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The paper deals with the development of the technique for J-integral computation using the vector fields obtained by digital image correlation method. The proposed computing algorithm includes several steps following each other: (i) construction of displacement vector field; (ii) calculation of deformations and stresses; (iii) calculation of the J-integral value. A comparative study of the results obtained by the proposed technique and by finite element simulation was carried out. The errors of the data modeled in the ANSYS from the computed J-integral values were estimated at various tensile loads. [ABSTRACT FROM AUTHOR]

This paper presents a proposition of a computational algorithm to be applied for the assessment of fatigue strength of notched elements using the concept of the fictitious radius. It has been demonstrated that the fictitious radius is significantly dependent on the forecasted fatigue life and specimen's geometry. The results of computations are compared with experimental results for notched specimens made from C45 steel. [ABSTRACT FROM AUTHOR]

The paper studies the effect of frictional pretreatment on the change in the properties of the surface layer of austenitic stainless steel subsequently subjected to low-temperature ionic nitriding in electron beam plasma. Under friction-force loading, near the specimen surface there appear residual compressive stresses changing the stress state in the gradient surface layer. Two mathematical models of the process of ion nitriding have been constructed, which take into consideration the effect of residual stresses with a constant diffusion coefficient. Besides, one of the models considers the effect of internal compressive stresses arising in the surface layer during the process of nitriding. Algorithms based on the boundary element method (BEM) are proposed for solving boundary value problems. Model examples illustrating the work of the algorithms have been solved. [ABSTRACT FROM AUTHOR]

In this paper, we focus on the simulation of linear elastic behaviour of plates using a 3D approach which numerical cost only scales like a 2D one. In the case of plates, the kinematic hypothesis introduced in plate theories to go from 3D to 2D is usually unsatisfactory where one cannot rely on St Venant's principle (usually close to the plate edges). We propose to apply the PGD (Proper Generalized Decomposition) method [1] to the simulation of the linear elastic behavior of plates. This method allows us to separately search for the in-plane and the out-of plane contributions to the 3D solution, yielding significant savings in computational cost. The method is validated on a simple case and its full potential is then presented for the simulation of the behavior of laminated composite plates. [ABSTRACT FROM AUTHOR]

This paper presents the formulation of an axi-symmetric element based on an efficient method called 'Inverse Approach' (I.A.) for the numerical modeling of cold forging process. In contrast to the classical incremental methods, the Inverse Approach exploits the known shape of the final part and executes the calculation from the final part to the initial billet. The assumptions of the proportional loading and the simplified tool actions make the I.A. calculation very fast. The metal's incompressibility is ensured by the penalty method. The comparison with ABAQUS® and FORGE® shows the efficiency and limitations of the I.A. This simplified method will be a good tool for the preliminary preform design. [ABSTRACT FROM AUTHOR]

In the present paper we demonstrate the use of electron backscatter diffraction (EBSD) for high resolution elastic strain determination. Here, we focus on analysis methods based on determination of small shifts in EBSD pattern with respect to a reference pattern using cross-correlation algorithms. Additionally we highlight the excellent spatial and depth resolution of EBSD and introduce the use of simulated diffraction patterns based on dynamical diffraction theory for sensitivity estimation. Moreover the potential of EBSD for strain analysis of strained thin films with particular emphasis on appropriate target preparation which respect to occurring lattice defects is demonstrated. [ABSTRACT FROM AUTHOR]

The full-field non-destructive measurement of internal displacement and strain fields is of interest in many engineering applications. This paper describes an approach to measuring internal displacements and strains in metals which uses the correlation of ultrasonic speckle images of the internal structure of the material. This has the key advantage over optical surface displacement and strain measurement techniques in that internal information can be obtained. Experiments are described which use a 1-D ultrasonic array to map 2-D displacement fields for uniform translation and uniaxial tension of a metallic bar. The full matrix of transmit-receive signals from the array was post-processed to generate speckle images using a Fourier-domain imaging algorithm. Block-search cross-correlation was used to find the displacements of small sub-images corresponding to regions within the bar. Potential applications include characterising crack networks and creep damage detection. [ABSTRACT FROM AUTHOR]