Mechanism of Failure of Polymers

Бартенев, Г. М.; Zuyev, Yu.S.

doi:10.1016/b978-0-08-003110-1.50007-8

Cited by 15 publications

(24 citation statements)

References 8 publications

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“…According to the well-known experimental data from [3,6,10], inorganic glass suffers brittle fracture in a fairly broad temperature range. Therefore, we can assume that the fracture of glass, at least in the last stage, occurs as a result of crack propagation.…”

Section: Statistical Model Of Fracture Of Glassmentioning

confidence: 99%

“…In [3,6,10], it is shown that the influence of surface defects on the strength of glass is predominant. In commercial types of glass, the technology of their manufacturing and treatment leads to the formation of surface scratchlike defects.…”

Section: Statistical Model Of Fracture Of Glassmentioning

confidence: 99%

“…Preparation of the Specimens. According to [3,6,10], the influence of the surface of glass on its strength is predominant. To study the characteristics of strength in the case of simple uniform plane stressed state under the conditions of uniform tension of specimens, we analyzed the strength of circular glass disks (thin glass plates) loaded by the method of axially symmetric bending.…”

Section: Introductionmentioning

confidence: 99%

“…In the literature, main attention is given to the analysis of the dependence of the time interval τ from the time of application of loading to fracture on the level of stresses σ, i.e., to the service life of a brittle material. In [1][2][3][4][5][6], the function of service life at a constant temperature is extrapolated by the following exponential dependence: τ σ = − Ae c .…”

Section: Introductionmentioning

confidence: 99%

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On the Statistical Theory of Long-Term Strength of Glass

Margolin

Martynova²,

Osadchuk³

et al. 2005

Strength Mater

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We present new methods for the evaluation of the statistical parameters of long-term strength of glass and describe the procedure of preparation of specimens (glass disks) for testing, the method of loading, and the experimental procedure. The statistical model of fracture of glass is presented and the conclusions concerning the evaluation of the parameters of strength are made.Keywords: long-term strength, reliability of glass disks, logarithmically normal distribution function of service life, uniform tension of the surface of glass disks.Introduction. Thin-walled glass products are extensively used in contemporary instrument making. In the process of manufacturing and long-term operation of these products, the action of various loads leads to the formation of significant mechanical stresses resulting, in some cases, in their fracture. Therefore, the necessity of development of new methods aimed at the evaluation of reliability of these structures (probability of the absence of fracture) is a fairly urgent problem. To develop procedures of this sort, it is necessary to study the characteristics of long-term strength of glass. In the literature, main attention is given to the analysis of the dependence of the time interval τ from the time of application of loading to fracture on the level of stresses σ, i.e., to the service life of a brittle material. In [1-6], the function of service life at a constant temperature is extrapolated by the following exponential dependence: τ

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Section: Statistical Model Of Fracture Of Glassmentioning

confidence: 99%

Section: Statistical Model Of Fracture Of Glassmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the Statistical Theory of Long-Term Strength of Glass

Margolin

Martynova²,

Osadchuk³

et al. 2005

Strength Mater

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“…In other words, the IR spectroscopic studies also indicate that neither chemical nor other marked types of reactions were detected in the system investigated. The finding that despite the absence of a PABI--filler direct chemical reaction in the system, the activation energy of fracture (breaking) of the filled fibres calculated with file Zhurkov equation [20] increases as the concentration of filler increases is surprising and not yet understood. Structurally sensitive parameter T increases (Table 9), which logically follows from the overall picture of worsening of the orientational and morphological order and the increase in the defectiveness of the system.…”

mentioning

confidence: 91%

Mechanical properties of dispersely filled fibres based on heterocyclic polyamide

et al. 1998

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Physical modification of chemical fibres and filaments by incorporating different fillers in the polymer matrix [ 1,2], including highly disperse inorganic compounds --oxides, salts, metal powders, etc., is widely used. In most cases, modification has the purpose of giving the basic polymer (fibre or filamen0 a number of specific properties: to increase the degree of whiteness, improve the feel, alter the tribological characteristics, increase the flameproofmg, motion properties, resislance to thermooxidative degradation, conductivity, and the ability to absorb different types of radiation. Despite the fact that a large number of publications has been dedicated to problems of physical modification of chemical fibres, a number of questions has virtually not been examined, such as the character of strengthening and breaking of fibres, the reaction of the filler with the polymer macromolecules in the condensed phase and the thermodynamic aspects of this reaction, the specific features of cross-linking, and many others. The question of obtaining high-strength, high-modulus fibres containing highly disperse inorganic fillers has not been investigated at all. We only know that incorporation of up to 35 wt. % barium sulfate or up to 10% lead sulfate in poly-p-phenylene terephthalamide fibres causes the fibres to lose 15-20% of their strength.* We attempted to examine the effect of a highly disperse inorganic filler on the mechanical properties of fibres based on polyamidobenzimidazole (PABI) [3], a heterocyclic polyamide with the following structure of the elementary unit and the character of strengthening and degradation of these fibres and organoplastics made from them on rupture. Powdered oxides (REO) and fluorides (REF) of rare-earth elements of the cerium subgroup (cerium, lanthanum, neodymium, praseodymium) were used as the inorganic fillers. The filler consisted of almost spherical particles from 1 to 10 I.tm in diameter for REF and 5-10 lain in diameter for REO.We know from experience in fabricating ordinary synthetic fibres [2] that the optimum filler particle size in wet spinning is approximately 1 [am. The particles of the disperse filler, which have a high surface energy, usually aggregate both during storage in powdered form and in polymer solutions. This situation can significantly worsen spinning of fibres, resulting in clogging of the spinneret openings. We also know that in most cases, the mechanical strength of the filled fibres and filaments, with all other conditions being equal, is higher the smaller the size of the filler particles. It is thus obvious that the smaller the filler particle size is, the greater its total surface area and contact area with the polymer. The contact area of the filler with the polymer and energy of their interaction can also be increased by varying the chemical structure of the surface of the filler by oriented adsorption of surfactants (SF) on it [4]. For this reason, one of the stages of fabrication of filled fibres in our case was dispersion of the oxides or salts of ...

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Deformation of Poly(dimethylsiloxane) Oligomers under Uniaxial Tension: Quantum Chemical View

et al. 1999

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The response of a silicone polymer fragment to external stresses is considered in terms of a mechanochemical reaction. The quantum chemical realization of the approach is based on a coordinate-of-reaction concept for the purpose of introducing a mechanochemical internal coordinate (MIC) that specifies a deformational mode. The related force of response is calculated as the energy gradient along the MIC, while the atomic configuration is optimized over all of the other coordinates under the MIC constant-pitch elongation. The approach is applied to a set of linear silicone oligomers Si n with n = 4, 5, and 10 subjected to uniaxial tension, followed by the molecule breaking and a postfracture relaxation. Three stages of deformation, differing by structural transformation, have been detected. The observed peculiarities of the oligomer mechanical behavior are well attributed to the characteristic modes of vibrational spectra. The oligomer strength and the related Young's moduli are obtained. A cooperative radical-driven mechanism of silicone polymer fracture is suggested.

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Mechanism of Failure of Polymers

Cited by 15 publications

References 8 publications

On the Statistical Theory of Long-Term Strength of Glass

On the Statistical Theory of Long-Term Strength of Glass

Mechanical properties of dispersely filled fibres based on heterocyclic polyamide

Deformation of Poly(dimethylsiloxane) Oligomers under Uniaxial Tension: Quantum Chemical View

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