Abstract
Under non-proportional mixed-mode loading conditions at the crack tip, some observations are reported. They are limited to cases of cylindrical specimens under normal force and torsion. The fatigue cracks have been initiated by the same loading for which the crack growth behavior has been studied. The observations are discussed against the background of a variety of influence factors on non-proportional mixed mode growth. Finally, a couple of modeling approaches are listed which are – according to the nature or the problem – not yet developed for providing prediction tools in an engineering environment.
Highlights
The calculation of fatigue crack growth along a predefined path is state of the art, see for example one of the latest guidelines [1]
Some scatter is due to the experimental technique, a portion has its origin in the mixed mode hypothesis because it might not describe the fatigue crack growth behavior perfectly
Based on observations reported in this paper, it can be concluded that fatigue crack growth under non-proportional mixed mode loading is depending on various influence factors, which are interrelated and can hardly be separated for individual investigations
Summary
The calculation of fatigue crack growth along a predefined path is state of the art, see for example one of the latest guidelines [1]. The cyclic crack propagation can be calculated with proportional loading, based on the criterion of local symmetry (KII = 0, KIII = 0), even with developing continuously curved crack surfaces. The analysis of such problems requires the simulation of load-bearing and structural geometry-compatible Mode I crack geometry. At least two load sequences that are acting independently are required to cause significant local non-proportional stress states or - in case of cracked structures - nonproportional mixed-mode loading conditions.
Sign-in/Register to view highlights & summary 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 callDisclaimer: 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.
