Monitoring Fatigue Crack Initiation and Propagation in Cruciform Joints Using Resistance-Type Gages

    Volume 32, Issue 1 (January 2004)

    ISSN: 0090-3973

    CODEN: JTEOAD

    Page Count: 6


    Johan Singh, P
    Scientific Officer, Indira Gandhi Center for Atomic Research, Kalpakkam

    Thomas, G
    Scientific Officer (retired),

    Guha, B
    Associate Professor, Professor, Indian Institute of Technology, Madras, Chennai

    Achar, DRG
    Associate Professor, Professor, Indian Institute of Technology, Madras, Chennai

    (Received 6 September 2002; accepted 10 June 2003)

    Abstract

    The monitoring of fatigue crack initiation and propagation in cruciform joints is very complex and time consuming. The amount of technical information generated by a single fatigue test can vary from a terse noting of the cycles to the point till the specimen breaks, to a continuous observation of crack lengths. A wide variety of experimental methods are available to study the changes in bulk properties taking place in a test specimen (with simple geometry) while it is subjected to alternating stresses. However, in many fatigue test situations (for instance, in cruciform joints), it is very difficult to monitor the changes due to multiple possible crack initiation points. In this paper, a method has been developed to monitor the crack initiation for cruciform joints with different geometry by resistance-type strain gages. Also, the application of a relatively new, thin-film bondable transducer, commercially available under the name ‘crack propagation gage,’ was evaluated for fatigue crack propagation tests for cruciform joints at room temperature. Additionally, the strain gage and the crack propagation gage instrumentation system can be used for direct test machine control, permitting completely automated fatigue crack growth testing.


    Paper ID: JTE12185J

    DOI: 10.1520/JTE12185J

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    Author
    Title Monitoring Fatigue Crack Initiation and Propagation in Cruciform Joints Using Resistance-Type Gages
    Symposium , 0000-00-00
    Committee E28