The calculation of the stress intensity factor K1 by the first order singular strain circular element

✍ Scribed by Hai-Ping Hu; Si-Hui Yu; Zhi-Tan Li

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 89 KB
• Volume: 16
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(82)90094-7

✦ Synopsis

A wedge-opening loading (WOL) type of specimen with an instrumented bolt has been developed which can be used to determine the threshold stress-intensity factor Klscc and the crack growth rates daldt at the same time. Strain gages were cemented on the surface of instrumented bolts. During the test, the decreasing load values can be read from the strain indicator. Thus the corresponding crack lengths as well as crack growth rates daldr can be determined from the relationship between the stress-intensity expression and the compliance characteristics of the specimen. This method has the advantages of accuracy and simplicity over other methods such as surface monitoring techniques. Using this method, this paper presents a detailed test result of K,scc and da/dr for 16 Mn steel in H$ solutions.

Another result obtained from this test is as follows: When the in-plane sizes of specimens (e.g. crack length a) are less than those of a standard test in ASTM-E399. an upper bound value of Kiscc can be determined with an oveload technique. On the other hand, a lower bound value of K,scc can be obtained while the load is within the elastic range. Therefore, it is possible to determine a range of Klscc. The concept of upper and lower bound is of practical importance