engleski

Possibilities of Determinmation and Characterization of Subsurface Defects in Material by means of Thermography andD 3D Numerical Model

The paper presents the method for determination and characterization of subsurface defects in material by means of IR thermography and 3D non-stationary numerical model of heat conduction. The numerical model is based on the control volume numerical method with control volume net adjustable to the problem. The software developed enable the record of temperatures field in different planes and time as well as changing the duration of thermal stimulation time. Inverse method is also included and enables the estimation of defect length on the base of experimentally obtained thermograms. The method was applied on the specimen made of steel with the defects in form of cylinders containing air. The comparison of temperature fields obtained experimentally and numerically was done for the same time expired as well as the dependence of the current contrast vs. time curves related to the defects depth. The mutual interaction of defects on the surface temperature field was analyzed and their influence on the current contrast determined with the aim to recognize the possible errors in determination of defect geometry and position.

subsurface defects; numerical method; thermography method

nije evidentirano