共查询到20条相似文献,搜索用时 31 毫秒
1.
R. A. Abirov 《Journal of Applied Mechanics and Technical Physics》2009,50(1):107-111
A model of plasticity for a transversely isotropic material with allowance for complex loading is developed, based on results
of experiments with homogeneous cylindrical specimens of isotropic materials. An empirical model of plasticity for isotropic
metals is constructed with allowance for vector properties of the material. The model is extended to a particular case of
anisotropy.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 1, pp. 128–133, January–February, 2009. 相似文献
2.
The method of successive approximations is used to determine the thermoelastoplastic stress-strain state of isotropic and
transversally isotropic laminated shells of revolution under axisymmetric loading. Hill’s theory of plasticity with isotropic
hardening is used to describe the deformation of transversely isotropic materials, while the theory of deformation along paths
of small curvature is used to describe the deformation of isotropic materials. The elastoplastic stress-strain state of a
two-layer cylindrical shell under mechanical and thermal loads is analyzed
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 6, pp. 71–80, June 2006. 相似文献
3.
E. I. Romenskii 《Journal of Applied Mechanics and Technical Physics》2007,48(3):437-444
Constitutive equations that describe the experimentally observed failure waves are proposed to model inelastic strains of
brittle materials. The complete system of equations is hyperbolic, each equation of this system has divergent form. The model
is based on the assumption that continual failure is the process of transition from an intact state to a “fully damaged” state
described by the kinetics of the order parameter. The structure of stationary traveling compressive waves is analyzed using
a simplified model. It is shown that in a certain range of amplitudes, the wave splits into an elastic precursor and a failure
wave.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 164–172, May–June, 2007. 相似文献
4.
S. V. Golovin 《Journal of Applied Mechanics and Technical Physics》2008,49(5):725-736
A submodel of the equations of ideal magnetohydrodynamics is constructed that generalizes the classical motion of an ideal
continuous medium with plane waves. It is shown that, in contrast to classical motion, in this submodel the velocity and magnetic-field
vectors can change direction in a plane orthogonal to a distinguished spatial direction. The submodel is described by a system
of equations with two independent variables and a finite relation specifying the orientation of the vector fields in space.
The solutions of the submodel define substantially spatial processes and singularities in the motion of continuous media which
cannot be studied in the classical one-dimensional formulation.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 5, pp. 27–40, September–October, 2008. 相似文献
5.
M. Ya. Brovman 《Mechanics of Solids》2011,46(3):357-367
The plane strain of an ideal rigid-plastic medium is studied in curvilinear coordinates. The methods used to solve the equations
of plasticity were considered in [1–3]. Curvilinear orthogonal coordinates with the introduction of a metric function were
used in [4, 5]. 相似文献
6.
V. M. Sadovskii 《Journal of Applied Mechanics and Technical Physics》2009,50(3):519-524
An exact solution that describes the fields of displacements and stresses in an expanding spherical layer is constructed within
the framework of the theory of small strains of a granular medium with rigid particles. For finite strains, the problem reduces
to a nonlinear system of ordinary differential equations, which is solved by numerical methods. Similar solutions are found
in the problem for a cylindrical layer. Based on these solutions, the effect of the dilatancy of the granular medium on the
stress-strain state near expanding cavities is found.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 190–196, May–June, 2009. 相似文献
7.
V. M. Teshukov 《Journal of Applied Mechanics and Technical Physics》2007,48(3):303-309
The classical shallow-water equations describing the propagation of long waves in flow without a shear of the horizontal velocity
along the vertical coincide with the equations describing the isentropic motion of a polytropic gas for a polytropic exponent
γ = 2 (in the theory of fluid wave motion, this fact is called the gas-dynamic analogy). A new mathematical model of long-wave
theory is derived that describes shear free-boundary fluid flows. It is shown that in the case of one-dimensional motion,
the equations of the new model coincide with the equations describing nonisentropic gas motion with a special choice of the
equation of state, and in the multidimensional case, the new system of long-wave equations differs significantly from the
gas motion model. In the general case, it is established that the system of equations derived is a hyperbolic system. The
velocities of propagation of wave perturbations are found.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 8–15, May–June, 2007. 相似文献
8.
