载荷激励下预制裂纹位向与磁记忆信号的相关性

基于三维磁敏传感器，通过逐级加载方式研究了FV520B钢件在不同轴向载荷激励下预制裂纹位向与三 维磁记忆信号之间的关系，探讨了不同位向裂纹磁记忆信号的特征参量与轴向应力之间的相关性.结果表明： 轴向应力使试件产生自发磁化，磁化强度随载荷的增加而增大,磁记忆切向分量特征参量Bxave和法向分量特征 参量KBz与轴向应力之间具有线性相关关系；三维磁记忆信号(Bx，By，Bz)对不同位向裂纹的检测灵敏度不同， 垂直于三维磁敏探头扫查方向的裂纹漏磁异变特征信号最为强烈，而平行于扫查方向的裂纹无异变特征信号, 可以根据三维磁记忆信号变化特征对裂纹进行准确定位；三维磁记忆信号在断裂后均发生激变，可以根据磁 记忆特征参量ΔBx 和|KG|与轴向应力和残余变形间存在的相关关系评估试件的损伤状态.
Byusingthethree-dimensional(3D)magneticsensordevice,westudiedandresearchedtherelationshipbe? tweentheartificialcracksandthethree-dimensionalmagneticmemorysignalsofFV520Bsteelunderdifferentaxial loadwiththestep-by-steploadingmethod.Thecorrelationbetweensignalcharacteristicparametersofdifferentcrackdi? rectionsandaxialstresswasalsoexplored.Theresultsindicatedthattheaxialstresscausedthespontaneousmagnetiza? tionofthespecimen,andthemagnetizationstrengthenedwiththeincreaseoftheload.Alinearcorrelationbetweenthe tangentialcomponentcharacteristicparameterBxaveandthenormalcomponentcharacteristicparameter KBzandtheaxi? alstresswasfound.However,thethree-dimensionalmagneticmemorysignals(Bx, By, Bz)showeddifferentdetection sensitivitytodifferentcrackdirections.Themagneticmemorysignalsweremostsensitivetothecrackverticaltothe scanningdirectionbutwereinsensitivetothecrackintheparallelscanningdirection,andthecrackcanbeaccurately positionedaccordingtothethree-dimensionalmagneticmemorysignals.Three-dimensionalmagneticmemorysignals changedgreatlyafterfracture,andthedamagestateofthespecimens canbeevaluatedaccordingtothecorrelationbe? tweenthecharacteristicparametersofmagneticmemorysuchasΔBxand|KG|andtheaxialstressaswellastheresidu? aldeformation.