Volume 12, Issue 3, August 2015, Pages 676–684
Kévin M. Tsapi Tchoupou1 and Bertin D. Soh Fotsing2
1 Department of Petroleum Engineering, National Higher Polytechnic Institute, University of Bamenda, P.O. Box 39 Bambili, Cameroon
2 Department of Mechanical Engineering, Bandjoun University Institute of Technology, University of Dschang, P.O. Box 134 Bandjoun, Cameroon
Original language: English
Copyright © 2015 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Newer fatigue prediction models for estimating the multiaxial fatigue limit often lack a simple analytical solution and the complexity of multiaxial solutions during programming makes testing an unattractive task. This paper summarizes an attempt to propose a novel equivalent stress approach suitable for estimating fatigue damage in the presence of complex multiaxial fatigue loadings. According to the devised method, fatigue limit under multiaxial loading is evaluated by proposing an equivalent loading with zero out-of-phase angles. The accuracy of the proposed approach was systematically checked by means of 87 experimental data taken from the literature and generated by testing different metallic materials under both in-phase and out-of-phase biaxial fatigue loading. Results show that the equivalent stress approach is an elaboration of non-conservative stress invariant based multiaxial fatigue criteria like the well-known Sines method. This exercise allowed us to prove that the systematic application of the equivalent stress resulted in highly accurate predictions and it held true independently of the cause of the mobility of principal stress directions of the stress field damaging the fatigue process zone. Simulations also emphasize a general quite better precision of the proposed equivalent stress approach when compared to another method, namely the minimum circumscribed ellipse approach.
Author Keywords: multiaxial fatigue, stress invariant, non-proportional loading, proportional loading, constant amplitude.
Kévin M. Tsapi Tchoupou1 and Bertin D. Soh Fotsing2
1 Department of Petroleum Engineering, National Higher Polytechnic Institute, University of Bamenda, P.O. Box 39 Bambili, Cameroon
2 Department of Mechanical Engineering, Bandjoun University Institute of Technology, University of Dschang, P.O. Box 134 Bandjoun, Cameroon
Original language: English
Copyright © 2015 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Newer fatigue prediction models for estimating the multiaxial fatigue limit often lack a simple analytical solution and the complexity of multiaxial solutions during programming makes testing an unattractive task. This paper summarizes an attempt to propose a novel equivalent stress approach suitable for estimating fatigue damage in the presence of complex multiaxial fatigue loadings. According to the devised method, fatigue limit under multiaxial loading is evaluated by proposing an equivalent loading with zero out-of-phase angles. The accuracy of the proposed approach was systematically checked by means of 87 experimental data taken from the literature and generated by testing different metallic materials under both in-phase and out-of-phase biaxial fatigue loading. Results show that the equivalent stress approach is an elaboration of non-conservative stress invariant based multiaxial fatigue criteria like the well-known Sines method. This exercise allowed us to prove that the systematic application of the equivalent stress resulted in highly accurate predictions and it held true independently of the cause of the mobility of principal stress directions of the stress field damaging the fatigue process zone. Simulations also emphasize a general quite better precision of the proposed equivalent stress approach when compared to another method, namely the minimum circumscribed ellipse approach.
Author Keywords: multiaxial fatigue, stress invariant, non-proportional loading, proportional loading, constant amplitude.
How to Cite this Article
Kévin M. Tsapi Tchoupou and Bertin D. Soh Fotsing, “A new high cycle fatigue equivalent stress applied to out-of-phase biaxial stress state,” International Journal of Innovation and Applied Studies, vol. 12, no. 3, pp. 676–684, August 2015.
