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超声红外热像技术是一种新型无损检测技术,裂纹生热效果直接决定了裂纹的可检测性,而激励源位置是影响裂纹生热的因素之一。针对激励源位置对裂纹生热影响不清楚的问题,建立了超声换能器与被测金属平板的有限元模型,并搭建了超声红外热像检测系统;研究了不同激励源位置时裂纹的生热特性;并利用等效摩擦力、等效速度以及等效热流进行了有效验证。研究表明:当激励源位于裂纹面正下方时,由于裂纹面两侧振动同步,裂纹生热效果将受到抑制;而随着激励源位置向两侧移动,裂纹生热呈现出先波动上升后波动下降的趋势,而且预紧力越大波动越剧烈。研究成果有效地揭示了激励源位置对裂纹生热的影响规律,为超声红外热像技术的检测优化奠定了理论基础。
Ultrasonic infrared thermal imaging technology is a new nondestructive testing technology, the crack heat generation directly determines the detectability of the crack, and the location of the excitation source is one of the factors that affect the heat generation of the crack. Aiming at the problem that the position of excitation source has no clear effect on the heat generation of crack, a finite element model of ultrasonic transducer and metal plate under test is set up and an ultrasonic infrared thermal imaging detection system is set up. Thermal characteristics; and the use of equivalent friction, equivalent velocity and equivalent heat flow were validated. The results show that when the excitation source is located directly below the crack surface, the heat generation in the crack will be restrained due to the synchronization of the vibration on both sides of the crack surface. When the excitation source moves to both sides, the crack initiation heat fluctuates first and then decreases Trend, and the greater the pre-tightening more volatile. The research results have effectively revealed the influence of excitation source location on the crack heat generation and laid the theoretical foundation for the detection and optimization of ultrasonic infrared thermography.