PSI - Issue 13

W. Teraud / Procedia Structural Integrity 13 (2018) 238–242 Teraud W. / Structural Integrity Procedia 00 (2018) 000–000

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Fig. 1. (a) The scheme of the method; Specimens (b).

Option 1 (Option A , without B, C ) had a semitransparent optical wedge at an angle of 45° to which there was a direct light source installed (Lamp), Figure 1a. The lamp light on the wedge refracted at 90° falling onto the specimen. This enabled direct visual access to the specimen illuminated. But this illumination resulted in a bright speck of light in the middle of the specimen. The second illumination system, or Option 2 (Option B , without A, C ) used an optical light guide made of sapphire. The light guide was inserted into the furnace via a small hole. The quantity of light through the guide was not sufficient; furthermore, as this was difficult to uniformly illuminate the sample, these problems did not make it possible to use that system. The third system (Option С , without A, B ) had two lamps inside the furnace. Initially, there was only one lamp, but to improve reliability during longer experiments another one was installed. To increase the lamp service life when exposed to temperatures above 400°C, the Controller was updated in such a way so that, shortly before sending a signal to the camera, it also switched on the lamp. 2.1. The Program To process pictures taken, one has written a software package to include “Recognizer”, “Solver” and “Post processor”. Figure 2a shows the general structure of the software.

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Fig. 2. The structure of programs (a); A virtual specimen (b).