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1.
The failure criterion for a microvolume is characterized by its stress-rupture strength. It is determined by the dependence
of the time to brittle fracture on the difference between the equivalent stress and its limit, which is the ultimate strength,
according to the Schleicher–Nadai failure criterion, and assumed to be a random function of coordinates. An equation of damage
(porosity) balance in the layers at an arbitrary time is formulated taking into account the thermal component. Algorithms
of calculating the time dependence of microdamage and macrostresses are developed. Corresponding curves are plotted. The effect
of temperature on the deformation and microdamage of the layers is studied 相似文献
2.
A theory of long-term damage of particulate composite materials under thermal load is proposed. The damage of the composite
components is modeled by randomly dispersed micropores. The failure criterion for a single microvolume is determined by its
stress-rupture strength, which, in turn, is determined by the dependence of the time to brittle failure on the difference
between the equivalent stress and its limit, which characterizes the ultimate strength according to the Schleicher–Nadai criterion.
The damage (porosity) balance equation is derived for an arbitrary time, taking the thermal effect into account. Algorithms
for calculating microdamage and macrostresses as functions of time are developed 相似文献
3.
A theory of long-term damage of homogeneous materials under thermal load is proposed. The damage of the material is modeled
by randomly dispersed micropores. The failure criterion for a single microvolume is determined by its stress-rupture strength,
which, in turn, is determined by the dependence of the time to brittle failure on the difference between the equivalent stress
and its limit, which characterizes the ultimate strength according to the Schleicher–Nadai criterion. The damage (porosity)
balance equation is derived for an arbitrary time, taking the thermal effect into account. Algorithms for calculating microdamage
and macrostresses as functions of time are developed, and respective curves are plotted. The effect of temperature on the
macrodeformation and damage curves is studied 相似文献
4.
The theory of long-term damage is generalized to fibrous composites. The damage of the matrix is modeled by randomly dispersed
micropores. The damage criterion for a microvolume is characterized by its stress-rupture strength. It is determined by the
dependence of the time to brittle failure on the difference between the equivalent stress and its limit, which is the ultimate
strength, according to the Huber–von Mises criterion, and assumed to be a random function of coordinates. An equation of damage
(porosity) balance in the matrix at an arbitrary time is formulated. Algorithms of calculating the time dependence of microdamage
and macrostresses or macrostrains are developed and corresponding curves are plotted in the case of stress-rupture microstrength
described by an exponential power function 相似文献
5.
The theory of long-term damage is generalized to unidirectional fibrous composites. The damage of the matrix is modeled by
randomly dispersed micropores. The damage criterion for a microvolume is characterized by its stress-rupture strength. It
is determined by the dependence of the time to brittle failure on the difference between the equivalent stress and its limit,
which is the ultimate strength, according to the Huber–Mises criterion, and assumed to be a random function of coordinates.
An equation of damage (porosity) balance in the matrix at an arbitrary time is formulated. Algorithms of calculating the time
dependence of microdamage and macrostresses or macrostrains are developed and corresponding curves are plotted in the case
of stress-rupture microstrength described by a fractional power function 相似文献
6.
Deformation and long-term damage of orthotropic composites with limited stress-rupture microstrength
The theory of long-term microdamage of homogeneous materials based on the mechanics of stochastically inhomogeneous materials
is generalized to a composite with orthotropic inclusions. The damage of the composite components is modeled by randomly dispersed
micropores. The damage criterion for a microvolume is characterized by its stress-rupture strength. It is determined by the
dependence of the time to brittle failure on the difference between the equivalent stress and its limit, which is the tensile
strength, according to the Huber–Mises criterion, and assumed to be a random function of coordinates. Given macrostresses
or macrostrains, an equation of damage (porosity) balance in the composite components at an arbitrary time is derived. The
time dependence of microdamage and macrostresses or macrostrains in a discrete-fiber-reinforced composite with limited stress-rupture
microstrength described by a fractional-power function is plotted 相似文献
7.
A theory of long-term damage of physically nonlinear homogeneous materials is proposed. Damage is modeled by randomly dispersed
micropores. The failure criterion for a microvolume is characterized by its stress-rupture strength. It is determined by the
dependence of the time to brittle fracture on the difference between the equivalent stress and its limit, which is the ultimate
strength, according to the Huber–Mises criterion, and assumed to be a random function of coordinates. An equation of damage
(porosity) balance in a physically nonlinear material at an arbitrary time is formulated. Algorithms of calculating the time
dependence of microdamage and macrostresses are developed and the corresponding curves are plotted. The effect of the nonlinearity
of the material on its macrodeformation and damage is analyzed 相似文献
8.
