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本文利用FPM(Fracture Profile Method)法,测量了40CrNiMoA钢在不同应力状态下发生延性破坏时断裂表面的分形维数,并考察了断面分形维数与断裂应变的关系。结果表明,尽管当应力三维度R_σ从0.86增大至1.52时,断裂应变ε_f自0.37降至0.15,而断面分维D_F仍保持常值(变化幅度仅为1.3％)。估计这是由于具有不同应力三维度的试样其临界空穴扩张比V_(GC)值基本保持常值的缘故。
In this paper, Fracture Profile Method (FPM) was used to measure the fracture surface fractal dimension of 40CrNiMoA steel during ductile failure under different stress conditions. The fractal dimension and fracture strain were also investigated. The results show that although the fracture strain ε_f decreases from 0.37 to 0.15 when the three-dimensional stress R_σ increases from 0.86 to 1.52, the fractal dimension D_F maintains a constant value (with a variation of only 1.3%). It is estimated that this is due to the fact that the critical cavity expansion of the specimens with different three-dimensional stress levels is substantially constant compared to the value of V_ (GC).