Low‐cycle fatigue of 316L stainless steel under proportional and nonproportional loadings

Abstract

This paper discusses low‐cycle fatigue characteristics of 316L stainless steel under proportional and nonproportional loadings. Tension–torsion multiaxial low‐cycle fatigue tests were performed using five strain paths. Additional hardening was observed under nonproportional loadings and was more significant in tests with larger nonproportionality. Mises equivalent strain, Smith–Watson–Topper, Fatemi–Socie, Kandil–Brown–Miller and nonproportional strain parameters were applied to the experimental data to evaluate the multiaxial low‐cycle fatigue damage. The applicability of the damage laws to practical design was discussed.

Investigation of the multiaxial fatigue behaviour of 316 stainless steel based on critical plane method

“…The small effect of the mean stress is confirmed with the good predictions obtained with FS with very small values of the k parameter that takes into account the mean stress effect. Moreover, this fact is confirmed by the good agreement with previous works that employed FS and WB models without mean stress effect . The failure plane was also assessed with the critical plane models.…”

“…For such cases, a new version of WB could be proposed that takes into account only the strains on the outer surface. Such version would be very appropriate for types of loading similar to these studied here and appear to be ideal for full‐field experimental techniques such as Moiré interferometry, electronic speckle pattern interferometry, or digital image correlation that measure a detailed displacement field across the surface …”

“…Such version would be very appropriate for types of loading similar to these studied here and appear to be ideal for full-field experimental techniques such as Moiré interferometry, 53 electronic speckle pattern interferometry, 54 or digital image correlation 55 that measure a detailed displacement field across the surface. 19 Comparison between tests 2 and 6A is useful to understand the sensitivity of the material to the different types of load. Both test 2 and test 6A are subjected to the same inner pressure.…”

“…New creep models for 316L were developed and extended to creep‐fatigue to estimate fatigue life; however, very conservative results were returned . The multiaxial behaviour of 316L stainless steel was also investigated with different critical plane models under strain control . Both proportional and nonproportional loading conditions were studied with different combinations of tension, compression, and torsion.…”

Multiaxial low‐cycle fatigue life evaluation under different non‐proportional loading paths

“…The critical plane approach is developed based on the initiation and accumulation of fatigue damage on a certain critical plane and considers that the cumulative fatigue damage occurs on the certain critical plane . The critical plane approach has been shown to be effective and widely used in multiaxial fatigue assessment extensively by a number of researchers …”