Measurement of fatigue crack closure through electron microscopy

Effects of Shot-Peening and Stress Ratio on the Fatigue Crack Propagation of AL 7475-T7351 Specimens

“…Sci. 2018, 8,375 3 of 14 regime with crack growth data obtained by the K-decreasing method, measured opening loads were excessive. This discrepancy was justified by Paris et al [24], who suggested the "partial closure model".…”

Crack front curvature: Influence and effects on the crack tip fields in bi-dimensional specimens

“…Apparently, crack closure is a 3D mechanistic phenomenon. Experimental observations [19,20] and numerical analysis [16] shows that fatigue cracks open first at midthickness and later at the surface, which often leads to curved crack fronts for through cracks [21]. Branco et al [22] analysed numerically, the influence of the crack closure in the stable crack shape growth and compared the results when the crack closure was not considered.…”

The application of small overloads for fractography of small fatigue cracks initiated under constant-amplitude loading

“…6a was preceded by a block of a low number of cycles with a decreasing minimum stress. This is a procedure proposed by Sunder and Dash [9] for deriving an indication of the crack closure level from the striation spacing of these cycles. In the first cycles of this block the striation spacing increases, but as soon as the spacing becomes constant it is assumed that the corresponding S min value is equal to the crack closure stress level (S cl ) which thus can be obtained.…”