A novel to perform a thermoelastic analysis using digital image correlation and the boundary element method (original) (raw)
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International Journal for Numerical Methods in Engineering, 2005
In this paper, the boundary element method (BEM) for solving quasi-static uncoupled thermoelasticity problems in materials with temperature dependent properties is presented. The domain integral term, in the integral representation of the governing equation, is transformed to an equivalent boundary integral by means of the dual reciprocity method (DRM). The required particular solutions are derived and outlined. The method ensures numerically efficient analysis of thermoelastic deformations in an arbitrary geometry and loading conditions. The validity and the high accuracy of the formulation is demonstrated considering a series of examples. In all numerical tests, calculation results are compared with analytical and/or finite element method (FEM) solutions.
A Boundary Elements and Particular Integrals Implementation for Thermoelastic Stress Analysis
International journal of engineering. Transactions A: basics, 2002
A formulation and an implementation of two-dimensional Boundary Element Method (BEM) analysis for steady state, uncoupled thermoelastic problems is presented. This approach differs from other treatments of thermal loads in BEM analysis in which the domain integrals due to the thermal gradients are to be incorporated in the analysis via particular-integrals. Thus unlike Finite Elements or Field Boundary Elements algorithms the domain discretization becomes unnecessary. The algorithm and the formulation are implemented in a general purpose, multi-region two- dimensional analysis. Isoparametric quadratic elements are employed to represent the geometry and the field variables. Examples are presented to demonstrate the accuracy and versatility of the method.
Thermoelastic analysis of 3D generally anisotropic bodies by the boundary element method
European Journal of Computational Mechanics, 2016
In the boundary element method (BEM) for stress analysis, it is well known that thermal loads give rise to an additional volume integral in the primary form of the boundary integral equation (BIE). This volume integral needs to be further transformed to surface ones in order to retain the characteristic of the BEM as a boundary solution technique. In this study of the BEM for 3D thermoelasticity in general anisotropy, the fundamental solutions are expressed as Fourier series with coefficients calculated using an explicit-form Green's function. In the exact volume-to-surface integral transformation associated with the term for the thermal effects in the BIE, a new kernel function is constructed. All formulations are implemented in an existing BEM code for 3D elastostatic analysis. Some numerical examples are presented to demonstrate the veracity of the formulations and the implementation, where the numerical results are compared with those obtained using the finite element method (FEM).
Validation of Numerical Model by Means of Digital Image Correlation and Thermography
Procedia Engineering, 2015
This paper presents experimental and numerical investigation of elasto-plastic-damage behaviour of aluminium alloys. The experimental procedure includes static and dynamic tensile tests at different strain rates as well as three point bending tests. Numerical modelling of deformation and failure process of the flat specimens is conducted by using non-isothermal elastoplastic damage constitutive model and two-dimensional plane stress finite elements. During the experiment the displacement and temperature distribution on the specimen's surface is measured by digital image correlation (DIC) method and infrared thermography (IR). This has enabled more precise calibration of material parameters in constitutive relations.
Comparison between Digital Image Correlation and Thermoelasticity for Strain Field Analysis
2010
The non contact measurement technique known as "Digital Image Correlation" (DIC) is a well known experimental method to analyze strain field on the surface of specimen and mechanical components, and since about 1980, for the development of high performance data processing and image acquisition systems, with a large number of applications in experimental mechanics. In this work, using the most recent data acquisition and processing techniques , performance and optimal selection of data acquisition and processing parameter are analyzed. To better understand the performance of this technique a comparison with thermoelastic images has been performed. The thermoelastic effect is usually used to investigate the stress field on surface of specimen or mechanical components (TSA: thermoelastic Stress Analysis) and can be demonstrated that this technique (TSA) can be useful to investigate the strain field too. This allow a direct comparison of results collected with DIC and thermoelastic strain analysis. Comparisons are performed measuring the first invariant of strain field on the surface of an AISI 304 thin test specimen with an hole on its center.
Engineering Analysis with Boundary Elements, 1998
A boundary element method is developed for time-harmonic analysis of a finite two-dimensional structure in dynamic coupled thermoelasticity. The advantage of the proposed technique is although it assumes a harmonic excitation, domain discretization is not required and a single region analysis can be done. The boundary integral equations of displacement and temperature fields are considered and a single thermal Hub ScienceDirect Scopus SciTopics Applications Article Figures/Tables (6) References (20) A new time domain b Engineering Analysis Application Engineering Analysis Evaluation Engineering Analysis The simulation and a
Time dependent axisymmetric thermoelastic boundary element analysis
A boundary element method is developed for problems of quasistatic axisymmetric thermoelasticity. Unlike previous approaches, this new time domain formulation is written exclusively in terms of surface quantities, thereby eliminating the need for volume discretization. Furthermore, since the exact three-dimensional infinite space fundamental solutions are employed, very accurate solutions are obtainable, including the determination of surface stresses.
Efficient Boundary Element Formulation of Thermoelasticity
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016), 2016
The problem of thermoelasticity is present in many different areas of solid mechanics. It describes the effects of thermal as well as mechanical loads on an elastic structure. We use the uncoupled quasistatic formulation of thermoelasticity (UQT), in a linear model and apply the Boundary Element Method. The UQT formulation is applicable in most cases, where the mechanical load is constant or slowly varying in time. Here, the influence of the elastic deformations on the heat distribution is neglected. This leaves us with a decoupled system of differential equations, consisting of the heat equation and an elastic equation, which accounts for thermal and mechanical loads. In the elastic equation the thermal field variables are introduced via convolutions. We apply three different methods for the calculation of these convolutions to find the elastic field variables and compare their computation times.
2017
Determining the strain flow and stress distribution in metallic materials during their deformation represents a significant challenge for researchers. The foil strain gage gave the possibility to test the actual stress in the deformation zone. Their application at higher deformations has proven to be limited, and does not give information on the entire deformation zone. With the development of digital technology, methods of digital image correlation (DIC) and thermography were developed. Their applications in researches today are more frequent, and are commonly being used for studying deformation of metals. The aim of this study was to determine the possibility of applying DIC method parallel with thermography to monitor the stresses distribution in deformation zone during the static tensile testing. The possibility of measuring with both methods on the same side of the sample, and the impact of markers required for DIC on the thermographic measurements, were tested. It has been pro...