Detection of Abnormal Regions by Full-Field Non-Contact TemperatureMeasurement and Inverse Analysis with the Aid of the MathematicalAnalysis

对于结构完整性的评估，对劣化或异常材料性能的检测和评估是非常重要的。本文提出了一种由二维全场温度分布估算材料热导率分布的方法。假设热流在感兴趣的区域内几乎是恒定的，根据温度梯度来估计导热系数。对正方形区域内导热系数的估算进行了数值模拟。估算的导热系数分布与实际热导率分布基本吻合，但在导热系数突变点附近，估算的导热系数分布有所恶化。由于该区域的通量不是恒定的，估计值变差了。由温度梯度得到流线。流线之间的宽度被用来修正导热系数的估计值。结果表明，流线宽度对导热系数分布有较好的估计效果。

For the assessment of structural integrity, the detection and evaluation of deteriorated or anomalous material properties are very important. If full field measurement of some physical quantity related to the material property is available, it is possible to construct a robust and accurate method for estimating the distribution of material properties.In this investigation, we propose a method for estimating thermal conductivity distribution from two-dimensional full field temperature distribution under certain thermal conditions. Assuming that heat flux is nearly constant in the region of interest, thermal conductivity is estimated from the temperature gradient. Numerical simulations were made of the estimation of thermal conductivity in a square region. The estimated distribution of thermal conductivity agreed reasonably with the actual one, while the estimation deteriorated around a point where thermal conductivity showed abrupt change. The estimation deteriorated due to the fact that the flux was not constant in the region. Streamlines were obtained from the temperature gradient. The width between streamlines was used for modifying the estimated value of thermal conductivity. It was found that a better estimation of the thermal conductivity distribution was made by using the width of streamlines.