基于有限元的材料红外无损检测研究

Research on material infrared nondestructive testing based on finite element

通过有限元求解材料的二维导热模型,利用ANSYS仿真获取材料表面的温度分布,把表面温度计算值和仿真结果的误差平方和作为目标函数,借助于共轭梯度法来优化该目标函数。仿真结果验证了算法的可行性,可以达到红外无损检测的目的。研究表明:材料内部缺陷深度和材料的热导率是影响表面温差的重要因素,缺陷距离表面的深度越小,材料表面的温差越大;材料表面温差随热导率的增加呈现为先增大后减小的趋势。该方法可获得材料内部缺陷较为准确的位置和缺陷大小信息,为红外成像无损检测提供了可行的手段。

Finite element method is used to analyze the two-dimension heat transfer model.The temperature distribution on material surface can be obtained by using ANSYS simulation.The sum of errors function square is defined as the objective function.The errors function is the difference between the calculated values and simulation results of the material surface temperature.Conjugate gradient method is used to optimize this objective function.The simulation results certifies the feasibility of the algorithm.Study shows that the subsurface defect depth and thermal conductivity of materials are important factors that affect the temperature difference of the material surface.The smaller the depth of the defect from the surface is,the greater the temperature difference of the material surface is.With the increase of thermal conductivity,temperature difference of the material surface increases at first and then decreases.This method can obtain more accurate defect location and the defect size.It provides a feasible way for infrared nondestructive testing.