The influence of mechanical and microstructural properties on the rate-dependent fracture strength of ceramics in uniaxial compression

Holland, Chance C.; McMeeking, Robert M.

doi:10.1016/j.ijimpeng.2015.02.007

Cited by 29 publications

(14 citation statements)

References 38 publications

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“…The simulated compressive strength is dramatically sensitive to the imposed strain rate especially in dynamic strain rate ranges. This is in agreement with a great number of experiments indicating that compressive rock strength is sensitive to the applied loading rates, particularly in dynamic loading range [18].…”

Section: Figure 6 the Stress-strain Curves Simulated Under Various Isupporting

confidence: 92%

“…When the rock materials are subjected to continuous compressive loading, local stress concentration (stress intensity factor) (SIF), at the crack tips increases. At the specific moment, the SIF at crack tips reaches the rock material fracture toughness level, so the tensile wing-cracks with length of propagate from the tips of a pre-existing micro-cracks [18]. This phenomenon is called wing-crack nucleation as shown in Figure 3.…”

Section: Theory and Backgroundmentioning

confidence: 99%

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Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Ahmadi

Molladavoodi

2018

Civ Eng J

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A micromechanical constitutive damage model accounting for micro-crack interactions was developed for brittle failure of rock materials under compressive dynamic loading. The proposed model incorporates pre-existing flaws and microcracks that have same size with specific orientation. Frictional sliding on micro-cracks leading to inelastic deformation is very influential mechanism resulting in damage occurrence due to nucleation of wing-crack from both sides of pre-existing micro-cracks. Several homogenization schemes including dilute, Mori-Tanaka, self-consistence, Ponte-Castandea & Willis are usually implemented for up-scaling of micro-cracks interactions. In this study the Self-Consistent homogenization Scheme (SCS) was used in the developed damage model in which each micro-crack inside the elliptical inclusion surrounded by homogenized matrix experiences a stress field different from that acts on isolated cracks. Therefore, the difference between global stresses acting on rock material and local stresses experienced by micro-crack inside inclusion yields stress intensity factor (SIF) at the cracks tips which are utilized in the formulation of the dynamic crack growth criterion. Also the damage parameter was defined in term of crack density parameter. The developed model was programmed and used as a separate and new constitutive model in the commercial finite difference software (FLAC). The dynamic uniaxial compressive strength test of a brittle rock was simulated numerically and the simulated stress-strain curves under different imposed strain rates were compared each other. The analysis results show a very good strain rate dependency especially in peak and post-elastic region. The proposed model predicts a macroscopic stress-strain relation and a peak stress (compressive strength) with an associated transition strain rate beyond which the compressive strength of the material becomes highly strain rate sensitive. Also the damage growth process was studied by using the proposed micromechanical damage model and scale law was plotted to distinguish the dynamic and quasi-dynamic loading boundary. Results also show that as the applied strain rate increases, the simulated peak strength increases and the damage evolution becomes slower with strain increment.

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Section: Figure 6 the Stress-strain Curves Simulated Under Various Isupporting

confidence: 92%

Section: Theory and Backgroundmentioning

confidence: 99%

Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Ahmadi

Molladavoodi

2018

Civ Eng J

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“…Fracture under tension at high strain rate is caused mainly by increasing the sizes of penny-shaped cracks in an inter-voids polycrystalline ceramics volume. Penny-shaped cracks can be created as the circular pore flaws in a vicinity of various stress concentrators at the microscopic level such as pores, inclusions of phases [6][7][8][9].…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…The use of nanopowders of ultra-high temperature compounds can reduce the temperature of the pressing and reduce the size of pores in ceramics. Results of multilevel modeling show that the fracture of nanostructured ceramic materials under dynamic loading can be quasi-brittle [5][6][7][8][9]. Dynamic fracture toughness of nanostructured ultra-high temperature ceramic materials is higher compared with coarse-crystalline counterparts.…”

Section: Introductionmentioning

confidence: 99%

Fracture mechanisms of zirconium diboride ultra-high temperature ceramics under pulse loading

Skripnyak¹,

Bragov²,

Skripnyak³

et al. 2017

AIP Conference Proceedings

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Influence of grain size distribution on the mechanical behavior of light alloys in wide range of strain rates AIP Conference Proceedings 1793, 110001 (2017) bragov@mech.unn.ru, c) skrp2006@yandex.ru.Abstract. Mechanisms of failure in ultra-high temperature ceramics (UHTC) based on zirconium diboride under pulse loading were studied experimentally by the method of SHPB and theoretically. The obtained experimental and numerical data are evidence of the quasi-brittle fracture character of nanostructured zirconium diboride ceramics under compression and tension at high strain rates and the room temperature. Damage of nanostructured porous zirconium diboride-based UHTC can be formed under stress pulse amplitude below the Hugoniot elastic limit. Fracture of nanostructured ultra-high temperature ceramics under pulse and shock-wave loadings is provided by fast processes of intercrystalline brittle fracture and relatively slow processes of quasi-brittle failure via growth and coalescence of microcracks.

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“…To study the dynamic strength of UHTC nanocomposites we used the method of multiscale simulation [6][7][8]. The calculated values of residual stresses were used in the simulation of loading of the elementary volume of ZrB 2 matrix nanocomposite under shock wave loadings.…”

Section: Model Of Mechanical Behavior Of Nanocompositesmentioning

confidence: 99%

Brittle or Quasi-Brittle Fracture of Ceramic Nanocomposites Under Dynamic Loading

Skripnyak¹,

Skripnyak²,

Skripnyak³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Multiscale computer simulation was used for simulation of the damage nucleation and fracture of ZrB nanocomposites under dynamic loading. The aim of research was the study transition from brittle to quasibrittle fracture of nanocomposites under dynamic loading. It was shown that isolated microand mesoscale cracks can be nucleate in ceramic nanocomposites near voids under stress pulse amplitude less than the Hugoniot elastic limit. The critical fracture stress on mesoscale level depends not only on relative volumes of voids and particles concentration, but also sizes of corresponding structure elements. Results of simulation have shown the Hugoniot elastic limit and ceramics damage kinetics under dynamic loading depends on a volume concentration of nano-particles and nano-voids clusters.

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The influence of mechanical and microstructural properties on the rate-dependent fracture strength of ceramics in uniaxial compression

Cited by 29 publications

References 38 publications

Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Fracture mechanisms of zirconium diboride ultra-high temperature ceramics under pulse loading

Brittle or Quasi-Brittle Fracture of Ceramic Nanocomposites Under Dynamic Loading

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