Verification of Plasticity Theory with Isotropic Hardening and Additive Decomposition of Left Deformation Tensor Using Digital Image Correlation System

2015 ◽  
Vol 240 ◽  
pp. 61-66 ◽  
Author(s):  
Marcin Gajewski ◽  
Cezary Ajdukiewicz ◽  
Andrzej Piotrowski
Keyword(s):  
Digital Image Correlation ◽  
Boundary Value Problems ◽  
Digital Image ◽  
Constitutive Relations ◽  
Boundary Value ◽  
Experimental Tests ◽  
Image Correlation ◽  
Deformation Tensor ◽  
Isotropic Hardening ◽  
Complex Boundary

The development of measurement methods, and in particular digital image correlation (DIC) systems, which are designed to measure of entire displacements and deformations fields, opens up new areas of research. In general, the materials constitutive relations are formulated in such a way that material parameters could be determined with relatively simple experimental tests carried out on samples with uniform (approximately) stress and strain fields. Then it is possible to apply them to complex boundary value problems formulated e.g. in the small or large deformation theories. The application of DIC allows to verify the accuracy of their predictions by comparing the results of the experiment with solutions to boundary value problems obtained using the finite element method (FEM).

scholarly journals Application of the 3D Digital Image Correlation to the Analysis of Deformation of Joints Welded With the FSW Method After Shot Peening

2019 ◽  
Vol 19 (4) ◽  
pp. 57-66
Author(s):  
A. Kubit ◽  
M. Bucior ◽  
R. Kluz ◽  
Ł. Święch ◽  
K. Ochał
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Shot Peening ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Image Correlation ◽  
X Ray Diffraction ◽  
Butt Joints ◽  
3D Digital Image Correlation ◽  
The Impact

AbstractThe three dimensional Digital Image Correlation (3D DIC) method is used for measurements of deformations and displacement in plane elements exposed to loading. The paper presents the experimental tests of an application of the ARAMIS system to the analysis of deformation of joints welded with the FSW method after shot peening treatment. The butt joints were made of 2024-T3 aluminum alloy sheets with the thickness of 1 mm, which next were peened with glass beads about granulation in range 500 ÷ 900 µm. Tests of residual stresses by X-ray diffraction were also carried out. The aim of the study was to analyze the impact of shot peening on the value of stresses and the location of deformations in butt joints.

A nonlinear simulation of a bi-failure specimen through improved discretisation methods: A validation study

2018 ◽  
Vol 53 (8) ◽  
pp. 616-629 ◽  
Author(s):  
Behzad V Farahani ◽  
Jorge Belinha ◽  
Paulo J Tavares ◽  
Pedro MGP Moreira
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Numerical Study ◽  
Interpolation Method ◽  
Yield Criterion ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Isotropic Hardening ◽  
Flow Rule ◽  
Nonlinear Simulation

A robust and efficient scheme is rendered to elastoplastically study the material nonlinearity of structural components. In this investigation, a specimen manufactured from the aluminium alloy AA6061-T6 is considered. It is mechanically loaded under a uniaxial tensile state and the experimental strain datum is analysed by three-dimensional digital image correlation. Due to specific specimen geometry, complex stress states will occur. However, the specimen yields due to an approximated uniaxial stress state. The obtained remote stress/strain from experimental data is used to validate the computational solutions using advanced discretisation approaches. Therefore, as a preliminary numerical study, the model is simulated through the finite element method formulation. Afterwards, another numerical strategy is adopted – the radial point interpolation method. The Newton–Raphson initial stiffness method is thereby adapted to complete the nonlinear solutions algorithm. Furthermore, the elastoplastic demeanour of aluminium alloys is determined with the von Mises yield criterion, an isotropic hardening rule and an associative flow rule. Obtained computational results fit the experimental digital image correlation solution, which allow to conclude that the proposed meshless methodology is efficient and reliable.

