Modelling thermo-mechanical cyclic behavior of P91 steel

Energy Dissipated in Fatigue and Creep Conditions

“…In [ 16 ] the above formula was used as the basic relation for summing the fatigue damage in terms of the plastic strain energy, while in papers [ 18 , 19 ]—for the analysis of the low-cycle fatigue tests results obtained under various load conditions. The energy-based description can also be used when analyzing the results of tests performed under the conditions of load programs including a sequence of constant (creep) and variable (fatigue) loads.…”

“…They have been discussed extensively, for example in [ 7 ]. A linear model refers directly to the proposal described in [ 18 ]. According to this approach, after the implementation of periods of cyclic loading consisting of cycles, and periods of creep loading lasting time , total damage level will be the sum of damage caused by the cyclic load, , and creep, : where is the number of cycles to failure under fatigue conditions only ( and ), while stands for the time to crack occurrence in the creep test only ( , ).…”

Experimental and numerical modeling approach for thermomechanical low cycle fatigue analysis of cyclically non-stabilized steels

“…All the equations of the constitutive model were included in the main article [4] and will not be repeated here. Instead, we present below some technical aspects of the experimental and numerical procedures which were applied to the analysis of the low cycle fatigue of P91 steel, which belongs to the class of non-stabilizing materials.…”

“…The implementation of fatigue tests necessary for the research described in the original paper [4] required the development of an induction heater control system and its synchronization with the testing program of a testing machine. Fig.…”

“…3 ) additionally allows the research to be carried out under conditions σ a =const, and Δ W pl =const. For the materials that do not exhibit a stabilization of cyclic properties, a particularly significant and important parameter is the energy, Δ W pl [4] . Low-cycle tests under the conditions of controlled plastic deformation energy Δ W pl are presented, among others, in the paper [8] .…”