DUCTILE FRACTURE LOCUS VALIDATION METHOD OF THIN STEEL PLATES CONSIDERING THE LODE ANGLE PARAMETER

It was observed that shear fracture dominates in the fracture of steel beam webs. For this reason, the lode angle parameter should be taken into account along with the stress triaxiality. A new ductile fracture calibration method applicable to thin steel plates is proposed in this paper. Five groups of specimens were designed in this paper. They are flat plates, holed flat plates, flat grooved plates, 90° shear plates and 45° shear plates. The true stress-ture strain (σ-ε) curves were obtained through flat plate, halted flat plate specimens and relevant finite element (FE) method iterations. The FE models of other specimens were computed with this σ-ε relationship and compared with related experimental results to obtain the corresponding equivalent fracture strain, average stress triaxiality and average lode angle parameter. With the help of the Matlab Optimization Toolbox, the optimal parameters of the fracture model can be determined.