基于休哈特控制图的磁记忆早期损伤检测方法

Magnetic memory detection method for early damage based on Shewhart control chart

为完善金属磁记忆检测早期损伤的定性定量评价方法,开展Q235钢圆棒试件扭转试验。利用应力集中磁指示仪,记录不同扭矩作用下的试件表面的磁记忆信号的切向分量Hx和法向分量Hy。进而提出基于休哈特控制图的磁记忆信号早期损伤检测方法。结果表明,磁信号在试件屈服时发生明显跳变,此时合成磁场梯度绝对值正好达到最大;借助休哈特控制图,能消除梯度值波动对信号判断的干扰,并能给出试件产生屈服时的准确异常预警范围,从而较好地实现磁记忆早期损伤的快速准确识别。

In order to perfect the qualitative and quantitative methods for evaluating metal early damage using magnetic memory technique,torsion tests of circular specimens made of Q235 steel were conducted.The tangential component Hxand normal component Hyof magnetic memory signals under different torques were recorded by a stress concentration indicator. An early damage diagnosis approach via magnetic memory signals based on Shewhart control chart was developed. The results show that the magnetic signal produces an sharp change when the specimen is yielding, corresponding to the maximum synthetic magnetic field gradient value,and that having the aid of the Shewhart control chart the interference of fluctuating gradients in the judgement can be eliminated abnormal warning ranges can be indicated accurately when yielding,and quick and accurate identification of early damage.