Fatigue crack closure under triaxial stress constraint. 1: Experimental investigation

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Engineering Fracture Mechanics

OSTI ID:85471

Wanlin, G ^[1]

---

1. Xian Jiaotong Univ., Xian (China)

Experimental investigation has been done for fatigue crack closure in 7050-T7451 aluminum alloy and 30CrMnSiNi2A high strength steel. CT specimens with thicknesses of 2, 3, 4, and 8 mm are used and four techniques of closure measurement are adopted in the test, namely the COD-load compliance technique, back face strain-load compliance technique, near tip strain gauge technique, and the indirect technique based on fatigue crack propagation rate (FCPR) measurement. The uncertainties associated with different techniques of closure measurement as well as the thickness effects are analyzed. It is shown that the global-compliance based methods cannot reflect the shielding effect of closure upon the crack tip strain intensification sufficiently. The near tip strain gauge method is more sensitive and can give a better result if the gauge lies in an optimum position. For materials in which the striation mechanism is dominant the indirect methods based on FCPR or fatigue striation measurement can predict the closure level very well. 12 refs.

• OSTI ID: 85471
• Journal Information: Engineering Fracture Mechanics, Journal Name: Engineering Fracture Mechanics Journal Issue: 2 Vol. 49; ISSN 0013-7944; ISSN EFMEAH
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
FRACTURE MECHANICS
MATERIALS
MATHEMATICAL MODELS
STRAIN GAGES