S. E. Alexandrov E. A. Lyamina 《Journal of Applied Mechanics and Technical Physics》2005,46(6):883-890
The following two models of the plasticity theory are considered: the model with the Mohr-Coulomb yield criterion and the
classical model of the plasticity theory with a yield criterion independent of the mean stress. The deformation problem of
a plastic layer enclosed between two rotating plates is studied.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 136–145, November–December, 2005. 相似文献
9.
I. O. Bolotina V. I. Danilov A. A. Zagumennyi 《Journal of Applied Mechanics and Technical Physics》2008,49(3):484-490
The deformation behavior of commercially pure submicrocrystalline and coarse-grained titanium was studied at the macroscopic
level. Stress-strain curves of the materials were analyzed. Time-space distributions of local strains were studied at all
stages of strain hardening using speckle interferometry. The life time of test specimens of the materials and the coordinates
of the fracture region were calculated theoretically and confirmed experimentally. The motion of the zones of localized plasticity
was studied. The prefracture stage was shown to involve “condensation” of the zones of localized plasticity and migration
of deformation to the fracture neck.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 164–172, May–June, 2008. 相似文献
10.
A dynamic bulge testing technique is developed to perform biaxial tests on metals at high strain rates. The main component
of the dynamic testing device is a movable bulge cell which is directly mounted on the measuring end of the input bar of a
conventional split Hopkinson pressure bar system. The input bar is used to apply and measure the bulging pressure. The experimental
system is analyzed in detail and the measurement accuracy is discussed. It is found that bars made of low impedance materials
must be used to achieve a satisfactory pressure measurement accuracy. A series of dynamic experiments is performed on aluminum
6111-T4 sheets using viscoelastic nylon bars to demonstrate the capabilities of the proposed experimental technique. The parameters
of the rate-dependent Hollomon–Cowper–Symonds J2 plasticity model of the aluminum are determined using an inverse analysis
method in conjunction with finite element simulations. 相似文献
11.
Experimental evidence for length scale effects in plasticity has been provided, e.g., by Fleck et al. (Acta Metall. Mater.
42:475–487, 1994). Results from torsional loadings on copper wires, when appropriately displayed, indicated that, for the
same shear at the outer radius, the normalized torque increased with decreasing specimen radius. Modeling of the constitutive
behavior in the framework of micropolar plasticity is a possibility to account for length scale effects. The present paper
is concerned with this possibility and deals with the theory developed by Grammenoudis and Tsakmakis (Contin. Mech. Thermodyn.
13:325–363, 2001; Int. J. Numer. Methods Eng. 62:1691–1720, 2005; Proc. R. Soc. 461:189–205, 2005). Both isotropic and kinematic
hardening are present in that theory, with isotropic hardening being captured in a unified manner. Here, we discuss isotropic
hardening composed of two parts, responsible for strain and gradient effects, respectively. 相似文献
12.
G. Sh. Boltachev N. B. Volkov V. V. Ivanov S. N. Paranin 《Journal of Applied Mechanics and Technical Physics》2008,49(2):336-339
A model for dynamic compaction of granular medium is proposed for the case in which the external action far exceeds the yield
strength of the material. A radial axisymmetric compaction problem is solved for a granular medium with nanosize structure
in the presence of a rigid rod at the symmetry axis. Simulated data are compared with experimental data on magnetic pulsed
compaction of oxide nanopowders.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 211–215, March–April, 2008. 相似文献
13.
A. I. Khromov A. A. Bukhan'ko O. V. Kozlova S. L. Stepanov 《Journal of Applied Mechanics and Technical Physics》2006,47(2):274-281
Based on the theory of an ideal rigid-plastic body, an approach is formulated for determining fracture constants on the basis
of standard mechanical tests on uniaxial extension of plane and cylindrical samples. Instead of the experimentally determined
characteristics of fracture of materials (dimensionless elongation and constriction of the sample during its fracture), two
invariant tensor characteristics of the degree of sample deformation are introduced, which correspond to the moment of origination
of a macrocrack and critical strain at the crack tip determining the process of crack propagation.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 2, pp. 147–155, March–April, 2006. 相似文献
14.
