不同角度含裂纹损伤钢构件拉伸试验与分析

Tensile Test and Analysis of Steel Members with Crack Damage at Different Angles

针对含裂纹损伤钢构件呈现脆性现象的问题,大多数研究者均假设裂纹与受力方向垂直,且假设屈强比不会随裂纹的变化而变化。然而,实际工程中裂纹出现的角度是随机的,且含裂纹损伤钢构件的屈强比会随着裂纹长度发生改变。针对Q235和Q355两种不同钢材,对不同角度的含裂纹损伤钢构件进行试验和分析研究。考虑不同裂纹角度下,且屈强比变化的情况下,研究含裂纹损伤钢构件呈现脆性现象的情况。结果表明:计算屈服强度时,任意裂纹角度均可以投影成与受力方向垂直的裂纹处理。当相对裂纹长度一定时,屈强比越大,含裂纹损伤钢构件越容易呈现脆性性能。当相对裂纹长度增大时,含裂纹损伤钢构件的屈强比增大,采用变化的屈强比,改进了剩余极限强度公式,使公式计算值与试验值误差小于1%。研究成果对含裂纹损伤钢构件后期的预防、修复和加固具有一定的理论价值和现实意义。

Aiming at the problem of brittleness of steel members with crack damage. Most researchers assume that the crack is perpendicular to the stress direction, and assume that the yield ratio will not change with the change of the crack. However, the angle of cracking in actual engineering is random, and the flexural strength ratio of crack-damaged steel members is changed with the crack length. For two different steels, Q235 and Q355, the experimental and analytical research of the damaged steel members with cracks from different angles were carried out. The brittleness of crack-damaged steel members was investigated by considering different crack angles with varying flexural strength ratios. The results show that when the yield strength is calculated, any crack angle can be projected into a crack treatment perpendicular to the force direction. When the relative crack length is certain, the larger the yield strength ratio is, the more likely the cracked steel member presents brittle properties. When the relative crack length increases, the flexural strength ratio of the crack-damaged steel member increases, and the residual ultimate strength formula is improved by using a variable flexural strength ratio, so that the error between the formula calculated value and the test value is less than 1%. The research results have certain theoretical value and practical significance for the prevention, repair and strengthening of cracked steel members in the later stage.