Notable size effects on very high cycle fatigue properties of high-strength steel

Verification of selected models of the size effect based on high-cycle fatigue testing on mini specimens made of EN AW-6063 aluminum alloy

“…The probability of material defects resulting in fatigue crack increases with the specimen volume (Kocańda and Szala, 1997). The effect was proven in the experimental studies on small specimens (Furuya, 2011;Haftirman, 2009;Hirose et al, 2000) confirming that metals are sensitive to changes in the cross-section. Figure 1 shows the size effect test results for aluminum alloys.…”

Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint

“…In VHCF regime, the fatigue strength of the NZ is still higher than that of the full specimen, even when the failures of full specimens occur at the NZ. This can be ascribed to the difference of specimen dimensions because the risk volume (specimen volume subjected to a stress amplitude larger than the 90% of its maximum value [24,25]) of the NZ specimen in this test is much smaller than that of the full specimen. Generally, a larger risk volume results in a smaller fatigue strength, so the fatigue behaviors of the NZ are slightly better in this test.…”

Gaussian specimens for VHCF tests: Analytical prediction of damping effects

“…Recently, size-effect gained significant attention. In particular, specimens with different risk-volumes (specimen volume subjected to a stress amplitude larger than the 90% of its maximum value) were investigated [9][10][11]. Experimental results showed that, in case of high-strength steels, the larger the risk-volume the smaller the fatigue strength.…”