Inverse Contrast in Non-Destructive Materials Research by Using Active Thermography
| Autor: | Henryk Nowak, Paweł Noszczyk |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
thermal contrast
Materials science defect detection Acoustics Phase (waves) location of inclusions 02 engineering and technology lcsh:Technology 01 natural sciences Article thermovision law.invention law materials research Nondestructive testing 0103 physical sciences Thermal General Materials Science lcsh:Microscopy 010301 acoustics lcsh:QC120-168.85 lcsh:QH201-278.5 lcsh:T business.industry non-destructive testing 021001 nanoscience & nanotechnology Cladding (fiber optics) Oriented strand board active thermography lcsh:TA1-2040 Thermography lcsh:Descriptive and experimental mechanics lcsh:Electrical engineering. Electronics. Nuclear engineering lcsh:Engineering (General). Civil engineering (General) 0210 nano-technology Radiator business building partition lcsh:TK1-9971 Cooling down |
| Zdroj: | Materials Volume 12 Issue 5 Materials, Vol 12, Iss 5, p 835 (2019) |
| ISSN: | 1996-1944 |
| Popis: | Background: it is undesirable for defects to occur in building partitions and units. There is a need to develop and improve research techniques for locating such defects, especially non-destructive techniques for active thermography. The aim of the experiment was to explore the possibility of using active thermography for testing large-sized building units (with high heat capacity) in order to locate material inclusions. Methods: as part of the experiment, two building partition models&mdash one made of gypsum board (GB) and another made of oriented strand board (OSB)&mdash were built. Three material inclusions (styrofoam, granite, and steel), considerably differing in their thermal parameters, were placed in each of the partitions. A 7.2 kW infrared radiator was used for thermally exciting (heating) the investigated element for 30 min. The distribution of the temperature field was studied on both sides of the partition for a few hours. Results: using the proposed investigative method, one can detect defects in building partitions under at least 22 mm of thick cladding. At a later cooling down phase, inverse temperature contrasts were found to occur&mdash the defects, which at the beginning of cooling down were visible as warmer areas, at a later phase of cooling down are perceived as cooler areas, and vice versa (on the same front surface). In the transmission mode, the defects are always visible as areas warmer than defect-free areas. Moreover, a quantitative (defect location depth) analysis with an accuracy of up to 10% was carried out using the Echo Defect Shape method. Conclusions: active thermography can be used in construction for non-destructive materials testing. When the recording of thermograms is conducted for an appropriate length of time, inverse contrasts can be observed (on the same front surface). |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
| Nepřihlášeným uživatelům se plný text nezobrazuje | K zobrazení výsledku je třeba se přihlásit. |