Effect of short fatigue cracks on plane strain fracture toughness

✍ Scribed by C.N. Freed

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 159 KB
• Volume: 1
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(70)90012-3

✦ Synopsis

AN IMPORTANT feature of the fracture mechanics approach to fracture toughness is the introduction of a fatigue crack at the notch tip of the specimen. For the fatigue crack to represent the Raw or crack which will exist in a structure, two conditions must be met: The crack must be formed in the specimen using a low stress intensity range AK so that the crack tip will attain a degree of sharpness such that still greater sharpness does not additionally decrease the critical K for onset of rapid fracture; and the fatigue crack should be long enough so that an additional increase in its length would not cause the K,, measurement to decrease. This note deals with the extent to which Krc values are affected by fatigue cracks generally considered too short for valid measurements. A comparison is made of fatigue cracks longer and shorter than the suggested minimum of 0.05 in. [ 1 I.

The fatigue crack length comparison was performed on side-grooved single-edge-notched (SEN) tension