The theory of long-term damage of homogeneous materials, which is based on the equations of the mechanics of stochastically
inhomogeneous materials, is generalized to composite materials reinforced with orthotropic ellipsoidal inclusions. The microdamage
of the composite components is modeled by randomly dispersed micropores. The failure criterion for a microvolume is characterized
by its stress-rupture strength. It is determined by the dependence of the time to brittle failure on the difference between
the equivalent stress and its limit, which is the tensile strength, according to the Huber–Mises criterion, and assumed to
be a random function of coordinates. Given macrostresses or macrostrains, an equation of porosity balance in the composite
components at an arbitrary time is formulated. The time dependence of microdamage and macrostresses or macrostrains is established
in the case of unlimited stress-rupture microstrength described by an exponential power function 相似文献
9.
The theory of long-term damage of homogeneous materials is generalized to layered materials. The damage of the components
(layers) is modeled by randomly dispersed micropores. The damage criterion for a microvolume is characterized by its stress-rupture
strength. It is determined by the dependence of the time to brittle failure on the difference between the equivalent stress
and its limit, which is the tensile strength, according to the Huber–Mises criterion, and assumed to be a random function
of coordinates. An equation of damage (porosity) balance in the components at an arbitrary time is formulated. Algorithms
of calculating the time dependence of microdamage and macrostresses or macrostrains are developed and corresponding curves
are plotted in the case of a fractional power microdurability function 相似文献
10.
The theory of long-term damage of homogeneous materials is generalized to layered materials. The damage of the components
is modeled by randomly dispersed micropores. The damage criterion for a microvolume is characterized by its stress-rupture
strength. It is determined by the exponential power dependence of the time to brittle failure on the difference between the
equivalent stress and its limit, which is the tensile strength, according to the Huber–Mises criterion, and assumed to be
a random function of coordinates. An equation of damage (porosity) balance in the components at an arbitrary time is formulated.
Algorithms of calculating the time dependence of microdamage and macrostresses or macrostrains are developed and corresponding
curves are plotted in the case of exponential power microdurability function 相似文献
11.
The theory of long-term damage of homogeneous materials is generalized to particulate composite materials. The damage of the
composite components is modeled by randomly dispersed micropores. The damage criterion for a microvolume is characterized
by its stress-rupture strength. It is determined by the dependence of the time to brittle failure on the difference between
the equivalent stress and its limit, which is the tensile strength, according to the Huber–Mises criterion, and assumed to
be a random function of coordinates. An equation of damage (porosity) balance in the composite components at an arbitrary
time is formulated. Algorithms of calculating the time dependence of microdamage and macrostresses or macrostrains are developed
and relevant curves are plotted in the case of unlimited microdurability
Translated from Prikladnaya Mekhanika, Vol. 44, No. 11, pp. 7–17, November 2008. 相似文献
12.
The theory of long-term damage of homogeneous materials is generalized to particulate composite materials. The damage of the
composite components is modeled by randomly dispersed micropores. The damage criterion for a microvolume is characterized
by its stress-rupture strength. It is determined by the dependence of the time to brittle failure on the difference between
the equivalent stress and its limit, which is the tensile strength, according to the Huber-Mises criterion, and assumed to
be a random function of coordinates. An equation of damage (porosity) balance in the composite components at an arbitrary
time is formulated. Algorithms of calculating the time dependence of microdamage and macrostresses or macrostrains are developed
and corresponding curves are plotted in the case of limited microdurability
Translated from Prikladnaya Mekhanika, Vol. 44, No. 10, pp. 3–12, October 2008. 相似文献
13.
The theory of long-term damage of homogeneous materials, which is based on the equations of the mechanics of stochastically
inhomogeneous materials, is generalized to discrete-fiber-reinforced composite materials. The microdamage of the composite
components is modeled by randomly dispersed micropores. The failure criterion for a microvolume is characterized by its stress-rupture
strength. It is determined by the dependence of the time to brittle failure on the difference between the equivalent stress
and its limit. Given macrostresses and macrostrains, an equation of damage (porosity) balance in the composite components
at an arbitrary time is formulated. The time dependence of microdamage and macrostresses or macrostrains is established in
the case of stress-rupture microstrength described by an exponential power function
Translated from Prikladnaya Mekhanika, Vol. 45, No. 2, pp. 19–29, February 2009. 相似文献
14.
The theory of long-term damage is generalized to particulate composite materials with physically nonlinear components. The
damage of the components is modeled by randomly dispersed micropores. The damage criterion for a microvolume is characterized
by its stress-rupture strength. It is determined by the dependence of the time to brittle failure on the difference between
the equivalent stress and its limit, which is the ultimate strength, according to the Huber–Mises criterion, and assumed to
be a random function of coordinates. An equation of damage (porosity) balance in the components at an arbitrary time is formulated.
Algorithms of calculating the time dependence of are developed. The effect on the nonlinearity of the matrix on the damage
and macrodeformation curves is examined 相似文献
15.
