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Displacement (vector)

About: Displacement (vector) is a research topic. Over the lifetime, 24669 publications have been published within this topic receiving 264944 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, a new methodology is proposed to estimate displacement fields from pairs of images (reference and strained) that evaluates continuous displacement fields, specialized to a finite-element decomposition.
Abstract: A new methodology is proposed to estimate displacement fields from pairs of images (reference and strained) that evaluates continuous displacement fields. This approach is specialized to a finite-element decomposition, therefore providing a natural interface with a numerical modeling of the mechanical behavior used for identification purposes. The method is illustrated with the analysis of Portevin–Le Châtelier bands in an aluminum alloy sample subjected to a tensile test. A significant progress with respect to classical digital image correlation techniques is observed in terms of spatial resolution and uncertainty.

654 citations

Journal ArticleDOI
TL;DR: In this article, a criterion for judging the relative effeciency of excitation of piezoelectric surface waves as a function of crystal plate orientation and propagation direction is developed based on a velocity change upon application of a thin conducting sheet to the surface.
Abstract: A criterion for judging the relative effeciency of excitation of piezoelectric surface waves as a function of crystal plate orientation and propagation direction is developed. This criterion is based on a velocity change upon application of a thin conducting sheet to the surface. Plots of surface wave velocity for various orientations of the crystal surface are presented as a function of propagation direction for the conducting sheet in contact with and infinitely far removed from the crystal surface. A plot of a typical velocity variation as a function of height of the conducting sheet is also presented. Evidence in support of the criterion of using velocity changes as an indicator of efficiency is presented in the form of mechanical displacement and electric potential plots for several orientations and propagation directions. All velocity displacements and potential calculations were carried out under the assumption that the crystal medium was lithium niobate.

641 citations

Patent
03 Oct 1997
TL;DR: In this paper, the displacement units are provided with force actuators which each have a first part (47, 49; 117, 119; 215, 217) which is coupled to the relevant object holder and which is displaceable under the influence of a driving force relative to a second part (59, 61; 133, 135, 137, 139; 219, 221) which was fastened to a balancing unit (69, 149, 205).
Abstract: A positioning device (3, 97, 179) with a first displacement unit (25, 189) for displacing a first object holder (11, 181) and a second displacement unit (27, 191) for displacing a second object holder (13, 183). The object holders can be displaced by the positoning device alternately from a measuring position into an operational position and can be displaced by the respective displacement units independently of one another in the measuring position and in the operational position. The displacement units are provided with force actuators which each have a first part (47, 49; 117, 119; 215, 217) which is coupled to the relevant object holder and which is displaceable under the influence of a driving force relative to a second part (59, 61; 133, 135, 137, 139; 219, 221) which is fastened to a balancing unit (69, 149, 205) which is common to the two displacement units. The balancing unit is displaceably guided relative to a base (81, 209), so that reaction forces of the displacement units are converted into displacements of the balancing unit relative to the base, and mechanical vibrations in the balancing unit and the base are prevented. The use of the force actuators prevents the displacements of the balancing unit from disturbing the positions of the object holders relative to the base. The positioning device is further provided with a control unit (83, 169, 237) by means of which at least the parts (47, 49; 121, 123; 219, 221) directed parallel to an X-direction of the X-actuators (39, 41; 105, 107; 211, 213) coupled to the object holders are held in positions parallel to the X-direction. It is also prevented in this manner that positions of the object holders relative to the base are interfered with by rotations of the balancing unit caused by the reaction forces of the displacement units. The positioning device can be used in a lithographic device for the displacement of a semiconductor substrate relative to an exposure system of the lithographic device and for the displacement of a mask relative to the exposure system.

641 citations

Journal ArticleDOI
TL;DR: In this article, an updated Lagrangian and a total Lagrangians formulation of a three-dimensional beam element are presented for large displacement and large rotation analysis, and it is shown that the two formulations yield identical element stiffness matrices and nodal point force vectors.
Abstract: An updated Lagrangian and a total Lagrangian formulation of a three-dimensional beam element are presented for large displacement and large rotation analysis. It is shown that the two formulations yield identical element stiffness matrices and nodal point force vectors, and that the updated Lagragian formulation is computationally more effective. This formulation has been implemented and the resulted of some sample analyses are given.

633 citations

Journal ArticleDOI
TL;DR: In this article, a general experimental calibration procedure is described which determines the magnification matrix of a distorted imaging system, and an algorithm is presented to compute accurate velocity field displacements from measurements of distorted PIV images.
Abstract: Optical distortion due to inaccurate optical alignment, lens nonlinearity, and/or refraction by optical windows, fluid interfaces, and other optical elements of an experiment causes inaccuracy by introducing variable magnification. Since fractional changes in the magnification have a one-to-one effect on the accuracy of measuring the velocity, it is important to compensate for such distortions. A general experimental calibration procedure is described which determines the magnification matrix of a distorted imaging system, and an algorithm is presented to compute accurate velocity field displacements from measurements of distorted PIV images. These procedures form a basis for generalized stereoscopic PIV procedures which permit easy electronic registration of multiple cameras and accurate recombination of stereoscopic displacement fields to obtain the three-dimensional velocity vector field.

625 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202240
2021725
2020932
20191,201
20181,027
20171,114