立式钢制储罐大角焊缝处裂纹的应力强度因子分析

Stress Intensity Factor Analysis of Cracks in Shell-to-Bottom Weld of Vertical Steel Storage Tank

为了研究大角焊缝处裂纹的断裂性能,建立了大角焊缝处含Ⅰ型裂纹的100 000m^3立式钢制储罐有限元简化模型,并基于断裂力学理论分析了裂纹最深处的应力强度因子K_I值及其与主要影响参数的关系。基于分析结果,根据裂纹的位置将大角焊缝附近的裂纹分为底板裂纹、焊缝裂纹和焊趾裂纹,并分别拟合了3类裂纹的K_I值计算公式,据此可以根据现场实际检测的裂纹尺寸和裂纹位置简单有效地对此类裂纹的断裂性能进行工程评估。

In order to study the fracture behavior of cracks at shell-to-bottom weld,a simplified finite element model for 100 000 m^3 vertical steel storage tank with Type Ⅰ cracks at large fillet weld was established.Based on fracture mechanics theory,the stress intensity factor K_I at the deepest position of the crack and its relationship with the main influencing parameters were analyzed. Basing on this analysis results,the cracks near the fillet weld were divided into floor cracks,weld cracks and toe cracks according to the location of the cracks and the K_I calculation formulas of the three types of cracks were fitted respectively and then,based on these formulas,the fracture performance of cracks can be evaluated simply and effectively according to the crack size and location detected in the field.