Ductile damage model calibration for high-strength structural steels

Numerical analyses incorporating appropriate damage models provide an opportunity to predict the strength and deformation capacity of steel structures. This paper presents a practical calibration for the ductile damage model of 5355 and high-strength steel S690Q S700MC, S960Q based on tensile coupon test results. A combined linear and power expression is adopted to calibrate the post-necking damaged stress-strain relations of the investigated steels, upon which the undamaged stress-strain relations are estimated further. Damage initiation criterion is based on the Rice-Tracey model and damage evolution law is related to the calibrated damaged stress and the estimated undamaged stress. Fracture of the tensile coupons is modelled using a critical damage variable. Tensile coupon tests on the investigated steels are modelled in ABAQUS with the explicit solver. Results show that combining the proposed post-necking stress-strain relations and ductile damage model generates very good predictions for strain localization and final fracture of the tensile coupons. Numerical engineering stress-strain curves agree well with the experimental results. It also indicates that high-strength steels are more susceptible to damage than 5355. The damage variable of S960Q is about 2 times as large as that of 5355 from the onset of necking to the final fracture. (C) 2020 Elsevier Ltd. All rights reserved.