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近年来,脉冲红外成像无损评估方法已成功应用于航空航天、汽车制造、新材料等领域。但是对于很多应用,仅发现材料中存在缺陷是不够的,还需要对表面下缺陷热特性进行识别。实验设计制作了一个不锈钢平底孔试件,为了模拟表面下不同性质的暗藏物,在平底孔内分别埋入水、油、石蜡及空气。在试件表面施加均匀脉冲面热源后,试件表面及表面下暗藏物的热物理特性将影响热波的传导。提出了一种使用脉冲红外成像技术测量均匀固体材料下暗藏物质蓄热系数的实验方法。描述并分析了基于两层结构的一维热传导模型和界面热反射系数的计算方法,设计并进行了验证实验,通过对实验获得的材料表面温度变化的热图序列进行处理和分析,计算得到试件中不同暗藏物质的蓄热系数。
In recent years, the nondestructive evaluation method of pulsed infrared imaging has been successfully applied in the fields of aerospace, automobile manufacturing, new materials and so on. However, for many applications, it is not enough to find defects in the material alone, and the thermal characteristics of sub-surface defects need to be identified. Experimental Design A stainless steel flat-bottomed hole specimen was prepared. In order to simulate the hidden objects with different properties under the surface, water, oil, paraffin and air were respectively embedded in the flat-bottom holes. After the uniform pulse surface heat source is applied on the surface of the specimen, the thermophysical properties of the hidden objects on the surface and subsurface of the specimen will affect the conduction of the thermal wave. An experimental method for measuring the heat storage coefficient of hidden material under uniform solid material using pulsed infrared imaging technology is proposed. A one-dimensional heat conduction model based on two-layer structure and calculation method of thermal reflection coefficient of the interface are described and analyzed. The verification experiment is designed and carried out. By processing and analyzing the experimentally obtained heat map sequence of the material surface temperature variation, Heat storage coefficient of different hidden substances in the piece.