A Probabilistic Two-Scale Approach to Predict the High Cycle Fatigue Behaviour of Ti-Al6-V4 Parts Machined by High Pressure Water Jet Assisted Turning

Abstract:

The high cycle fatigue life of machined parts is affected by the so-called surface integrity induced by the machining process. To model the high cycle fatigue behaviour of turned parts a probabilistic two-scale continuum damage model is developed. While the macroscopic behaviour of the material is assumed to remain elastic during the fatigue loading, the fatigue prediction is based on the incremental evolution of micro-plasticity and damage. The non-standard initial mechanical state of the material in the sub-surface, viz. the plastic strains and residual stresses fields induced by the machining process are taken into account via an initial step prior to the fatigue loading. As far as the micro-geometry of the surface is concerned, an initial micro-crack distribution depending on the depth and shape of the micro-defects observed is introduced.

• Periodical: Advanced Materials Research (Volumes 891-892)
• Pages: 791-796
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.891-892.791
• Online since: March 2014
• Authors: Pierre Mella*, René Billardon, Rodrigue Desmorat
• Keywords: Damage, HCF, Machining, Residual Stress, Surface Integrity, TA6V

References

[1] J. Lemaitre, I. Doghri, Damage 90: a post processor for crack initiation, Computer Methods in Applied Mechanics and Engineering, Vol. 115, Issues 3-4, (1994), pp.197-232.

DOI: 10.1016/0045-7825(94)90060-4

[2] Kröner E., On the plastic deformation of polycristals, Acta Metallurgica, 9, (1961), pp.155-161.

[3] Barbier G., Fatigue biaxiale à grand nombre de cycles : étude expérimentale et modèle d'endommagement à deux échelles probabiliste, Phd Thesis, ENS Cachan, (2009).

[4] Berveiller M., Zaoui A., An extension of the self-consistent scheme to plastically-flowing polycristals, Journal of the Mechanics and Physics of Solids, 26, 5-6, (1978), pp.325-344.

DOI: 10.1016/0022-5096(78)90003-0

[5] M. Suraratchai, J. Limido, C. Mabru, R. Chieragatti, Modelling the influence of machined surface roughness on the fatigue life of aluminium alloy, International Journal of Fatigue, Vol. 30, Issue 12, (2008), pp.2119-2126.

DOI: 10.1016/j.ijfatigue.2008.06.003

[6] A. Souto-Lebel, N. Guillemot, C. Lartigue, R. Billardon, Characterization and influence of defect size distribution induced by ball-end finishing milling on fatigue life, Procedia Engineering, Vol. 19, (2011), pp.343-348.

DOI: 10.1016/j.proeng.2011.11.123

[7] R. Jones, S. Barter, F. Chen, Experimental studies into short crack growth, Engineering Failure Analysis, Vol. 18, Issue 7, (2011), pp.1711-1722.

DOI: 10.1016/j.engfailanal.2011.03.012