Displacement at Elevated Temperature,
Abstract
Test results in the literature show that, in creep cracking tests at elevated temperature under steady load, the crack growth rate correlates best with the contour integral C, also called J*, in comparison to other possible parameters. In the case of the fatigue at elevated temperature, the crack growth rate correlates best with C* if cracking is predominantly time dependent. If, however, cracking is predominantly cycle dependent the crack growth rate correlates best with the range delta J of the contour integral J. It is discussed that in such testing C* and J are fairly easily determined if, apart from load and crack length, the load line displacement is measured. A description is given of a test set-up developed for elevated temperature creep cracking tests in which crack length was measured with the electrical potential drop method and load line displacement was measured with two inductive transducers located inside the furnace. Measurement was automated with the aid of a personal compute which controlled the measurements and processed the results automatically. This set-up can be adapted for elevated temperature fatigue testing. Keywords: Creep tests; Crack propagation; High temperatures; Automatic control; Fatigue tests.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1988
- Accession Number
- ADA194402
Entities
People
- F. F. Groep
- H. P. Van Leeuwen
- L. Schra
- N. Dam
Organizations
- AGARD