Experimental study on hysteretic behavior of Q1100 ultra-high strength steel

In order to study the hysteretic behavior of the ultra-high strength steel (UHSS), cyclic tests on Q1100 UHSS with nominal yield strength equal to 1100 MPa are conducted in the present study. The strength softening, preserved strength, and energy dissipation capacity of Q1100 UHSS are analyzed. The influences of the loading scheme and initial residual strain on the hysteretic behavior of UHSS are investigated. It is found that Q1100 UHSS shows a significant softening behavior under cyclic loading. The strength decrease is relatively rapid at the beginning of the cyclic loading and then tends to stabilize. The decrease of the strength of UHSS with larger residual strain tends to be more slowly. The energy dissipation coefficient of Q1100 UHSS increases with the increase of strain amplitude. The sampling direction has a negligible effect on the hysteretic behavior of Q1100 UHSS. A nonlinear combined hardening constitutive model is calibrated for various cyclic loading schemes by using an automatic calibration method and the cyclic behavior of Q1100 UHSS is predicted well.