基于热-磁特征融合的再制造构件疲劳微损伤评估研究

The effective assessment of the micro-damage in remanufacturing blank is related to the safety of remanufacturing products, which has significant effect on improving the overall performance of remanufacturing parts. This project aims at the practical problem that it is difficult to achieve the micro-damage quantitative assessment by single characteristic detection: the basic theory innovation is carried out from the perspective of thermal - magnetic characteristics fusion, remanufacturing components and their materials are selected to carry out the research of thermal-magnetic fusion detection principle and assessment mechanism for fatigue micro-damage. Polarization detection is employed on the basis of infrared thermal image, and the collection and characterization of thermal and magnetic signals during fatigue process are realized by magnetic domain observation and three-dimensional magnetic signal detection. The thermal dissipation and magnetic domain wall displacement under the action of stress/imposed magnetic field during damage process are calibrated form thermal and magnetic aspects, and the thermal-magnetic characteristics inversion for remanufacturing components fatigue micro-damage process can be achieved. The three-dimensional surface morphological mapping model of fatigue damage process is established. Taking three-dimensional roughness which represents the morphology change as the medium, the damage association law between thermal infrared spontaneous radiation polarization characteristics and magnetic domain wall displacement characteristics is revealed, and the characteristic function of thermal-magnetic fusion in the process of fatigue micro-damage is described. Finally, a thermal-magnetic fusion assessment model of fatigue micro-damage is built and a remanufacturing component is selected as an example to demonstrate the model. The research can provide theoretical support for residual life prediction of various ferromagnetic components and assessment of their remanufacturing performances.

再制造毛坯疲劳微损伤的有效评估关系到再制造产品的服役安全，对提高再制造件整体性能意义重大。项目针对单一特征检测难以实现疲劳微损伤量化评估的现实问题，从热-磁特征融合的角度进行基础理论创新，选取再制造构件及其材料开展疲劳微损伤的热-磁融合检测机理及评估机制研究。在红外热像基础上引入偏振探测，并通过磁畴观测和三维磁信号检测，实现疲劳过程的热、磁信号采集及表征；进行损伤过程热耗散和应力/外加磁场作用下磁畴畴壁位移量化标定，实现再制造构件疲劳微损伤的热、磁特征反演；建立疲劳微损伤过程三维表面形貌映射模型，以表征形貌变化的三维粗糙度为媒介，揭示热红外自发辐射偏振特性及磁畴畴壁位移特性之间的损伤关联规律，进行疲劳微损伤过程热-磁融合特征的函数描述；最后建立疲劳微损伤热-磁融合评估模型并选取典型再制造构件进行方法验证。项目研究成果能够为各类铁磁构件剩余寿命预测及再制造性评价提供理论支撑和方法保障。

项目选取铁磁材料试样开展了疲劳微损伤热-磁特征融合评估研究。获取了损伤过程热红外自发辐射偏振图像及地磁场/外加磁场环境下的试样表面磁信号，提取了热力学熵、偏振度等热特征参数及磁信号梯度、多尺度熵等磁特征参数。采集了疲劳损伤过程三维表面形貌特征参数，结合表面高度分布和多重分形理论，进行了表面粗糙度三维评定，构建了疲劳损伤过程三维表面形貌映射模型。揭示了热红外自发辐射偏振特性及磁畴畴壁位移特性之间的损伤关联规律，结合热力学熵、偏振度等特征以及磁信号强度及梯度、磁信号多尺度熵等特征，进行了疲劳损伤过程的热、磁特征反演。构造了疲劳微损伤的热、磁特征非线性映射，基于联合熵等方法建立了疲劳微损伤热-磁融合评估模型。项目成果可为再制造铁磁构件剩余寿命预测及再制造性评价提供理论方法支撑。