PSI - Issue 13

Yanzeng Wu et al. / Procedia Structural Integrity 13 (2018) 890–895

895

Yanzeng Wu et al. / Structural Integrity Procedia 00 (2018) 000 – 000

6

Table 1. Areas of the CTOD loops corresponding to different locations from the crack tip. Distance from crack tip HAB / μ m 2 non-HAB / μ m 2 10 pix (8.9 μ m) 0.0887 0.142 50 pix (44.7 μ m) 0.0967 0.118 100 pix (89.5 μ m) 0.0955 0.107 Table 2. Values of the CTOD for maximum load corresponding to different locations from the crack tip. Distance from crack tip HAB / μ m non-HAB / μ m 10 pix (8.9 μ m) 1.262 1.685 50 pix (44.7 μ m) 3.003 3.398 100 pix (89.5 μ m) 4.555 5.119

4. Conclusions

An in-situ measurement of the CTOD has been performed to investigate the influence of HAB in LMD TC11. DIC technique has been implemented for measuring the variation of CTOD within a full loading cycle and evaluating the crack opening stress levels in this paper. Major points are summarized below:  Crack closure is observed from the variation of CTOD during the initial loading portion and the crack opening stress level corresponding to HAB is slightly higher than non-HAB, by which it influences the crack growth rate indirectly.  Due to its distinguishing microstructure, the value of CTOD in the HAB zone is smaller than that in non-HAB zone at the same load level when the crack is opening.  Areas of CTOD loops in a full loading cycle are compared between HAB and non-HAB zone, there still exist significant differences between them. The area of CTOD loop is related with the crack opening stress and the maximum value of CTOD, it may be used as a viable parameter to characterise fatigue crack growth.

Acknowledgements

This work was financially supported by the Natural Science Foundation of China (No. 11672012).

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