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A new full-field motion compensation technique based on digital image correlation was developed for infrared thermoelastic stress measurements. Speckle patterns with variable infrared emissivity were applied to a test sample for motion analysis. Infrared images of the speckle pattern were acquired under the same loading conditions as for thermoelastic stress measurement. Displacements and deformations on the test sample were analysed using digital image correlation based on information on movement of the speckle patterns. Full-field motion compensation was performed in subsequent thermoelastic stress measurements based on the results of displacement measurements. The feasibility of the proposed motion compensation technique is demonstrated experimentally for thermoelastic stress measurement and identification of local plasticity at the stress-concentrated area in a plate specimen with a circular hole.

For bonded dissimilar materials, the free-edge stress singularity usually prevails near the intersection of the free-surface and the interface. When two materials are bonded by using an adhesive, an interlayer develops between the two bonded materials. When a ceramic and a metal are bonded, the residual stress develops because of difference in the coefficient of thermal expansion. An interlayer may be inserted between the two materials to defuse the residual stress. Stress field near the intersection of the interface and free-surface in the presence of the interlayer is then very important for evaluating the strength of bonded dissimilar materials.In this study, stress distributions on the interface of bonded dissimilar materials with an interlayer were calculated by using the boundary element method to investigate the effect of the interlayer on the stress distribution. The relation between the free-edge singular stress fields of bonded dissimilar materials with and without an interlayer was investigated numerically. It was found that the influence of the interlayer on the stress distributions was confined within a small area of the order of interlayer thickness around the intersection of the interface and the free-surface when the interlayer was very thin. The stress distribution near the intersection of the interface and the free-surface was controlled by the free-edge stress singularity of the bonded dissimilar materials without the interlayer. In this case, the interlayer can be called free-edge singularity-controlled interlayer. If a stress distribution on the interface is known for one thickness of an interlayer h, stress distributions on the interface for other values of h can be estimated.