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采用不同锤高对X90管线钢试样进行落锤撕裂试验,利用GTN微观损伤模型对试验过程进行有限元模拟,详细研究裂纹稳态扩展速度与临界裂尖张开角的关系,并对试验和模拟结果进行分析和对比。结果表明:试样的断裂韧性随稳态断裂速度的增大而减小;有限元计算的断裂速度、裂尖张开角与试验结果吻合较好,GTN微观损伤参数能较好地应用于X90管线钢的动态断裂分析;现有的DWTT方法在评估试样的断裂韧性时存在缺陷,应考虑试样的起裂和冲击变形对评估的影响。
The drop weight tear test was carried out on X90 pipeline steel samples with different hammer heights. The GTN microscopic damage model was used to carry out the finite element simulation of the test process. The relationship between crack steady state propagation speed and critical crack tip opening angle was studied in detail. The experimental and simulation Results were analyzed and compared. The results show that the fracture toughness of the sample decreases with the increase of the steady state fracture rate. The fracture speed and the crack tip open angle calculated by the finite element method are in good agreement with the experimental results. The microscopic damage parameters of GTN can be well applied to the X90 pipeline steel The existing DWTT method has some defects in evaluating the fracture toughness of the specimen. The impact of specimen cracking and impact deformation on the assessment should be considered.