a b s t r a c tThe effect of out-of-plane motion (including out-of-plane translation and rotation) on two-dimensional (2D) and three-dimensional (3D) digital image correlation measurements is demonstrated using basic theoretical pinhole image equations and experimentally through synchronized, multi-system measurements. Full-field results obtained during rigid body, out-of-plane motion using a singlecamera vision system with (a-1) a standard f55mm Nikon lens and (a-2) a single Schneider-Kreuznach Xenoplan telecentric lens are compared with data obtained using a two-camera stereovision system with standard f55mm Nikon lenses.Results confirm that the theoretical equations are in excellent agreement with experimental measurements. Specifically, results show that (a) a single-camera, 2D imaging system is sensitive to out-of-plane motion, with in-plane strain errors (a-1) due to out-of-plane translation being proportional to DZ/Z, where Z is the distance from the object to the pin hole and DZ the out-of-plane translation displacement, and (a-2) due to out-of-plane rotation are shown to be a function of both rotation angle and the image distance Z; (b) the telecentric lens has an effective object distance, Z eff , that is 50 Â larger than the 55 mm standard lens, with a corresponding reduction in strain errors from 1250 ms/mm of outof-plane motion to 25 ms/mm; and (c) a stereovision system measures all components of displacement without introducing measurable, full-field, strain errors, even though an object may undergo appreciable out-of-plane translation and rotation.

Ultra high-speed and moderate speed image acquisition platforms have been characterized, with special emphasis on the variability and accuracy of the measurements obtained when employed in either 2D or 3D computer vision systems for deformation and shape measurements. Specifically, the type of image distortions present in both single channel cameras (HS-CMOS) and multi-channel image intensified cameras (UHS-ICCD) are quantified as part of the overall study, and their effect on the accuracy of experimental measurements obtained using digital image correlation have been determined. Results indicate that established methods for noise suppression and recently developed models for distortion correction can be used effectively in situations where the primary intensity noise components are characterized by minimal cross-talk and stationary spatial distortions. Baseline uniaxial tension experiments demonstrate that image correlation measurements using high speed imaging systems are unbiased and consistent with independent deformation measurements over the same length scale, with point-to-point strain variations that are similar to results obtained from translation experiments. In this study, the point-to-point variability in strain using the image intensified system is on the order of 0.001, whereas the non-intensified system had variability of 0.0001. Results confirm that high speed imaging systems can be utilized for full field two and three-dimensional measurements using digital image correlation methods.

This paper deals with the analysis of an aluminium beam impacted in a three point bending configuration using a Hopkinson bar device. Full-field deformation measurements were performed using Digital Image Correlation on images captured with an ultra high speed camera (16 frames at a time resolution of 10 μs). The performance of the deformation and strain measurements were evaluated and the data were then used quantitatively to analyse the very complex dynamic behaviour of the beam. It was shown that the deformation of the beam was controlled by the interaction between the striker and the flexural bending wave triggered by the initial impact. The principle of virtual work was used to reconstruct the impact force from the shear strains and to analyze how this impact force relates to the acceleration of the specimen (inertia forces) and the development of the bending stresses. The results are in good agreement with expectations. This opens up new perspectives in the quantitative use of full-field measurements to extract elasto-plastic constitutive parameters from such impact tests.

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An ecological optimization along with a detailed parametric study of an irreversible regenerative Brayton heat engine with isothermal heat addition have been carried out with external as well as internal irreversibilities. The ecological function is defined as the power output minus the power loss (irreversibility) which is ambient temperature times the entropy generation rate. The external irreversibility is due to finite temperature difference between the heat engine and the external reservoirs while the internal irreversibilities are due to nonisentropic compression and expansion processes in the compressor and the turbine respectively and the regenerative heat loss. The ecological function is found to be an increasing function of the isothermal-, sink-and regenerative-side effectiveness, isothermal-side inlet temperature, component efficiencies and sink-side temperature while it is found to be a decreasing function of the isobaric -side temperature and effectiveness and the working fluid heat capacitance rate. T he effects of the isobaric-side effectiveness are found to be more than those of the other parameters and the effects of turbine efficiency are found to be more than those of the compressor efficiency on all the performance parameters of the cycle. B = a5T5+a6 C = b5T5 2 + b6 T5 + c5 a 8 = (a 5 a 7 -2Ab 7 )/a 7 a 9 = a 5 2 -4Ab 5 a 10 = a 5 a 6 -2Ab 6 a 11 = a 5 -2aa 10 /a 9 a 12 = a 5 2 -4ab 5 a 13 = a 5 a 6 -2ab 6 x 0 = (1+t 0 /t h ) x 2 = ε L (1/T L -1/T H )T 0 x 5 = a 7 x 0 + x 4 ε L x 6 = b 7 x 0 + (1-ε R )x 4 A 1 = a 12 -(a 12 /a 11 ) 2 B 1 = a 13 -a 12 a 13 /a 11 2 C1 = A 6 2 -4AC5 -(A13/A11) 2 K1 = C W εHTH (1-ε H1)+CW εH1TH 1+CW ε LTL

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