High cycle fatigue approach based on affected depth and considering the secondary dendrite arming spacing (SDAS) effect for a defective A356-T6 alloy

Effect of fisheye failure on material performance inducing error circle under high cycles

“…The above "fisheye" internal crack growth life estimation method does not reflect the joint effects of defect size and depth on high cycles/ultra-high cycles material performance. Some studies have shown that the defect depth has an effect on material performance (Nasr et al, 2018;Parant et al, 2020;Pereira et al, 2019;Sakai et al, 2002). The Murakami fatigue strength model was introduced into the Tanaka Murakami model, and the high cycle fatigue life model was established.…”

“…The formula (7) does not reflect the joint effect of defect size and depth on high cycle and ultrahigh cycle material performance. Some studies have shown that the defect depth has an effect on material performance (Nasr et al, 2018;Parant et al, 2020;Pereira et al, 2019;Sakai et al, 2002). To consider the influence of Vickers hardness, defect size and depth on high cycle fatigue life, we established high cycle fatigue life model by introducing Murakami fatigue strength model into Tanaka-Mura model, the model is closer to the actual state of the material, making the prediction of material performance more accurate.…”

“…Romano et al (2020) investigated the effect of surface quality and sub-surface porosity on high cycle fatigue behavior of 17-4 precipitation hardening (PH) stainless steel (SS) fabricated. Nasr et al (2018) proposed a new method to predict the high cycle fatigue behavior of A356-T6 alloy, which considered the artificial and natural defects.…”

“…If the life prediction is only based on the size of inclusions and does not consider the failure mechanism of ultra-high cycle fatigue, the prediction results are more dangerous (Chapetti et al, 2003). Studies have shown that the specific location of defects also has an impact on high cycle fatigue life (Chapetti et al, 2003;Nasr et al, 2018;Sakai et al, 2002). In previous studies, the effect of defect depth on high cycle fatigue life was obtained by summarizing the law between them through experiments, and there is no specific mathematical model to reflect the influence.…”