A microdamage theory is constructed for laminated fibrous materials with transversely isotropic fibers and a porous isotropic matrix under thermal actions. Microdamages in the matrix are simulated by pores, empty or filled with particles of the damaged material that resist compression. The fracture criterion for a microvolume of the matrix is assumed to have the Nadai–Schleicher form, which takes into account the difference between the tensile and compressive ultimate loads, with the ultimate strength being a random function of coordinates with a power or Weibull distribution. The stress–strain state and the effective properties of the material are determined from the thermoelastic equations for laminated fibrous materials with a porous matrix. The deformation and microdamage equations are closed by the porosity balance equations corrected for the thermal effect. For various types of loading, nonlinear relations are derived for the coupled processes of deformation of a laminated fibrous material and microdamage of the matrix due to the thermal macrostrain. The effect of physical and geometrical parameters on these processes is studied. 相似文献
16.
The theory of microdamage for materials with a transversely isotropic matrix and unidirectional ellipsoid-like fibers is set forth. Microdamage is modeled by empty pores. The failure criterion for a microvolume is assumed to have the Huber–Mises form where the ultimate strength is a random function of coordinates with a power or Weibull distribution. The stress–strain state and effective properties of the material are determined from the theory of elasticity for materials with a transversely isotropic matrix and unidirectional fibers. The deformation and microdamage equations are closed by the porosity-balance equations. The nonlinear dependences of the coupled processes of deformation and microdamage on macrodeformations are constructed. The effect of physical and geometrical parameters on the processes is studied 相似文献
17.
The studies of mathematical models for the coupled processes of deformation and long-time damage of stochastic composite materials
are systematized. Damage is modeled by stochastically arranged micropores. The damage of a single microvolume is characterized
by its stress-rupture strength determined by the dependence of the time to brittle fracture on the difference between the
equivalent stress and its limit, which is the ultimate strength, according to the Huber–Mises or Schleicher–Nadai criteria,
and assumed to be a random function of coordinates. The equation of damage balance at an arbitrary time and the equations
relating macrostresses and macrostrains constitute a closed system. Algorithms of calculating the time dependence of microdamage
and macrostresses are developed. The effect of temperature and nonlinearity on the curves is studied 相似文献
18.
The microdamage of porous transversely isotropic piezoelectric materials under complex macrostress is studied. The microdamages are modeled by pores. The damage of a microvolume is defined by the generalized Huber-Mises failure criterion for a transversely isotropic medium. The ultimate strength is a random function of coordinates with exponential or Weibull distribution. The stress-strain state and effective properties of the material are determined from the stochastic equations of electroelasticity. The deformation and microdamage equations are closed by the porosity balance equations. Deformation curves are plotted for two values of macrostrain or macrostress and different values of electric intensity. The influence of electric intensity on the microdamage of piezoelectric materials is studied__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 3, pp. 79–92, March 2005. 相似文献
19.
The structural theory of microdamage of homogeneous and composite materials is generalized. The theory is based on the equations
and methods of the mechanics of microinhomogeneous bodies with stochastic structure. A single microdamage is modeled by a
quasispherical pore empty or filled with particles of a damaged material. The accumulation of microdamages under increasing
loading is modeled as increasing porosity. The damage within a single microvolume is governed by the Huber-Mises or Schleicher-Nadai
failure criterion. The ultimate strength is assumed to be a random function of coordinates with power-law or Weibull one-point
distribution. The stress-strain state and effective elastic properties of a composite with microdamaged components are determined
using the stochastic equations of elasticity. The equations of deformation and microdamage and the porosity balance equation
constitute a closed-form system of equations. The solution is found iteratively using conditional moments. The effect of temperature
on the coupled processes of deformation and microdamage is taken into account. Algorithms for plotting the dependences of
microdamage and macrostresses on macrostrains for composites of different structure are developed. The effect of temperature
and strength of damaged material on the stress-strain and microdamage curves is examined
__________
Translated from Prikladnaya Mekhanika, Vol. 43, No. 6, pp. 3–42, June 2007. 相似文献
20.
The theory of microdamageability of fibrous composites with transversally isotropic fibers and a microdamaged isotropic porous matrix is proposed. Microdamages in the matrix are simulated by pores filled with particles of the destroyed material that resist compression. The criterion of damage in the matrix microvolume is taken in the Schleicher–Nadai form. It accounts for the difference between the ultimate tensile and compressive loads. The ultimate strength is a random function of coordinates with Weibull distribution. The stress–strain state and effective properties of the material are determined from the stochastic equations of the elastic theory for a fibrous composite with porous components. The equations of deformation and microdamage are closed by the equations of porosity balance in the matrix. Nonlinear diagrams of the concurrent processes of deformation of fibrous materials and microdamage of the matrix are plotted. The effect of the physical and geometrical parameters on them is studied 相似文献