Low cycle constant amplitude fully reversed strain controlled testing of low carbon and stainless sheet steels for simulation of straightening operations

Ten sheet steel grades have been tested in fully reversed constant strain a mplitude loading. Seven low carbon steels with proof stresses from 240 MPa to 1500 MPa were included together with one austenitic stainless steel and two duplex stainless steels. For each steel grade, tests at three different strain levels have been performed and hysteresis loops were recorded durin g twenty subsequent cycles. The development of cyclic hardening and softeni ng was illustrated both as a function of strain amplitude and as a function of cycle number. Different constitutive models were evaluated to describe the cyclic flow data. It was found that the best fit was obtained with a co nstitutive model of the type sigma(a)=sigma(0)-C.e(-k.epsilon pl,a)+sigma(x ). sigma(a) and epsilon(pl,a) are stress amplitude and plastic strain ampli tude respectively in the hysteresis loops. sigma(0), C and k are material c onstants. The variable sigma(x) is a function of imposed strain amplitude a nd cycle number. (C) 2000 Elsevier Science Ltd. All rights reserved.