Issue 38

T. Inoue et alii, Frattura ed Integrità Strutturale, 38 (2016) 259-265; DOI: 10.3221/IGF-ESIS.38.35 265 10 3 Predicted fatigue life (hour) 10 0 10 1 10 2 10 0 10 1 10 2 10 3 Measured fatigue life (hour) Factor of 3 Factor of 3 Flat type  cr  ma Projection type Conservative Non-conservative Condition A Condition B Figure 6 : Comparison between predicted fatigue lives and measured fatigue lives. C ONCLUSIONS 1. We have developed a planar tri-axial fatigue testing machine which can reproduce arbitrary in-plane stress states by applying three independent loads in the 0, 45, and 90 degree directions. The complex stress data obtained from actual transport machinery in operation has been reproduced with an error range of less than 10%. 2. Predicted fatigue lives using stress calculated by critical plane method were over a factor of 10 against measured fatigue lives under random non-proportional loading conditions. 3. Predicted fatigue lives using stress in consideration of the non-proportional level were within a factor of 3 against measured fatigue lives. R EFERENCES [1] Shamsaei, N., Fatemi, A., Socie, D. F., Multiaxial fatigue evaluation using discriminating strain paths, Int. J. Fatigue, 33 (2011) 597–609. [2] Ahmadzadeh, G.R., Varvani-Farahani, A., Fatigue life assessment of steel samples under various irregular multiaxial loading spectra by means of two energy-based critical plane damage models, Int. J. Fatigue, 84 (2016) 113-121. [3] Liu, X.-Y., Su, T.-X., Zhang, Y., Yuan, M.-N., A multiaxial high-cycle fatigue life evaluation model for notched structural components, 80 (2015) 443-448. [4] Gotoh, K., Niwa, T., Anai, Y., Fatigue crack growth behavior of an out-of-plane gusset welded joints under biaxial tensile loadings with different phases, Procedia Materials Science, 3 (2014) 1536-1541. [5] Susmel, L., Multiaxial Notch Fatigue: from Nominal to Local Stress/Strain Quantities, Woodhead Publishing Limited, Abington Hall, Granta Park, Creat Abington, Cambridge CB21 6AH, UK, (2009).