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41.
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
42.
The studies on the deformation and short-term damage of physically nonlinear homogeneous and composite materials are systemized.
A single microdamage is modeled by an empty quasispherical pore in place of a microvolume damaged in accordance with the Huber–von
Mises failure criterion. The ultimate microstrength is assumed to be a random function of coordinates. The porosity balance
equation is derived. Together with the macrostress–macrostrain relationship, it constitutes a closed-form system of equations.
The damage–macrostrain relationship and macrostress–macrostrain curves for homogeneous and composite materials are analyzed 相似文献
43.
The structural theory of short-term damage is generalized to the case where the undamaged components of a granular composite deform nonlinearly. The basis for this generalization is the stochastic elasticity equations for a granular composite with porous components whose skeletons deform nonlinearly. Microvolumes of the composite components meet the Huber–Mises failure criterion. Damaged microvolume balance equations are derived for the physically nonlinear materials of the components. Together with the equations relating macrostresses and macrostrains of a granular composite with porous nonlinear components, they constitute a closed-form system. The system describes the coupled processes of physically nonlinear deformation and microdamage. Algorithms for calculating the microdamage–macrostrain relationship and plotting deformation diagrams are proposed. Uniaxial tension curves are plotted for the case where microdamages occur in the linearly hardened matrix and do not in the inclusions, which are linearly elastic 相似文献
44.
A structural theory of short-term microdamage is proposed for a two-component laminated composite with microdamageable reinforcement
and physically nonlinear matrix. The basis of the theory is the stochastic elasticity equations of a laminated composite with
a porous reinforcement. Microvolumes in the reinforcement material meet the Huber-Mises failure criterion. The damaged-microvolume
balance equation for the reinforcement is derived. This equation and the equations relating macrostresses and macrostrains
of a laminated composite with porous reinforcement and physically nonlinear matrix constitute a closed-form system of equations.
This system describes the coupled processes of physically nonlinear deformation and microdamage occurring in different composite
components. Algorithms for computing the microdamage-macrostrain relationships and deformation diagrams are developed. Uniaxial
tension curves are plotted for a laminated composite with linearly hardening matrix
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 12, pp. 3–12, December 2005. 相似文献
45.
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47.
A structural theory of short-term microdamage is proposed for a fibrous composite with physically nonlinear matrix and microdamaged
reinforcement. The theory is based on the stochastic elasticity equations of a fibrous composite with porous fibers. Microvolumes
of the fiber material are damaged in accordance with the Huber-Mises failure criterion. A balance equation for damaged microvolumes
in the reinforcement is derived. This equation together with the equations relating macrostresses and macrostrains of a fibrous
composite with porous reinforcement and physically nonlinear matrix constitute a closed-form system. This system describes
the coupled processes of physically nonlinear deformation and microdamage that occur in different components of the composite.
Algorithms are proposed for computing the dependences of microdamage on macrostrains and macrostresses on macrostrains. Uniaxial
tension curves are plotted for a fibrous composite with a linearly hardening matrix
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 2, pp. 3–13, February 2006. 相似文献
48.
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
49.
An algorithm is suggested to determine non-linear deformative properties of granular composite materials with non-linearly deformed porous components. Stochastic differential equations of physically non-linear elasticity theory with the following use of conditional averaging are assumed as a basis. Solution of non-linear equations with respect to conditional moment is constructed by the method of successive approximation. The volume content of the components and pores in the components have been studied for their effect on the character of the strain curves of porous granular composite. 相似文献
50.
The bifurcation instability problem for cylindrical shells made of particulate composites with nonlinear elastic inclusions
and damageable matrix is formulated and solved
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 10, pp. 68–79, October 2007. 相似文献