Design of infrared non-destructive testing for damage detection in multi-layer materials (original) (raw)
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The design of infrared non-destructive testing for investigation multi-layer materials
Proceedings of the 2012 International Conference on Quantitative InfraRed Thermography, 2012
The inverse heat conduction in a multi-material slab with periodic temperature excitation is investigated. We derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point in the material specimen. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an effective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula are assessed by comparison with analytical thermal quadrupoles solution.
Active Infrared Thermography in Non-destructive Testing
2009
The contribution deals with state of the art non-destructive testing method-active infrared thermography. The method can be used for revealing of defects and inhomogenities inside the bodies, e.g. bubbles and cracks in materials, which can have crucial importance from the point of view of their physical-mechanical properties. Goal of the research is theoretical evaluation of the performance of the pulse active thermography as non-destructive testing method and its experimental validation.
Active Infrared Thermography Techniques for the Nondestructive Testing of Materials
Ultrasonic and Advanced Methods for Nondestructive Testing and Material Characterization, 2007
Active infrared thermography refers to the group of methods employed to inspect the integrity of materials or systems through the use of an external energy source and an infrared detector. The external stimulus can be of many forms such as warm or cold air, heat pulses, periodic thermal waves, or mechanical oscillations, e.g. ultrasounds. The way data is captured and processed, as well as the typical applications differ according to the excitation source. This chapter presents a review of three of the most common active techniques in the field of thermography: pulsed thermography, lock-in thermography and vibrothermography.
Infrared Thermography for Temperature Measurement and Non-Destructive Testing
The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed.
Review Infrared Thermography for Temperature Measurement and Non-Destructive Testing
2014
The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed.
Infrared thermography is a nondestructive and evaluation technique in which the surface of the in- spected specimen is subjected to a thermal stimulation in order to produce a temperature difference between eventual surface or subsurface defects and non-defective zones. The classical signal processing techniques are based on thermal contrast computations, the simplest definition being the absolute contrast, defined as the arithmetic difference between a defective and a reference (defect-free) area. The absolute thermal contrast is af- fected by different problems such as emissivity variations, environmental reflections, non-uniform heating due to the energy source and surface shape. The impact of these problems can be considerably reduced through the normalization of the thermal contrast. Nevertheless, to carry out thermal contrast calculations, normalized or not, it is necessary to define a defect-free or sound area Sa, which is not always straightforward or possible to do. The dif...
Active infrared thermography as a method for non-destructive testing
17th Slovak-Czech-Polish Optical Conference on Wave and Quantum Aspects of Contemporary Optics, 2010
The contribution deals with state of the art non-destructive testing method-active infrared thermography. The method can be used for revealing of defects and inhomogenities inside the bodies, e.g. bubbles and cracks in materials, which can have crucial importance from the point of view of their physical-mechanical properties. Goal of the research is theoretical evaluation of the performance of the pulse active thermography as non-destructive testing method and its experimental validation.
Proceedings of the 2018 International Conference on Quantitative InfraRed Thermography, 2018
Inspecting low-thermal-conductivity materials via active thermographic non-destructive testing requires a long inspection time because of the slow heat transfer in such materials. This study focuses on reducing the inspection time by using thermal waves with a high-frequency component. Fourier transform was applied to extract the high-frequency component from the observed thermal data. Consequently, it was observed from analytical studies and experiments of a carbon-fiber-reinforced plastic and a concrete specimen that using phase data in the high-frequency range obtained from the transformed data is effective for the detection of internal defects within a short inspection time.
Active Thermography for Materials Non-Destructive Testing
2014
Active thermography is an advanced experimental procedure, which uses a thermography measurement of a tested material thermal response after its external excitation. This principle can be used also for non-contact infra-red non-destructive testing (IRNDT) of materials. The IRNDT method is based on an excitation of a tested material by an external source, which bring some energy to the material. Halogen lamps, flash-lamps, ultrasound generator or other source can be used as the excitation source for IR-NDT. The excitation causes a tested material thermal response, which is measured by an infra-red camera. It is possible to obtain information about the tested material surface and sub-surface defects or material inhomogeneities by using a suitable combination of excitation source, excitation procedure, infra-red camera and evaluation method. Active thermography and IR-NDT methods are introduced in this contribution. Different IRNDT configurations and their possibilities and limitations...