The effects of motion on thermoelastic stress analysis

Hemelrijck, Danny Van; Schillemans, L.; Cardon, Albert; Wong, A.K.

doi:10.1016/0263-8223(91)90034-v

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…Motion compensation becomes impor- tant in order to avoid 'edge effects' and blurring of the signal when data are collected at higher spatial resolutions. Edge effects occur at the specimens' outer edges, at discontinuities with respect to thermoelastic properties or in a wider sense also when a thermal gradient is present [19]. Details on the motion compensation routine can be found in reference [6].…”

Section: Experimental Arrangementsmentioning

confidence: 99%

Characterization of local effects at core junctions in sandwich structures using thermoelastic stress anaylsis

Johannes

Dulieu-Barton

Bozhevolnaya

et al. 2008

The Journal of Strain Analysis for Engineering Design

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Local effects at core junctions in sandwich structures are studied using thermoelastic stress analysis (TSA). At the core junctions, large stress gradients occur owing to local bending of the face sheets and tension and compression of the adjacent cores. In the neighbourhood of large stress gradients it is known that non-adiabatic behaviour occurs which causes significant departures from the isentropic assumption that underpins TSA. Analytical estimates of the boundaries of adiabatic behaviour are made which show that TSA cannot capture the local effects using practical loading frequencies with thin aluminium face sheets, and this is confirmed experimentally. An experimental model of the sandwich beam is designed that shows that the local effects can be captured using TSA. It is also demonstrated that TSA can be used to assess local effects in sandwich constructions with glass-fibre-reinforced plastic face sheets. Reference data obtained from independently validated finite element analyses were used for comparison with the TSA results. A discussion on the effect of surface pattern and the introduction of noise due to motion is included in the paper. The data are presented in terms of stress and calibration tests on the constituent materials are carried out and reported in the paper.

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Section: Experimental Arrangementsmentioning

confidence: 99%

Characterization of local effects at core junctions in sandwich structures using thermoelastic stress anaylsis

Johannes

Dulieu-Barton

Bozhevolnaya

et al. 2008

The Journal of Strain Analysis for Engineering Design

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“…Nevertheless, committed bands of TSA researchers and practitioners around the world did (and continue to) produce much new knowledge in the field. Since that early beginning, DSTO played an active role in contributing to this knowledge base which includes the first report of the mean stress effect followed shortly by a revision of the thermoelastic theory by the inclusion of second order terms that could account for this phenomenon as well as demonstrating that this could potentially be used to determine residual stresses ; combining TSA with analytical and numerical methods to determine stress components ; the quantification of the frequency effect for composites applications and the reporting of motion effects for damaged composites along with the development of a real‐time motion compensation algorithm to rectify them .…”

Section: The Photon Detector Era: Sensing From a Distancementioning

confidence: 99%

50^th Anniversary Article: Seeing Stresses through the Thermoelastic Lens—A Retrospective and Prospective from an Australian Viewpoint

Wong

Rajic

Nguyen

2014

Strain

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Thermoelastic stress analysis (TSA) has been around for the past 30 years, but to date, it is still a very much underrated and under‐utilised experimental technique. Although there are devoted groups of practitioners in some industries, this technology is not well known within the aerospace sector. In contrast, the Aerospace Division of the Defence Science and Technology Organisation (DSTO) in Australia has been in the forefront of this technology for some time, achieving many pioneering feats. This paper gives a brief introduction to the development of this technology from a historical perspective, then focuses on a number of innovations that have stemmed from DSTO, including the development and application of the world's first focal plane array based TSA system and, more recently, the development of small and robust microbolometer based systems. For the latter, it is shown that despite nominally poorer temperature sensitivities, they make ideal TSA devices and can in some cases outperform their much more expensive photon detector counterparts. Because of this, together with the enormous practical advantages of microbolometers, the future of TSA is shown to be brighter than ever. Specifically, it is argued that such TSA systems can play a major role in the pervasive and persistent surveillance of full scale fatigue testing of aircraft structures. By detecting both design and developing faults early, it can effectively relieve cost and schedule penalties that are often associated with unanticipated failures. To realise this capability, integration of this technology with autonomous systems will be important, and some preliminary but promising results from a technology demonstrator program are presented.

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“…A literature survey of the application of quantitative TSA to FRPs reveals that a good majority of work has focused on GRPs with CFRPs addressed to a somewhat less extent [5–9, 13, 17–22]. It is interesting to note that most of these papers on CFRPs are from early work, but contain important basic developments about the extension of TSA to orthotropic composites in general.…”

Section: The Thermoelastic Effect In Cfrp Laminasmentioning

confidence: 99%

“…The first material is a laminate made out of AS4/3502 graphite‐epoxy pre‐pregs. This is a high‐grade CFRP material already considered in some previous studies [8, 20]. Reference to this material is only theoretical, with the analytical evaluation of the thermoelastic signal based on material properties taken from the literature (see Table 3 and Figure 2).…”

Section: Theoretical Predictions Of Thermoelastic Signalmentioning

confidence: 99%

A Quantitative Analysis of the Thermoelastic Effect in CFRP Composite Materials

Pitarresi

Galietti

2010

Strain

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In this study the thermoelastic signal from carbon fibre-reinforced plastic (CFRP)\ud laminates is investigated. A comparison between the theoretical and experimental values of the thermoelastic signal is reported, with the theoretical predictions obtained from two different quantitative models. These models are based on the classic thermoelastic effect law extended to the case of orthotropic materials (by using the mesomechanical or bulk approach), and the modified law assuming that the surface resin-rich layer behaves as a strain witness of the laminate. It is found that the theoretical predictions of the two models can be strongly and differently influenced by the intrinsic orthotropy of carbon fibres. Some effects are highlighted in particular such as the influence\ud of the laminate lay-up and the strong mismatch between the thermal expansion coefficients of the polymer matrix and the fibres. These influences are investigated analytically, predicting the thermoelastic\ud signal from various lay-ups and using strain-based and stress-based analytical models.\ud Experimental evidence of some theoretical findings is provided by reporting on tests performed on CFRP tensile samples manufactured from low-crimp unidirectional fabrics

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The effects of motion on thermoelastic stress analysis

Cited by 9 publications

References 11 publications

Characterization of local effects at core junctions in sandwich structures using thermoelastic stress anaylsis

Characterization of local effects at core junctions in sandwich structures using thermoelastic stress anaylsis

50^th Anniversary Article: Seeing Stresses through the Thermoelastic Lens—A Retrospective and Prospective from an Australian Viewpoint

A Quantitative Analysis of the Thermoelastic Effect in CFRP Composite Materials

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The effects of motion on thermoelastic stress analysis

Cited by 9 publications

References 11 publications

Characterization of local effects at core junctions in sandwich structures using thermoelastic stress anaylsis

Characterization of local effects at core junctions in sandwich structures using thermoelastic stress anaylsis

50th Anniversary Article: Seeing Stresses through the Thermoelastic Lens—A Retrospective and Prospective from an Australian Viewpoint

A Quantitative Analysis of the Thermoelastic Effect in CFRP Composite Materials

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Product

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50^th Anniversary Article: Seeing Stresses through the Thermoelastic Lens—A Retrospective and Prospective from an Australian Viewpoint