球墨铸铁管道磁记忆应力检测的数值模拟及验证研究

Numerical Simulation and Verification of Magnetic Memory Stress Detection in Ductile Iron Pipeline

目的针对当前磁记忆应力检测方法研究较少的问题,建立适用于球墨铸铁管道的磁记忆应力检测方法,并进行合理验证。方法采用解析计算和有限元仿真模拟2种方法,建立球墨铸铁管道磁记忆应力检测模型,研究应力值和传感器提离值对球墨铸铁管道磁记忆信号的影响,并通过搭建球墨铸铁管道磁记忆应力检测实验平台进行模型验证。结果轴向峰值和径向零点位置不随应力变化发生偏移,信号强度随应力值增加呈线性变化。球墨铸铁管道磁记忆信号随着提离值的增加呈指数衰减,在2.5~4 mm内,提离值的衰减近似呈线性,信号波动较小,适用于信号采集。结论2种方法的结果较为吻合,球墨铸铁管道磁记忆应力检测实验平台的结果与数学仿真计算具有很好的一致性,这些模拟和实验结果均验证了基于解析计算和有限元建立的2种磁记忆应力检测模型的数值合理性。

Aiming at the lack of study on magnetic memory stress testing method,the work aims to develop a new method for ductile iron pipelines and verify its reasonableness.Based on analytical calculations and finite element simulation,a magnetic memory stress testing model for ductile iron pipelines was developed.The influence of stress values and sensor lift-off on the magnetic memory signal of the ductile iron pipelines was studied,and the model was verified by constructing an experimental platform for magnetic memory stress testing of ductile iron pipelines.The results indicated that the axial peak and the radial zero-point positions did not shift with stress change,while the signal strength varied linearly with the increase of stress.The magnetic memory signal of the ductile iron pipelines exponentially decayed with the increase in lift-off.Within the range of 2.5 to 4 mm,the decay was approximately linear with minimal signal fluctuation,which was suitable for signal acquisition.The results from both methods are in good agreement.The outcomes from the magnetic memory stress testing experimental platform align well with the mathematical simulation calculations,validating the numerical rationality of the two magnetic memory stress testing models established based on analytical calculations and finite element simulation.