SOME NEW IDEAS IN NUMERICAL APPROACH TO THERMAL NON DESTRUCTIVE TESTING PROBLEMS

The paper presents the results of the research carried out on two samples made of different material by means of transient thermography. One sample is made of phenoxy resin and another one of phenoxy resin reinforced with cooper fibers. The experiments have been done together with numerical simulation. The goal of the research was to find the possibility of using numerical simulation for prediction of the results before starting with real experiment. Namely numerical analysis enable one to simulate a set of experiments on the computer and to select the proper parameters for real one. The further advantage of the numeric is a possibility for observing the temperature fields on various planes inside the sample. 1. INTRODUCTION Numerical approach in detection and quantification of the subsurface defects in TNDT gives a significant results in confirmation of the basic parameters of the defect characteristic such as maximal contrast and maximal contrast of the contrast curve versus time. The numerical simulation of a heat transfer through the object with the subsurface defect is based on the application of the control volume method combined with the inverse method. It has been carried out with the aim to find the possibility of making software, which will enable the correct description of the internal structure of the sample. For that the start and boundary conditions, as well as the geometrical characteristic of the sample and the defects must be known. In the work presented two models having the same shape but made of different materials were analyzed. The results were used to predict the behavior of the sample made of the mixture of both materials. 2. SAMPLES