Creep-Fatigue Crack Growth Using Digital Image Correlation
Creep-fatigue crack growth tests are cyclic tests that have a hold period at the maximum load. This hold period, or dwell, is the period during the test when the time-dependent mechanisms operate. The length of the dwell period has been shown to affect the fatigue crack growth rate. During the hold period, crack tip blunting (due to creep deformation) and crack extension can be measured using 2-D digital image correlation (DIC). DIC requires a random speckle pattern on the flat surface being investigated. The speckle pattern is a unique pattern and, as the surface is strained, locations on the pattern will move to new positions relative to a previous strained condition. The images are compared and an algorithm calculates the strain. The camera can be positioned to view the crack tip and measure crack extension and crack opening displacement (COD). This provides a means by which the crack tip creep deformation can be determined during the hold period, providing valuable information regarding the crack tip kinetics and crack driving force. This paper will evaluate this technique for creep-fatigue crack growth measurements and provide preliminary data for a Ni-base alloy.
Creep-Fatigue Crack Growth Digital Image Correlation
Jeffrey L. Evans
Department of Mechanical and Aerospace Engineering,University of Alabama in Huntsville,Huntsville,Alabama 35899,USA
国际会议
北京
英文
1-6
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）