Infrared thermography for condition monitoring – A review

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.

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Infrared thermography for temperature measurement and non-destructive testing.

https://hal.archives-ouvertes.fr/hal-01005683/document

The detection of aeronautical defects in situ on composite structures using Non Destructive Testing

Ferromagnetic microwires enabled multifunctional composite materials

Impact resistance and damage tolerance are of great significance in the design of composite structures. This study investigated the damage and failure mechanism of thin composite laminates under low-velocity impact and compression-after-impact (CAI) loading conditions. Four levels of impact energy were included in the test matrix. Delamination induced by low-velocity impact was captured using ultrasonic C-scan, and a three-dimensional (3D) digital image correlation (DIC) system was employed to measure full-field displacement during the CAI tests. Infrared thermography was also used to online monitor the thermal field variation of the test specimen during the impact and CAI process. The cross sections of typical tested specimens were inspected using an optical microscope and a scanning electron microscope (SEM). A 3D damage model that considers both interlaminar and intralaminar damage was proposed to study the complex damage and failure mechanism. Excellent correlation was obtained between the experimental results and the numerical results. The experimental results obtained from various tests and the results from the numerical simulation were combined to provide a new and deep insight of damage evolution and failure mechanisms under low-velocity impact and CAI loading conditions.

Damage and failure mechanism of thin composite laminates under low-velocity impact and compression-after-impact loading conditions

Acoustic emission (AE) and infrared thermography (IT) are simultaneously combined to identify damage evolution in carbon fibre reinforced composites. Samples are subjected to tensile static loads while acoustic emission sensors and an infrared camera record the acoustic signals and the temperature variations respectively. Unsupervised pattern recognition procedure is applied to identify damage mechanisms from acoustic signals. Thermodynamic arguments are introduced to estimate global heat source fields from thermal measurements and anisotropic heat conduction behavior is taken into account by means of homogenization technique. A spatial and time analysis of acoustic events and heat sources is developed and some correlation range in the AE and IT events amplitude are identified.

/pdf/damage-detection-in-cfrp-by-coupling-acoustic-emission-and-nhahgsi4w2.pdf

Damage detection in CFRP by coupling acoustic emission and infrared thermography

Applying infrared thermography to study the heating of 2024-T3 aluminium specimens under fatigue loading

In this paper, a new fatigue life prediction methodology is proposed by combining stiffness degradation and temperature variation measured by InfraRed Thermographic (IRT) camera. Firstly, the improved thermographic method is used to determine the fatigue limit by using the data of stabilized temperature rising. Following this, a two-parameter model is proposed to characterize the stiffness degradation of CFRP laminates with the increase of cycle numbers. After the calibration parameters and the calculation of the normalized failure threshold stiffness, the whole S - N curve can be obtained in a very short time. The proposed model is applied to both the experimental data of triaxially braided CFRP laminates from literature and those of unidirectional CFRP laminates obtained from our fatigue tests. Results show that predicted S - N curves have a good agreement with traditional tests. The principal interests of this model could be listed as follows: (i) it is a more general criterion applicable to different materials; (ii) it has more physical senses; (iii) it allows the determination of the total S-N curve for composite materials in a short time.

/pdf/a-new-model-for-fatigue-life-prediction-based-on-infrared-ymmau91r6r.pdf

A new model for fatigue life prediction based on infrared thermography and degradation process for CFRP composite laminates

This work deals with the issue of damage growth in thin woven composite laminates subjected to tensile loading. The conducted tensile tests were monitored on-line with an infrared camera, and tested specimens were analysed using Scanning Electron Microscopy (SEM). Combined with SEM micrographs, observation of heat source fields enabled us to assess the damage sequence. Transverse weft cracking was confirmed to be the main damage mode and fiber breakage was the final damage leading to failure. For cracks which induce little variation of specimen stiffness, the classic “Compliance method” could not be used to compute energy release rate. Hence, we present here a new procedure based on the estimation of heat source fields to calculate the energy release rate associated with transverse weft cracking. The results are then compared to those computed with a simple 3D inverse model of the heat diffusion problem and those presented in the literature.

https://hal.archives-ouvertes.fr/hal-00858882/document

Damage analysis and fracture toughness evaluation in a thin woven composite laminate under static tension using infrared thermography

https://hal.archives-ouvertes.fr/hal-01924946/document

Marie-Laetitia Pastor

Papers

Damage detection in CFRP by coupling acoustic emission and infrared thermography

Applying infrared thermography to study the heating of 2024-T3 aluminium specimens under fatigue loading

A new model for fatigue life prediction based on infrared thermography and degradation process for CFRP composite laminates

Damage analysis and fracture toughness evaluation in a thin woven composite laminate under static tension using infrared thermography

Rapid evaluation of fatigue limit on thermographic data analysis