In this paper, we propose a formulation for modeling macroscopic traffic flow using a modified speed–density relationship.
The flow model consists of a nonlinear hyperbolic system of conservation laws. The proposed modification distinguishes between
acceleration and deceleration by assuming a different equilibrium velocity for a given traffic density based on whether a
platoon of vehicles is accelerating or decelerating. We examine the appropriateness of this modification to two prominent
traffic flow models in a Lagrangian reference frame, which we solve computationally. We show that a Lagrangian coordinate
system is ideal for the incorporation of the proposed modification due to its ability to track the behavior of moving vehicles.
We see that the modification is particularly well suited to “second order” models. 相似文献
15.
A solution of an initial-boundary-value problem for a system of integrodifferential equations which describes the plane waves
excited in an initially stationary heavy two-layer ideal fluid by a cylinder moving at an angle to the horizontal is investigated.
The homogeneous fluid fractions of different densities are assumed to be separated by an evolving fluid interface (horizontal
plane, if the liquid is at rest). An approximate solution of two problems for the waves excited by a cylinder moving with
a constant acceleration and an oscillating cylinder is constructed analytically.
Nizhnii Novgorod. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 137–152, July–August,
1998. 相似文献
16.
B. D. Annin 《Journal of Applied Mechanics and Technical Physics》1999,40(2):347-353
Specific features of the theories of ideal plasticity which are based on the Tresca yield criterion and the maximum reduced
stress criterion are discussed. An analysis is carried out in terms of the canonical basis of the deviatoric stress tensor.
Lavrent’ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 2, pp. 181–188, March–April, 1999. 相似文献
17.
V. M. Greshnov 《Journal of Applied Mechanics and Technical Physics》2008,49(6):1021-1029
Scalar and tensor models of plastic flow of metals extending plasticity theory are considered over a wide range of temperatures
and strain rates. Equations are derived using the physico-phenomenological approach based on modern concepts and methods of
the physics and mechanics of plastic deformation. For hardening and viscoplastic solids, a new mathematical formulation of
the boundary-value plasticity problem taking into account loading history is obtained. Results of testing of the model are
given. A numerical finite-element algorithm for the solution of applied problems is described.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 6, pp. 159–169, November–December, 2008. 相似文献
18.
V. Yu. Liapidevskii 《Journal of Applied Mechanics and Technical Physics》1998,39(2):194-199
A hyperbolic shallow-water model is constructed with allowance for nonlinear and dispersive effects. The model describes solitonlike
solutions in a range of wave velocities and predicts the breaking of smooth waves when the limiting amplitude is attained.
The model is found to be adequate by comparison with experimental data on the evolution of a wave packet generated by the
moving lateral wall of a channel.
Lavrent'ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 2, pp. 40–46, March–April, 1998. 相似文献
19.
A method is proposed for constructing a system of constitutive equations of an incompressible medium with nonlinear dissipative
properties with finite deformations. A scheme of the mechanical behavior of a material is used, in which the points are connected
by horizontally aligned elastic, viscous, plastic, and transmission elements. The properties of each element of the scheme
are described with the use of known equations of the nonlinear elasticity theory, the theory of nonlinear viscous fluids,
and the theory of plastic flow of the material under conditions of finite deformations of the medium. The system of constitutive
equations is closed by equations that express the relation between the deformation rate tensor of the material and the deformation
rate tensor of the plastic element. Transmission elements are used to take into account a significant difference between macroscopic
deformations of the material and deformations of elements of the medium at the structural level.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 158–170, May–June, 2009. 相似文献
20.
É. A. Tkanchenko 《International Applied Mechanics》1999,35(6):561-566
The problems of surface stability of laminated coatings subjected to the combined effect of tracing surface loads and a stationary
temperature field is considered. The material of the layer and the base are considered linearly elastic and trasversally isotropic.
Fulfillment of conditions of absolutely rigid force and ideal contacts are assumed between the individual elements of the
laminar medium. The subcritical stress state of the laminar medium under consideration is piecewise-homogeneous.
Interbranch Engineering Center “Tribotekhnika”, Dnepropetrovsk, Ukraine. Translated from Prikladnaya Mekhanika, Vol. 35, No.
6, pp 32–38, June, 1999. 相似文献