Issue 38

S. Suman et alii, Frattura ed Integrità Strutturale, 38 (2016) 224-230; DOI: 10.3221/IGF-ESIS.38.30 229 from the thesis of Morrow [18], is shown in Fig. 4(b). This data set includes uniaxial, torsional, proportional and non- proportional multiaxial data from an IN 718 alloy. It can be seen that the new parameter also collapses this data set extremely well to a single curve, providing further evidence of its ability to predict fatigue lives in a variety of materials and load paths. (a) (b) Figure 4 : Proposed damage parameter applied to (a) Ti-6Al-4V and (b) IN 718 [18]. C ONCLUSION new critical-plane damage parameter for the prediction of fatigue life under multiaxial loading has been presented. This new parameter has been evaluated using a significant amount of fatigue data from several high strength titanium and steel alloys, and found to provide excellent correlation of the data. The parameter can account for strain hardening in the LCF regime, and the effect of mean stresses in the HCF regime. The parameter is computationally inexpensive and requires determination of only two material constants. R EFERENCES [1] Gough, H.J., Polland, H.V., Clenshaw, W.J., Some experiment on the resistance of metals under combined stress, Aeronautical Research Council Report and Memoranda No. 2522, HMSO, London, (1951). [2] Stulen, F.B., Cummings H.N., A failure criterion for multiaxial fatigue stresses, Proc. of ASTM, 54 (1954) 822-830. [3] Sines, G., Waisman, J.L., Metal Fatigue, McGraw-Hill, New York, (1959). [4] Stephens, R.I., Fatemi, A., Stephens, R.R., Fuchs, H.O., Metal Fatigue in Engineering, second ed., John Wiley & Sons, New York, (2001). [5] Garud, Y.S., A new approach to the evaluation of fatigue under multiaxial loadings, J. Eng. Mater. Technol., 103 (1981) 118-125. [6] Ellyin, F., Valaire, B., High-Strain Multiaxial Fatigue, J. Eng. Mater. Technol. 104 (1982) 165-173. [7] Glinka, G., Wang, G., Plumtree, A., Mean stress effect in multiaxial fatigue, Fatigue Fract. Eng. Mater. Struct., 18 (1995) 755-764. [8] Farahani, A.V., A new energy-critical plane parameter for fatigue life assessment of various metallic materials subjected to in-phase and out-of-phase multiaxial fatigue loading conditions, Int. J. Fat., 22 (2000) 295-305. [9] Pan, W.F., Hung, C.Y., and Chen, L.L., Fatigue life estimation under multiaxial loading, Int. J. Fat., 21 (1999) 3-10. [10] Findley, W.N., A theory for the effect of mean stress on fatigue of metals under combined torsion and axial load or Bending, J. Eng. Ind., (1959) 301-306. [11] Findley, W.N., Effect of range of stress on fatigue of 76S-T61 aluminum alloy under combined stresses which produce yielding, J. Appl. Mech., (1953) 365-374. [12] McDiarmid, D.L., A general criterion for high cycle multiaxial fatigue failure, J. Fat. Fract. Eng. Mater. Struct., 14 (1991) 429-453. [13] Matake, T., Explanation of fatigue limit under combined stress, Bulletin of the JSME, 20 (1977) 257-264. A