TY - JOUR
T1 - Cyclic yield strength in definition of design limits for fatigue and creep
AU - Gorash, Yevgen
AU - Mackenzie, Donald
PY - 2014/12
Y1 - 2014/12
N2 - This study proposes a cyclic yield strength (CYS, σc ) as a key characteristic for the definition of safe design for engineering structures operating under fatigue and creep conditions. CYS is defined on a cyclic stress-strain curve, while monotonic yield strength (MYS, σm ) is defined on a monotonic stress-strain curve. Both values of σc and σm are identified using a 2-steps fitting procedure of the experimental stress-strain curves using Ramberg-Osgood and Chaboche material models. Comparison of σc and fatigue endurance limit σf on the S-N fatigue curve reveals that they are approximately equal. Hence, basically safe fatigue design is guaranteed in purely elastic domain defined by the σc . A typical creep rupture curve in time-to-failure approach for creep analysis has 2 inflections corresponding to the σc and σm . These stresses separate 3 sections on the creep rupture curve, which are characterised by 3 different creep fracture modes and 3 creep deformation mechanisms. Thus, basically safe creep design is guaranteed in linear creep domain with brittle failure mode defined by the σc . These assumptions are confirmed for several structural low- and high-alloy steels for normal and high-temperature applications.
AB - This study proposes a cyclic yield strength (CYS, σc ) as a key characteristic for the definition of safe design for engineering structures operating under fatigue and creep conditions. CYS is defined on a cyclic stress-strain curve, while monotonic yield strength (MYS, σm ) is defined on a monotonic stress-strain curve. Both values of σc and σm are identified using a 2-steps fitting procedure of the experimental stress-strain curves using Ramberg-Osgood and Chaboche material models. Comparison of σc and fatigue endurance limit σf on the S-N fatigue curve reveals that they are approximately equal. Hence, basically safe fatigue design is guaranteed in purely elastic domain defined by the σc . A typical creep rupture curve in time-to-failure approach for creep analysis has 2 inflections corresponding to the σc and σm . These stresses separate 3 sections on the creep rupture curve, which are characterised by 3 different creep fracture modes and 3 creep deformation mechanisms. Thus, basically safe creep design is guaranteed in linear creep domain with brittle failure mode defined by the σc . These assumptions are confirmed for several structural low- and high-alloy steels for normal and high-temperature applications.
KW - cyclic analysis
KW - design limits
KW - fatigue assessment
KW - creep-fatigue strength
UR - http://onlinelibrary.wiley.com/doi/10.1002/pamm.201410170/pdf
U2 - 10.1002/pamm.201410170
DO - 10.1002/pamm.201410170
M3 - Article
VL - 14
SP - 365
EP - 366
JO - Proceedings in Applied Mathematics and Mechanics, PAMM
JF - Proceedings in Applied Mathematics and Mechanics, PAMM
SN - 1617-7061
IS - 1
T2 - 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics, GAMM 2014
Y2 - 10 March 2014 through 14 March 2014
ER -