Artem S. Semenov

Bio: Artem S. Semenov is an academic researcher from Saint Petersburg State Polytechnic University. The author has contributed to research in topics: Finite element method & Creep. The author has an hindex of 11, co-authored 81 publications receiving 603 citations. Previous affiliations of Artem S. Semenov include Saratov State Technical University & Dresden University of Technology.

Cracks in functionally graded materials

Abstract: The weight function method is described to analyze the crack growth behavior in functionally graded materials and in particular materials with a rising crack growth resistance curve. Further, failure of graded thermal barrier coatings (TBCs) under cyclic surface heating by laser irradiation is modeled on the basis of fracture mechanics. The damage of both graded and non-graded TBCs is found to develop in several distinct stages: vertical cracking → delamination → blistering → spalling . This sequence can be understood as an effect of progressive shrinkage due to sintering and high-temperature creep during thermal cycling, which increases the energy-release rate for vertical cracks which subsequently turn into delamination cracks. The results of finite element modeling, taking into account the TBC damage mechanisms, are compatible with experimental data. An increase of interface fracture toughness due to grading and a decrease due to ageing have been measured in a four-point bending test modified by a stiffening layer. Correlation with the damage observed in cyclic heating is discussed. It is explained in which way grading is able to reduce the damage.

On a vector potential formulation for 3D electromechanical finite element analysis

Abstract: A vector potential for the electric induction is applied to static three-dimensional fully coupled electromechanical problems. A Coulomb gauge condition imposed on the electric vector potential improves the convergence behaviour of nonlinear problems, and in combination with a discrete set of Dirichlet boundary conditions, it can enforce unique vector potential solutions. Based on a spectral analysis of the stiffness matrix, the Coulomb gauge is compared with other gauge conditions. A penalized version of the weak vector potential formulation with Coulomb gauge is proposed and tested on some numerical examples in electrostatics, piezoelectricity and ferroelectricity. Copyright © 2005 John Wiley & Sons, Ltd.

Return mapping algorithms and consistent tangent operators in ferroelectroelasticity

Abstract: Return mapping algorithms for a rather general class of phenomenological rate-independent models for ferroelectroelastic materials are presented. The fully coupled thermodynamically consistent three-dimensional constitutive model with two internal variables (remanent polarization vector and remanent strain tensor) proposed by C. M. Landis in 2002 is used for the simulation of electromechanical hysteresis effects in polycrystalline ferroelectric ceramics. Based on the operator splitting methodology, the return mapping algorithm employs the closest point projection scheme to obtain an efficient and robust integration of the constitutive model. The consistent tangent operator is obtained in closed form by linearizing the return mapping algorithm, and is found to be non-symmetric in the general case due to the dependence of the switching criterion on internal variables. Conditions that provide the symmetry of the consistent tangent matrix are analyzed. The compactness and generality of the received relations are achieved by means of using the thermodynamically based compact notations combining mechanical and electrical values. Both the cases scalar potential finite element (FE) formulation (primary variables: strain and electric field) and vector potential FE formulation (primary variables: strain and electric displacement) are considered. The accuracy and robustness of the algorithms are assessed through numerical examples. Copyright © 2009 John Wiley & Sons, Ltd.

Estimating the plastic strain with the use of acoustic anisotropy

Abstract: Experimental verification is used to show that reference specimens and structure unloading do not permit obtaining an adequate estimate of plastic strain by measuring the acoustic anisotropy. Analytic estimates of the speed of propagation of a plane acoustic wave of various polarizations in an elastoplastic material in the direction orthogonal to the action of preliminary uniaxial stress are obtained. An analysis of the obtained relations reveala an advantage of using absolute values of the velocity of longitudinal and transverse waves for the plastic strain identification. In contrast to acoustic anisotropy, the velocities vary monotonically in a wider range of plastic strains. At the same time, the elastic strain does not affect the longitude wave velocity, which allows one to use the measurement results to estimate the character of strains.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Modeling and Analysis of Functionally Graded Materials and Structures

Abstract: This paper presents a review of the principal developments in functionally graded materials (FGMs) with an emphasis on the recent work published since 2000. Diverse areas relevant to various aspects of theory and applications of FGM are reflected in this paper. They include homogenization of particulate FGM, heat transfer issues, stress, stability and dynamic analyses, testing, manufacturing and design, applications, and fracture. The critical areas where further research is needed for a successful implementation of FGM in design are outlined in the conclusions. DOI: 10.1115/1.2777164

Zeitschrift für angewandte mathematik und mechanik

Abstract: Ing. Holger Steeb, Dr.-Ing. Fehmi Cirak, Prof. Dr.-Ing. Ekkehard Ramm, University of Stuttgart, Department of Civil Engineering, Institute of Structural ...