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为准确预测钢结构构件的断裂破坏,提出了基于裂纹扩展阻力曲线的评估方法。基于前期开展的低温下结构钢材的裂纹尖端张开位移(CTOD)试验结果,采用试验数据回归和理论分析方法,对裂纹扩展阻力曲线的参数进行标定,并分析裂纹扩展阻力曲线形式与含裂纹钢构件断裂模式的关系。结果表明:当构件初始裂纹长度大于临界值且钢材裂纹扩展阻力曲线呈上凸形时,构件发生韧性断裂;当构件初始裂纹长度小于临界值且阻力曲线呈上凸形时,或当阻力曲线呈水平直线时,构件发生脆性断裂。本文理论模型计算的最大载荷点裂纹扩展量与试验实测值吻合较好,验证了理论分析的准确性,可应用于钢结构构件的防断设计。
In order to accurately predict the failure of steel structural members, an evaluation method based on the crack growth resistance curve is proposed. Based on the results of the crack tip open displacement (CTOD) test of structural steel at low temperature, the parameters of the crack propagation resistance curve were calibrated by the experimental data regression and theoretical analysis method, and the relationship between the crack growth resistance curve and the cracked steel Relationship between the fracture modes of the members. The results show that when the initial crack length is larger than the critical value and the crack propagation resistance curve of steel is convex, the member will fracture ductilely. When the initial crack length is smaller than the critical value and the resistance curve is convex, When the horizontal straight line, the component brittle fracture occurs. The theoretical model calculated the maximum load point crack propagation in good agreement with the experimental measurements to verify the accuracy of the theoretical analysis can be applied to the steel components of the anti-off design.