Experimental research on surface crack propagation laws for low alloy steel

✍ Scribed by Kang-Sian Lee; Len-Ji Yu; Zi-Hong Jin; Kai-Zuo Liang

• Book ID: 103069296
• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 455 KB
• Volume: 16
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(82)90039-x

✦ Synopsis

Surface crack propagation experiments were performed for low alloy steel. The testing result shows that the data for the crack propagation rate in the surface in the direction of the width may be treated by using Paris and Erdogan formula [l] for the crack propagation rate, and Shah and Kobayashi's formula for the stress intensity factor . For the crack propagation rate in the direction of the depth. the data obtained cannot be treated in this way.

It has been found that the data can also be treated by using the experimental formula suggested by Kawahara et al. .

In addition, a test for investigating through-thickness crack propagation was made. It was found that the propagation rate of the through-thickness crack is much greater than those of the surface crack both in the direction of the width and in the direction of the depth. When AK(= 100 Kg/mm"*) is the same, the propagation rate of through-thickness crack da/dN is five times as great as that of surface crack in the direction of the width.

During the propagation of the crack, the relationship between the crack length b and the crack depth a is where A = 0.97, B = 1.29.

With db/dN determined, the prediction of fatigue life can be calculated by