Quantifying and visualising change: strain monitoring of tapestries with digital image correlation

A three-year research project at the University of Southampton (2007–2010) investigated whether monitoring techniques commonly used by engineers to assess the strength and durability of materials could be usefully applied to inform the condition assessment of historic tapestries. To date it has not been possible to obtain an objective picture of the overall condition of a tapestry; the study investigated whether it is possible to identify precursors of structural damage. The two techniques, digital image correlation (DIC) and optical fibre sensors, were used to monitor a representative wool fabric, specially woven tapestry samples, a newly woven tapestry, and historic tapestries, both in the laboratory and in situ in a historic house. This study first sets out to answer the question: can DIC be used to monitor and visualize strain in historic tapestries? It is shown that DIC can be used successfully. Secondly, it discusses the map function, a novel development which allowed the monitoring equipment to be moved, so that it could be used in situ in a historic house. Thirdly, it provides further details of the experimental work using optical fibre sensors to confirm the accuracy of the DIC technique

Application of Thermography for Assessment of Crack Propagation in Composites

This paper presents the preliminary work on the application of Telops Fast m3K infrared camera for strain energy release rate measurement in fibre failure of carbon fibre composites. The technique is shown for quasistatic loading of compact tension specimen and identifying the crack propagation and instantaneous crack lengths using local changes in temperature near the crack tip

COMBINED DIC-INFRARED THERMOGRAPHY FOR HIGH STRAIN RATE TESTING OF COMPOSITES

In this paper, simultaneous high-speed white-light and infrared imaging were conducted to obtain quantitative description of thermomechanical response of the material and to study the formation and propagation of shear localizations from the temperature history