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Description of the elastic deformation and degradation of elastic properties of dispersedly failing isotropic materials 总被引:1,自引:1,他引:0
A model is put forward for describing the elastic deformation of a quasi-homogeneous isotropic material capable of accumulating
scattered microdamages during loading, which eventually leads to its total failure. The degree of damage of the material at
a point is characterized by a centrosymmetric scalar function on the unit sphere, named the damage function, whose values
depend on a dimensionless equivalent stress. This function is approximated by a fourth-rank tensor, which is used to construct
a constitutive relation between stresses and strains in a differential form. By way of example, the elastic deformation of
concrete and the degradation of its linearly elastic properties are described, and the basic three-dimensional sections of
the corresponding strength surface are constructed.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 2, pp. 193–208, March–April, 2006. 相似文献
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L. Nazarenko L. P. Khoroshun W. H. Müller B. R. Wille 《Mechanics of Composite Materials》2009,45(1):11-20
A model of deformation of stochastic composites subjected to microdamage is developed for the case of orthotropic materials
with microdamages accumulating in the fibers. The composite is treated as a matrix strengthened with elliptic fibers with
orthotropic elastic properties. The fractured microvolumes are modeled by a system of randomly distributed quasi-spherical
pores. The porosity balance equation and relations for determining the effective elastic moduli for the case of a fibrous
composite with orthotropic components are used as the fundamental relations. The fracture criterion is given as a limit value
of the intensity of average shear stresses occurring in the undamaged part of the material, which is assumed to be a random
function of coordinates and is described by the Weibull distribution. Based on an analytical and numerical approach, the algorithm
for determining the nonlinear deformation properties of such a material is constructed. The nonlinearity of composite deformations
is caused by the accumulation of microdamages in the fibers. By using a numerical solution, the nonlinear stress–strain diagrams
for an orthotropic composite in uniaxial tension are obtained.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 45, No. 1, pp. 17–30, January–February, 2009. 相似文献
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A. Lagzdins 《Mechanics of Composite Materials》2001,37(5-6):381-394
A calculation model is proposed for unidirectionally reinforced elastoplastic composites capable of gradually accumulating disperse microdamages under loading. The composite is assumed to be a homogeneous transversely isotropic solid. To describe its elastoplastic behavior, an incremental plasticity theory with a nonlinear combined hardening mechanism is invoked. At each point of the solid, its damage is characterized by a centrally symmetric scalar function on a unit sphere. This function is approximated by a fourth-rank tensor, which is used for describing the degradation of the elastic properties of the solid due to the accumulation of disperse microdamages. It is shown how to determine, using the known experimental data, all material constants appearing in the theoretical relations suggested. 相似文献
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