Abstract

The effects of specimen geometry on the initiation and growth of ductile fracture from fatigue precrack have been investigated. Tests were made on the center-notched specimens with 5mm side ligament (specimen-CN5) and the side-notched specimens with the ratios of the ligament to notch depth, 5mm/22.5mm, 10mm/20mm, and 20mm/15mm (specimen-SN5, -SN10, and -SN20, respectively). Of these specimens, the stress triaxiality was largest in Specimen SN5 and smallest in CN5. 3 point bend specimens and CT specimens were also used as the standard specimens.Specimen-CN5 has shown the largest δi and Specimen-SN5 the smallest δi and Ji, whereas δi's and Ji's of other specimens have shown about the same values, where δi and Ji are COD and J at ductile crack initiation, respectively. Though the effect of specimen geometry on the ductile crack “initiation”was obvious in the above results, the effect on ductile crack“growth”was not clear in the present tests. The result that COD at the crack tip decreased from δi to δp as the crack grew from the precrack tip was explained by considering the effect of plastic strain-stress triaxiality history at each point of fracture until ductile fracture occurred at that point.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.