作　　者： ; ; ; ; ; ; ; ;

机构地区： 南京大学电子科学与工程学院近代声学教育部重点实验室

出　　处： 《南京大学学报（自然科学版）》 2003年第4期547-552,共6页

摘　　要： 在超声技术和红外热像技术的基础上,建立了混合型的超声红外热像系统,并利用超声红外热像技术检测材料(试样)的缺陷(裂纹)和残余应力等不均匀结构。当超声波脉冲发射到样品中时,声能在样品中衰减而转化为热能,样品内部及表面的温度会升高。一般情况下,在缺陷或不均匀的区域声衰减更显著,引起的温度变化更大,而温度的差别可以用红外热像仪来观察和记录。因此可以很灵敏和迅速地对缺陷或结构和应力不均匀的区域进行检测。 Conventional nondestructive evaluation (NDE) techniques use various excitation sources, such as ultrasonic waves, X-rays, magnetic powders, eddy currents, etc. to inject into the inspected samples and then characterize the detected results. Since the past decade, an optical energy has been used as another input energy and it induces the temperature increase around the heating area of the sample. If there are defects or inhomogeneous structures inside the sample, the locally inhomogeneous thermal properties or subsurface defects can be displayed by additional temperature rise. The relevant temperature difference on the surface can be observed and recorded by an infrared camera, called infrared thermography for NDE. The advantage of this technique is that it can diagnose defects remotely and safely. However, the infrared thermography for NDE usually suffers from low sensitivity or long imaging time by using simple pulse detection or lock-in technigue respectively. In this paper, a newly developed ultrasonic infrared thermography combined infrared thermography with ultrasonics is described. When a short ultrasonic pulse is excited and infused into a sample, the temperature will increase on the surface of the sample due to the ultrasonic attenuation. If the sample has surface or subsurface defects, the rise of temperature is more apparent on the local surface of the defects than in other areas. The extra heating results from friction or other extra attenuation processes in the vicinities of the defects, so these areas are more heated by the ultrasound selectively. The additional thermal rise can be observed and recorded by the infrared camera. In this way, the defects or inhomogeneous areas can be inspected sensitively and rapidly.

关 键 词： 超声红外热像系统 超声检测 无损检测 无损评价 疲劳裂纹 冲击损伤

领　　域： [理学] [理学] [一般工业技术] [电子电信]