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疲劳断裂是异种材料摩擦焊件常见的失效形式。为减少摩擦焊件突然断裂导致的重大事故,从疲劳能量耗散和微观缺陷演化等角度,对联合应用微红外、声发射和微电阻无损检测技术同步动态监测摩擦焊件临界疲劳损伤的可行性进行了探讨。研究发现,疲劳试验过程中,3种信号可同步采集,互不干扰,互相印证。进入临界断裂阶段后,对于试件的异常和正常疲劳断裂,微电阻与声发射的幅值和能量参数变化规律存在良好的映射关系,它们均可作为预警临界断裂失效的参数。虽然红外热像技术常被用于通过监测试样温度场的变化预测材料疲劳极限,但指数增长式的温度快速上升阶段在临界断裂前未必出现。与单信号监测相比,多物理信息融合健康监测预警的可信度更高,有利于提高摩擦焊件的服役安全性和可靠性。
Fatigue fracture is a common failure mode of friction welding of dissimilar materials. In order to reduce the serious accident caused by the sudden rupture of the friction weldment, the feasibility of simultaneous and dynamic monitoring of the critical fatigue damage of the friction weldment by the combination of micro-infrared, acoustic emission and micro-resistance non-destructive testing technology is studied from the perspective of fatigue energy dissipation and microscopic defect evolution Discussed. The study found that during the fatigue test, three kinds of signals can be collected simultaneously, without disturbing each other, confirming each other. After entering the critical fracture stage, there is a good mapping relationship between the amplitude and the energy parameters of the micro-resistance and acoustic emission for the abnormal and normal fatigue fracture of the specimens, which can be used as the parameters of the early warning critical fracture failure. Although infrared thermography is often used to predict material fatigue limits by monitoring changes in the temperature field of the specimen, it is unlikely that the exponential growth phase of rapid temperature rise will occur prior to critical failure. Compared with single signal monitoring, the reliability of multi-physics information fusion health monitoring and early warning is higher, which is beneficial to improve the service safety and reliability of friction welding parts.