Integration of laser-speckle and finite-element techniques of stress analysis

Weathers, J.; Foster, Winfred A.; Swinson, W. F.; Turner, John E.

doi:10.1007/bf02329127

Cited by 30 publications

(7 citation statements)

References 7 publications

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“…That is, the displacements at the region where the measurement values cannot be obtained or unreliable can be obtained by solving the finite element equation [9, 10, 13]. Other hybrid methods that calculate displacements and strains from measured values along the boundaries of a finite element model have also been proposed by several researchers [9, 10, 14–16].…”

Section: Introductionmentioning

confidence: 99%

Smoothing Measured Displacements and Computing Strains Utilising Finite Element Method

Yoneyama

2011

Strain

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A method for smoothing measured displacements and computing strains utilising finite element and least-squares methods is proposed. Nodal displacement values of a finite element model are determined by fitting the interpolation functions of elements to measured displacement values using the method of least-squares. The displacements in the region where the measurement values are not obtained or unreliable are determined by solving finite element equations. Then, strains are obtained using a displacement-strain relationship. The validity is demonstrated by applying the proposed method to the displacement distributions of a plate with a hole obtained using finite element method and those around a crack tip obtained using digital image correlation. Results show that the displacements and the strains can be determined accurately by the proposed method. Furthermore, the strains near free boundaries and strain concentration region can be computed. As strains can be evaluated easily and accurately, the proposed method can be used as one of the data processing methods for optical methods.KEY WORDS: digital image correlation, displacement, finite element method, hybrid method, least-squares method, optical methods, strain 258 Ó

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Section: Introductionmentioning

confidence: 99%

Smoothing Measured Displacements and Computing Strains Utilising Finite Element Method

Yoneyama

2011

Strain

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“…18 -20 Most of the EOT-FEM comparative analysis have been done on simple 2-D structures. [1][2][3][4][5][6][7][8][9][10] Seeing the displacement contours obtained by optical technique with contour maps obtained by FEM usually requires qualitative comparisons. In quantitative comparisons, it is common to select a line on both maps or define bilinear 2-D map to define the correlation.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Material mechanical properties, loading and boundary conditions, and geometry validated through experiment are used in optimizing the numerical models.…”

Section: Introductionmentioning

confidence: 99%

Mapping correlation algorithm as interface between experimental optical technique and computer modeling for the study of mechanical structures

2001

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To create a hybrid system applied to mechanical structure analysis link to experimental optical techniques (EOTs) and computer modeling (CM), the correlation problem between CM and EOT methods must be solved. A mapping correlation algorithm (MCA) is proposed as the interface between both techniques. Out-of-plane electronic speckle pattern interferometry (ESPI) as the experimental optical technique and a commercial finite element method (FEM) package are employed. The MCA proposed is based on a set of mapping functions, which are found by least-squares algorithms and enable the compensation of image distortions produced by the experimental optical setup. The algorithm was tested initially on a simple 2-D structure and two 3-D complex mechanical structures. Results are reported. Further, the MCA algorithm linking ESPI-FEM methods is applied to out-of-plane displacements over a rectangular plate under stress. Numerical and experimental results along with their error analysis are also presented.

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“…The MS was received on 3 December 1999 and was accepted after revision for publication on 23 ing bodies, as well as hybrid experimental and numerical methods for analyses of solids [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…ing bodies, as well as hybrid experimental and numerical methods for analyses of solids [12,13]. Consider a homogeneous isotropic linear elastic twodimensional solid ¿ , bounded by its boundary ¡ .…”

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confidence: 99%

Development of new inverse boundary element techniques in photoelasticity

Chen

Becker

Jones

et al. 2001

The Journal of Strain Analysis for Engineering Design

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This paper presents a number of possible algorithms for inverse boundary element (BE) techniques applied to photoelastic analysis. The BE technique is shown to be an ideal companion to photoelastic analysis since, unlike the finite element (FE) method, the interior solutions can be represented by unconnected points rather than by discretized elements. From the photoelastic principal stress information obtained at a sufficient number of internal points, the unknown boundary conditions can be reconstructed using the inverse boundary element method (BEM). The inverse BE theory and numerical formulation are presented for problems involving Cartesian stress components and are then extended to photoelastic stress analysis. The inverse BE approach follows two stages. In stage 1, the photoelastic stress measurements of the differences in principal stresses and their directions at the interior points are used to compute the unknown boundary conditions on the surface. In stage 2, the individual stress components are calculated by the forward BEM using the computed boundary conditions from stage 1. The effect of scatter of the experimental results is also included in the analysis. A number of examples are presented in this paper and are shown to be in excellent agreement with other solutions.

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Integration of laser-speckle and finite-element techniques of stress analysis

Cited by 30 publications

References 7 publications

Smoothing Measured Displacements and Computing Strains Utilising Finite Element Method

Smoothing Measured Displacements and Computing Strains Utilising Finite Element Method

Mapping correlation algorithm as interface between experimental optical technique and computer modeling for the study of mechanical structures

Development of new inverse boundary element techniques in photoelasticity

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