scholarly journals Determination of the Shear Modulus of Pine Wood with the Arcan Test and Digital Image Correlation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 468
Author(s):  
Piotr Bilko ◽  
Aneta Skoratko ◽  
Andrzej Rutkiewicz ◽  
Leszek Małyszko
Keyword(s):  
Digital Image Correlation ◽  
Shear Modulus ◽  
Digital Image ◽  
Structural Model ◽  
Experimental Tests ◽  
Plane Stress State ◽  
Image Correlation ◽  
Finite Element Program ◽  
Full Field ◽  
Principal Axes

Arcan shear tests with digital image correlation were used to evaluate the shear modulus and shear stress–strain diagrams in the plane defined by two principal axes of the material orthotropy. Two different orientation of the grain direction as compared to the direction of the shear force in specimens were considered: perpendicular and parallel shear. Two different ways were used to obtain the elastic properties based on the digital image correlation (DIC) results from the full-field measurement and from the virtual strain gauges with the linear strains: perpendicular to each other and directed at the angle of π/4 to the shearing load. In addition, the own continuum structural model for the failure analysis in the experimental tests was used. Constitutive relationships of the model were established in the framework of the mathematical multi-surface elastoplasticity for the plane stress state. The numerical simulations done by the finite element program after implementation of the model demonstrated the failure mechanisms from the experimental tests.

Benefits of using digital image correlation systems for advanced structural assessment

2021 ◽  
Author(s):  
Peter Harsányi ◽  
Tamás Mészöly ◽  
Edoardo Rossi ◽  
Norbert Randl
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Performance ◽  
Optical Measurement ◽  
Experimental Tests ◽  
Image Correlation ◽  
Advantages And Disadvantages ◽  
Non Invasive ◽  
Diverse Field ◽  
Displacement Transducers

<p>New developments in civil engineering in the area of innovative high-performance materials and sophisticated geometrical designs generate the need for advanced measurement and monitoring systems. Based on years of utilizing digital image correlation (DIC) in a diverse field of applications, the advantages and disadvantages of DIC measurements are highlighted, by means of a selection of various experimental tests conducted by the authors. Recommendations for a general methodology for the utilization of DIC systems are presented. For this purpose, the beneficial advantages in the case of a variety of different chosen test setups, as well as the originated evaluation data, are shown. Such a type of non invasive optical measurement system enables the user to gather data even in challenging conditions, where a brittle failure of the specimen has to be expected and conventional measurement equipment, like LVDTs or displacement transducers, reach their limit. In addition, a simplified model for a 3D measurement setup calculation is presented.</p>

scholarly journals Measuring geometric imperfections of variable-angle filament-wound cylinders with a simple digital image correlation (DIC) set up

2021 ◽  
Author(s):  
Saullo G. P. Castro ◽  
José Humberto S. Almeida ◽  
Luc St-Pierre ◽  
Zhihua Wang
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Experimental Tests ◽  
Variable Stiffness ◽  
Filament Winding ◽  
Image Correlation ◽  
Geometric Imperfections ◽  
Variable Angle ◽  
Filament Wound ◽  
Set Up

The experimental measurement of geometric imperfections of cylindrical shells is a fundamental step towards achieving representative models that are capable of capturing the imperfection-sensitive behavior of this type of shells and generate predictions that are comparable with experimental tests. The present study proposes an imperfection measurement method that is simple and applicable to both small and large structures, whereby the topographic data measured with one pair of cameras is obtained at six circumferential positions. Practical aspects of using digital image correlation are discussed, such as lighting and focus adjustments, and calibration. State-of-the-art best-fit routines are used to transform the obtained raw imperfection data onto a common coordinate system by means of least-squares optimization steps. Finally, the transformed data is stitched to build the full imperfection patterns that can be readily used in nonlinear finite element analyses. The developed method is demonstrated in the present study by measuring 12 variable-angle filament-wound cylinders, a novel class of variable-stiffness structures developed by our research group that combines a wide tailoring capability coming from the variable stiffness with the efficient manufacturability enabled by the filament winding process.

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