钢结构对接焊缝隐性损伤的磁记忆检测试验研究

Experimental detection on implicit damage of butt weld of steel structure by magnetic memory testing

通过施加拉伸及弯曲荷载,分析了未焊透缺陷及无缺陷的对接焊缝钢构件的磁记忆信号.发现漏磁场强度与外应力存在一定的对应关系,磁场强度随拉应力的增大而增大,随压应力的增大而减小,在应力集中区磁记忆曲线出现波峰或波谷.进入塑性阶段以后磁记忆曲线产生巨大突变,磁场强度突变时刻可用于判断焊缝试件即将破坏的临界状态,梯度峰值可用于表征未焊透缺陷试件的应力集中程度.

Magnetic memory signal of incomplete penetration defects and those without defects of butt weld steel specimens are analyzed under tensile and bending loads. The results show that there are some correlationship between the normal magnetic field and the stress. Magnetic field intensity strengthen will increase as the tensile stress increase, and decrease as the compressive stress increase. The magnetic memory curve appear peak value or across the area of stress concentration. The curve has an abrupt change when the specimens arrive at the plastic stage, and the magnetic field intensity moment of abruptly change can be used to judge the critical state of specimens. The maximum gradient can be used to reflect the degree of stress concentration of weld incomplete penetration.