Fatigue Limit Evaluation of Blunt-Notched Specimen Using ΔKthValue of Small Crack

✍ Scribed by T. Matsueda; H. Noguchi

• Publisher: Elsevier
• Year: 2011
• Tongue: English
• Weight: 403 KB
• Volume: 10
• Category: Article
• ISSN: 1877-7058
• DOI: 10.1016/j.proeng.2011.04.168

✦ Synopsis

It is the big problem to evaluate the fatigue limit σ w in order to safely design structures and machines. Under the condition of the fatigue crack initiation limit σ w1 , the present author defined the initial crack scale √area using the characteristic elastic field of the notch, the half length of the fatigue crack a and a notch depth t. Using this√area, the methods of calculating ΔK th and σ w1 were proposed. In addition to it, in this condition it is made sure that ΔK th exists on the band from ΔK th prediction line of the micro fatigue crack [1] within 18% error. Using ΔK th calculated by the prediction line and the value of√area, this evaluating method of σ w1 was confirmed with annealed 0.35% carbon steel. As a result, it was confirmed that this method to evaluate σ w1 is within 18% error. Moreover it was also confirmed that the σ w1 value by this prediction method is within 10% error when the predicted σ w1 value is greater than σ w2 .