Eugen Soós's research while affiliated with Romanian Academy and other places

Publications (22)

Article
One considers an unbounded, anisotropic elastic body containing an elliptical hole free from external loads but loaded by shear stresses far from the hole. The anti-plane equilibrium of the anisotropic elastic body is determined by using the complex representation of the anti-plane elastic states and the conformal mapping technique. The solution is...
Article
Full-text available
To describe the behavior of Shape Memory Alloy we use a thermomechanical model, founded on a free energy which is a convex function with respect to the strain and to the martensitic volume fraction, and a concave one with respect to the temperature. The material parameters of the model are experimentally determined.
Article
The problem considered is the antiplane deformation in prestressed and prepolarized piezoelectric crystals in equilibrium. The representation of the general solution is derived in terms of complex potentials for all piezoelectric crystal classes in which an antiplane state is possible. This generalizes earlier results obtained in respect of a speci...
Article
This is a comprehensive, reader-friendly treatment of the theory behind modern elastic composite materials. The treatment includes recently developed results and methods drawn from research papers published in Eastern Europe that until now were unavailable in many western countries. Among the book's many notable features is the inclusion of more th...
Article
The equations describing the incremental response of a thermoelastic solid under pre-existing mechanical and thermal fields are derived. The associated differential system is shown to be self-adjoint. This property in turn is used to establish the equivalence of linear static and dynamic stability criteria.
Article
Griffith’s notion of energy-release rate is extended to the linearized incremental theory of prestressed and pre-polarized piezoelectric crystals under suitable restrictions on the pre-existing fields.
Article
Griffith's notion of energy-release rate is extended to the linearized incremental theory of prestressed and pre-polarized piezoelectric crystals under suitable restrictions on the pre-existing fields.
Article
We analyze the consequences of Sih’s fracture criterion in a material which behaves according to the Cosserat-type model with free or constrained rotations. Both models are considered and for each of them the first and the second fracture mode is analyzed. To apply Sih’s criterion, the singular part of the stress field and of the couple stress fiel...
Article
Full-text available
The equations describing the behaviour of a hyperelastic dielectric under pre-existing mechanical and electrical flelds are derived. The associated difierential system is shown to be self-adjoint. This property, in turn, is used to establish the equivalence of linear static and dynamic stability criteria.
Article
The general complex‐variable solution to the equations of incremental antiplane piezoelectricity is used to solve the problem of crack propagation in a crystal in the presence of an initial stress and electric field. Remote incremental antiplane tractions are specified and an incremental traction of the same intensity is applied to the crack...
Article
In the present paper, we study interactions between initial elastic deformations and electric fields in a piezoelectric crystal with respect to the propagation of progressive waves in such crystals. We assume the elastic dielectric to be linear and homogeneous, the initial homogeneous deformations are infinitesimal, and the initial applied electric...
Article
We study piezoelectric crystals under antiplane strain in the presence of preexisting mechanical and electrical fields. The general representation of the solution is derived for the crystal class 42 m in terms of complex potentials.
Article
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In Part I of the paper we use a simplied 1D thermomechanical model to describe the behavior of SMAs. We prove that this model can describe the existence of the hysteresis loop and the pseudoelastic behavior of SMAs. In Part II of the paper we show that the same model predicts the stress relaxation and the strain creep during martensitic transformat...
Article
Full-text available
To describe the behavior of SMA we use a thermomechanical model, founded on a free energy which is a convex function with respect to the strain and to the martensitic volume fraction, and a concave one with respect to the temperature. The material parameters of the model are experimentally determined. In part I we prove that the model can describe...
Article
We apply Sih’s energetical fracture criterion to determine the critical incremental shear stress producing crack propagation in the third fracture mode, as well as the direction of crack propagation in a prestressed orthotropic or isotropic elastic material and compare the results obtained with those given by the classical Griffith-Irwine brittle f...
Article
Full-text available
We use a simplified ID version of a 3D thermomechanical model presented by Pham, to describe relaxation and creep in shape memory alloys (SMAs) during stress-induced martensitic transformation. We show that these rheological phenomena are predicted by taking into account, in the heat propagation equation, a thermomechanical coupling associated with...
Article
Full-text available
We use a simplified 1D version of a 3D thermomechanical model presented by Pham, to describe relaxation and creep in shape memory alloys (SMAs) during stress-induced martensitic transformation. We show that these rheological phenomena are predicted by taking into account, in the heat propagation equation, a thermomechanical coupling associated with...
Article
We consider an elastic orthotropic material representing a fiber reinforced composite. The composite is prestressed and contains two collinear cracks having different lengths. The faces of the cracks are acted by symmetrically distributed constant normal incremental stresses. We determine the critical values of the applied incremental stresses for...
Article
I start with the theory of small deformations and fields superposed on large static deformations and fields, given by Eringen and Maugin (Electrodynamics of Continua, Vol. 1, Foundations and Solid Media. Springer, New York (1990); Section 7.14). The considered body is an elastic dielectric and the quasi-static approximation is used. In the paper ar...
Article
We consider a homogeneous, isotropic, hyperelastic solid, containing a crack. The body is supposed to be strongly deformed in a particular way. We show that the resonance phenomenon can appear, the incremental fields becoming unbounded in the whole prestressed body. We also show that the asymptotic behaviour of the incremental fields in a small nei...
Article
Criteria are obtained for the propagation of antiplane waves in class-23 piezoelectric crystals subject to initial deformations and electric fields. The influence of initial deformations and electric fields on the stability of these crystals is also studied.

