• Nikbin, Kamran M.
• Davies, Catrin M.
• Kim, Yun Jae
• Mehmanparast, Ali
• Kim, Nak Hyun

Abstract

<p>Discontinuous cracks ahead of the leading crack tip may be present in observedcertain creep crack growth tests as well as in components. In this work, a single crack of different dimensions and distance from the leading crack has been numerically modeled in a compact tension specimen using elastic, elastic-plastic and elastic-plastic-creep loading. In order to examine their effects on fracture mechanics parameters a sensitivity analysis was performed to determine the effects of size and distance of the secondary crack with respect to the main crack. t The elastic analysis shows that the compliance is insensitive small cracks ahead of the main crack. Limit load analyses, assuming an elastic-perfectly plastic material, show that the limit load decreases due to the presence of discontinuous cracks ahead of the main crack. Theload versus plastic load-line displacement response of the specimen was significantly influenced by discontinuous cracking. The J contour parameter and C ^*-integral have been evaluated at the three crack tips and the average of all of them derived for the appropriate contours were compared with the valuesobtained from on ASTM E1820⁽¹⁾ and E1457⁽²⁾. Whilst the average values of the contour integral are similar to the ASTM J and C^* values there is significant differences in J and C ^* for the individual crack tip values. This need to be further evaluated in future work.</p>

Topics

• impedance spectroscopy
• polymer
• crack
• creep