On possible causes of brittle fracture

Ivanov, A. G.

doi:10.1007/bf00853495

Cited by 6 publications

(2 citation statements)

References 7 publications

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“…A sample is loaded by a plane shock wave, and the passage of the leading edge leads to the one-dimensional compression of the material and its heating [7], which is identical to the physical processes occurring during jet penetration into a target. For some value of the dynamic compression, the material undergoes irreversible structural changes which cause the same irreversible changes in the strength properties of the material.…”

Section: General Propositionsmentioning

confidence: 99%

Resistance of the medium during high-velocity penetration of long rods and shaped-charge jets

Savenkov

Meshcheryakov

Divakov

et al. 2010

Combust Explos Shock Waves

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We consider the high-velocity penetration of long rods and shaped-charge jets into semi-infinite targets with initial impact velocities of 2-4 km/sec. At these velocities, the mechanical characteristics of the target materials makes a great contribution to the final parameters of the process: penetration depth and critical velocity of the impactor (jet). The dynamic compressive stability threshold of the material, obtained in experiments with uniaxial dynamic loading of flat targets, is proposed as a parameter that determines the properties of the target in the penetration process.

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Section: General Propositionsmentioning

confidence: 99%

Resistance of the medium during high-velocity penetration of long rods and shaped-charge jets

Savenkov

Meshcheryakov

Divakov

et al. 2010

Combust Explos Shock Waves

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show abstract

“…In the determination of the force and energetic criteria for spall processes (spall strength σ fr and specific (per unit surface area) spall work λ fr ) in experiments on spall fracture of materials, it is assumed that strictly onedimensional regular deformation occurs which is equivalent to the ideal restraining of material [15]. However, fractal curves are geometrically chaotic curves; therefore, in the case of a fractal spall crack contour, deformation motions of the material are of random chaotic nature.…”

mentioning

confidence: 99%

Relationship between spall characteristics and the dimension of fractal fracture structures

Барахтин

Savenkov²

2009

J Appl Mech Tech Phy

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The effect of the fractality of a fracture surface and spall contour on the characteristics [fracture time (strength) and spall strength] of the loaded material is studied. It is shown that an increase in the fractal dimensions of the spall contour leads to an increase in the material strength parameter in the tensile wave and spall strength, whereas an increase in the fractal dimension of the fracture surface leads to a decrease in the spall strength. As an example, the spall strength is calculated taking into account the fractality of the fracture surface for Sp. 28 steel. Introduction.As is known, the dynamic (in particular, spall) fracture of materials is a multiphase kinetic process based on the polyscale evolution of internal material defects. At each scale level, the nature and duration of elementary events of structural changes are different and interrelated. In addition, the initiation and development of defects at different stages is possible, i.e., the formation of macrodefects can be accompanied by the initiation of submicrodefects, their coalescence with the formation of microdefects, etc. In this case, the indicated processes influence each other. From the aforesaid, it follows that constructing a mathematical multilevel model of dynamic (spall) fracture taking into account the multifactor nature of the process (description of each level, determination of the relations between the physical processes at each level, and determination of the influence of the processes occurring at all levels on the processes occurring at a chosen level) is a difficult problem. There are a number of models describing various features of material behavior under dynamic (spall) fracture conditions. Wide use has been made of models that include only two fracture stages (microlevel and macrolevel) or employ only statistical methods for describing the initiation and development of defects [1].Recently, models has been developed that take into account the discrete nature of a deformable medium, which is treated as a dissipative system, whose evolutions leads to the occurrence of fractal structures capable of self-similar propagation resulting in global fracture upon reaching some critical conditions [2][3][4][5].The purpose of the present work is to establish relations among the strength t fr , the spall strength σ fr of the material, and the fractal parameters of the fracture surface formed during shock-induced spall fracture.Experimental Technique. Disks-shaped targets 52 mm in diameter and 5-10 mm thick made of steels of various classes were loaded by a flat impactor using a pneumatic gun at velocities V 0 = 200-650 m/sec.The tested targets were studied with a SEM 535 scanning electron microscope. The fractal dimensions of the spall contour and the size distribution of shear and spall regions (defects) were determined by digitization and statistical processing of electron photomicrographs of vertical sections of the fracture surface of the targets at magnifications over a wide range (from 10 to 5 · 10 3 ).Experimental Resu...

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Shock-wave failure of a wound glass-fiber-reinforced plastic in different directions

Ivanov¹,

Syrunin²,

Luchinin³

1992

J Appl Mech Tech Phys

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On possible causes of brittle fracture

Cited by 6 publications

References 7 publications

Resistance of the medium during high-velocity penetration of long rods and shaped-charge jets

Resistance of the medium during high-velocity penetration of long rods and shaped-charge jets

Relationship between spall characteristics and the dimension of fractal fracture structures

Shock-wave failure of a wound glass-fiber-reinforced plastic in different directions

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