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建立不同补强钢板厚度、宽度的分析模型,绘制焊根、焊趾应力分布曲线,分析不同补强钢板尺寸对裂纹尖端应力的影响。在此基础上,对比钢板补强试件模型(补强钢板厚度、宽度分别为10,300 mm)的开裂试件模型、未开裂试件模型的焊根应力分布情况,并结合相同几何参数的钢板补强试件的疲劳试验结果,从裂纹尖端应力变化、裂纹扩展速率、疲劳寿命等角度,对钢板补强维护效果进行评价。研究结果表明:裂纹尖端应力受补强钢板厚度影响较小,考虑到常见的顶板厚度与U肋厚度,在实际应用中可取补强钢板厚度为10 mm;补强钢板边缘对应的焊根、焊趾位置无应力突变现象;补强钢板宽度为3倍裂纹长度时,裂纹尖端应力下降约18%;在焊趾设置补强钢板可明显提升裂纹扩展寿命,与有限元分析结果一致。
The analysis model of the thickness and width of reinforcing steel plates is established. The stress distribution curve of welding root and weld toe is plotted, and the influence of different reinforcing steel plates on the crack tip stress is analyzed. On this basis, the stress distribution of welded root of uncracked specimens was compared with that of steel reinforced specimens (reinforced steel thickness and width of 10,300 mm, respectively) and steel plates with the same geometric parameters The results of the fatigue test of the strong specimens show that the reinforcement effect of the steel plate is evaluated from the stress changes of the crack tip, the crack growth rate and the fatigue life. The results show that the crack tip stress is less affected by the thickness of reinforcing steel plate. Considering the common roof thickness and U-rib thickness, the thickness of reinforcing steel plate is 10 mm in practical application. The phenomenon of no-stress abrupt change at the toe position; when the width of the reinforcing steel plate is 3 times the crack length, the stress at the tip of the crack is reduced by about 18%; setting the reinforcing steel plate at the weld toe can obviously improve the crack propagation life, consistent with the finite element analysis.