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Back-face strain for monitoring stable crack extension in precracked flexure specimens
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Ghosn, Louis J. Salem, Jonathan A. |
| Copyright Year | 2010 |
| Description | Calibrations relating back-face strain to crack length in precracked flexure specimens were developed for different strain gage sizes. The functions were verified via experimental compliance measurements of notched and precracked ceramic beams. Good agreement between the functions and experiments occurred, and fracture toughness was calculated via several operational methods: maximum test load and optically measured precrack length; load at 2 percent crack extension and optical precrack length; maximum load and back-face strain crack length. All the methods gave vary comparable results. The initiation toughness, K(sub Ii) , was also estimated from the initial compliance and load.The results demonstrate that stability of precracked ceramics specimens tested in four-point flexure is a common occurrence, and that methods such as remotely-monitored load-point displacement are only adequate for detecting stable extension of relatively deep cracks. |
| File Size | 1971581 |
| Page Count | 28 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20100024331 |
| Archival Resource Key | ark:/13960/t56f0tv8h |
| Language | English |
| Publisher Date | 2010-05-01 |
| Access Restriction | Open |
| Subject Keyword | Nonmetallic Materials Toughness Stability Length Calibrating Strain Gages Ceramics Fracture Strength Detection Loads Forces Crack Propagation Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
