 | Large deformations |
 |
 | Finite Eulerian Elastoplasticity without Strain
Author : Meyers, A.;Xiao, H.;Bruhns, O.
Source : Defence Science Journal ; Vol:58(2) ; 2008 ; pp 194-199
Subject :
Keywords : Constitutive relations;Elastoplasticity;Eulerian formulation;Large deformations;Yield criterion
Abstract : In the last few decades a number of phenomenological models have been developed for describing elastoplastic materials undergoing finite deformations. They are different in structure, e.g., their formulation is related to the reference or to the actual configuration , i.e., it is a Lagrangean or Eulerian formulation or it may contain elastic and/or plastic deformations. This study has shown that the most simple and straightforward obtained constitutive relation is free from any notion of elastic or plastic deformation. Moreover, it is related to the actual configuration, and thus omits to the greatest possible extent, quantities containing unwanted geometric deformation informations. |
| | Adaptive meshing for deep drawing process
Author : Ahmed, Mohd;Sekhon, G. S.
Source : Defence Science Journal ; Vol:53(1) ; 2003 ; pp 51-56
Subject : 620.1 Material Science and Technology
Keywords : Adaptive meshing;Deep drawing;Finite element analysis;Large deformations
Abstract : "The paper incorporates the concept of adaptive meshing for finite-element analysis of the deep-drawing process. In adaptive meshing, the mesh is automatically refined both in the areas of insufficient accuracy and sharp stress gradients. The Zienkiewicz-Zhu error estimator based upon the difference between the finite-element solution and the corresponding smoothened solution is used to judge the accuracy both at the element and the global levels. The post-processing for determining more accurate solutions is done by fitting a higher order polynomial expansion to the finite-element solution in nodal patches. An illustrative problem is solved and the adaptive refinement at differention is presented. " |
| | Measurement of out of plane dynamic deformations by digital speckle pattern interferometry
Author : Rajesh Kumar;Chandra, Shakher
Source : Defence Science Journal ; Vol:53(1) ; 2003 ; pp 115-121
Subject : 620.1 Material Science and Technology
Keywords : Dynamic deformations;Large deformations;Histogram equalisation;Symlet wavelet;Daubechies wavelet;Phase filter;Wavelet filter;Minimum phase filter ;Digital speckle pattern interferometry;Signal to noise ratio
Abstract : In this paper, measurement of dynamic deformations in a rectangular plate fixed at one end, using digital speckle pattern interferometry (DSPI), has been presented. To improve the measurement accuracy, a new filtering scheme has been developed. This scheme is based on the combination of average/ median filtering and Symlet wavelet filtering which enhances the signal-to-noise ratio in the speckle interferogram obtained from the DSPI. Experimental results show that this filtering scheme is quite effective in improving signal-to-noise ratio of the speckle interferogram. The measurements by DSPI and accelerometer are in good agreement. The DSPI technique can be implemented for measuring the large deformations as well. |
|