Citations

... Using the system of equations characterizing small stresses and electric fields superposed on a prestressed and prepolarized configuration, (see [4]- [6]), we obtain sufficient conditions for the existence of an antiplane state and the general solutions in terms of complex potentials for antiplane states of a prestressed and prepolarized crystal, (see [7], [8]). ...
... The main goal of this paper was to establish stability conditions and to analyze the stress concentration for prestressed piezoelectric materials containing a crack. In this direction E. Soós and his collaborators obtained notable developments in papers [1,2,3,5,6,7]. ...
... Various state-of-the-art techniques have been used to enhance the thermal performance of heat exchangers. For example, the cooling of automotive engines [1][2][3][4][5], heat sinks using nanofluids [6][7][8][9][10][11][12][13], space heating via heat exchangers [14][15][16][17][18], cooling electronic devices using heat-pipe radiators [19][20][21], and refrigerant/oil miscibility analysis in refrigeration systems [22,23] have been studied. The compact flat-tube louvered fin heat exchanger has widespread applications in heat pumps, air-conditioning, and refrigeration systems in residential, industrial, and automotive sectors. ...
... where K represents the stress intensity factor corresponding to Mode III of fracture, [7]- [8], ...
... The stress-induced phase transformation in NiTi wires subjected to tension is usually tracked in-situ by measuring sudden changes of strain and strain rates, both evaluated either integrally using displacement of the testing machine's cross-head, more accurately using clip-on extensometer, or locally using digital image correlation. Thermal Field Measurements (TFM), based on the use of an infrared (IR) camera [4][5][6][9][10][11] are an alternative way of tracking in-situ the phase transformation in NiTi. In general, TFM takes advantage of temperature changes that always accompany material stretching due to thermomechanical couplings and intrinsic dissipation: thermoelastic coupling, latent heat due to solid-solid phase change, self-heating due to plasticity, viscosity or fatigue damage. ...
... Several methods, based on different thermal models (0D, 1D or 2D), have been proposed to obtain heat source estimations from the temperature measurements of the material. They were applied to study energy balances in CuZnAl materials (Peyroux et al., 1998a;Chrysochoos et al., 1996;Balandraud et al., 2005), to study the homogeneous or localized thermomechanical behaviour of NiTi tubes, and to compare to DSC results (Delobelle, 2012). ...
... As a consequence, the temperature at the surface is nearly equal to the mean temperature over the volume. The heat diffusion equation can be written in this case [8,[11][12][13]: ...
... Sheokand et al. [16] examined the FGM under a dual-phase-lag model with rotation and gravity. Craciun and Soos [17] discussed elliptical hole crack problem in an infinite anisotropic elastic body of a fiber reinforced composite. ...
... A. If the cracks are equal (Cases 1, 2, 5,7,8,10,12,13) and: -the distance between them is much smaller as their common length (Cases 1, 2, 5) i.e. the interaction between the cracks is strong; we observe that , the inner tips start to propagate the first and the cracks tend to unify; -the distance between them is greater or approximate equal as their common length (Cases 8, 10,12,13) i.e. there is no, or weak, interaction between the cracks; we observe that , all tips start to propagate almost in the same time. B. If the cracks have different lengths (Cases 3, 4, 6,9,11) and: -the lengths of the cracks are greater as the distance between them (Case 3) i.e. the interaction between the cracks is strong; the minimum value of , 1,4 correspond to inner tip of longer crack and this inner tip will propagate the first; -the lengths of the cracks are smaller as the distance between them (Cases 4, 6,9,11) i.e. the interaction between the cracks is weak; the minimum values of , 1,4 correspond to both tips of the longer crack and these tips will propagate the first. ...
... During last two decades fracture for one crack in piezoelectric materials have been extensively studied in literature using analytical methods (complex variable technique, integral transforms methods, etc.), numerical approaches and experimental studies. In the fundamental papers of Sosa (see [1]- [2]), Pak (see [3]- [4]) and Soos (see [5]- [10]) was analyzed the behavior of piezoelectric materials with a crack or a hole using complex potentials. To the author's knowledge there are no analytical studies on cracks interaction in pre-stressed and pre-polarized materials using complex potentials technique. ...