单调荷载作用下Q355冷弯薄壁型钢平板和角部材料延性断裂性能研究OA

This paper presents an experimental and numerical investigation on the ductile fracture of Q355 cold-formed thin-walled steel flat and corner materials.A total of 58 coupons were tested under monotonic loading,and representative specimens were selected for metallographic observation.For each coupon,the fracture strain and stress state were obtained using refined finite element simulations.Based on the numerical results,the material parameters of five selected fracture models,including Rice-Tracey type model with two parameters(RT2),Rice-Tracey type model with three parameters(RT3),maximum shear stress(MSS),CrashFEM(CF)and VNISFM models,were calibrated.Subsequently,the best-fitting fracture model was implemented via a Usdfld subroutine to verify its accuracy.The results show that the fracture strain of dog-bone specimens increases with the increase of cold bending degree,while the notched specimens show an opposite trend,and the cold bending degree has little effect on the fracture strain of shear specimens.Among the five fracture models,the RT2 model and CF model cannot properly simulate the fracture behavior as they exclusively consider stress triaxiality,while the RT3 model is able to yield satisfactory predictions for both the flat and corner specimens.