Mesomechanics - The microstructure-mechanics connection

Haritos, George; Hager, Joseph W.; Amos, A. K.; Salkind, Michael J.; Wang, A.

doi:10.2514/6.1987-726

Cited by 6 publications

(7 citation statements)

References 7 publications

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“…According to Haritos et al (1988) and Vil'deman et al (1997), in order to allow for the influence of the surrounding material layers and to reproduce more accurately the stress-strain state for each loaded mesocell, a buffer layer was placed around it. The buffer layer was composed of eight identical homogeneous and isotropic cells, their sizes being consistent with that of the central mesocell ( Figure 4).…”

Section: Materials and Investigation Proceduresmentioning

confidence: 99%

“…The computer simulation was performed on the basis of the two-level structural-phenomenological approach (Haritos et al, 1988;Vil'deman et al, 1997) connecting problem solutions on different scaling levels. According to this approach, on the first (macroscale) level the material is considered to be a homogeneous isotropic strengthening medium with experimentally determined volume-averaged properties.…”

Section: Materials and Investigation Proceduresmentioning

confidence: 99%

“…Mesomechanics as a research area was formulated on the basis of a multilevel approach, with the simultaneous application of the principles of continuum mechanics and material science analysis (Haritos et al, 1988;Panin et al, 1985Panin et al, , 1998. Experimental investigations and numerical simulation of the plastic deformation of structurally heterogeneous materials with a clearly specified microstructure are successfully pursued within this research area (Balokhonov et al, 2006;Makarov, 1998;Panin et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Hierarchical simulation of plastic deformation and fracture of complexly alloyed brass

Смирнов

Myasnikova

Пугачева

2015

International Journal of Damage Mechanics

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The paper deals with simulating plastic deformation and fracture of the constituents of complexly alloyed brass in upsetting under the plane strain state in view of their geometry, mechanical properties and the stress state during deformation. The peculiarities of the formation of a net of localised strain bands are discussed. It is demonstrated that brass deformation is mainly due to the malleable matrix and that it is brittle silicide particles that fail. Stress non-uniformity in silicides has been detected with the presence of both tensile and compressive normal stress areas in them. Stress stiffness coefficient distribution functions have been constructed, and a relationship between the ultimate strains of brittle silicide particles in the soft phase and the stress stiffness coefficient has been defined. The dependence has been used to simulate damage accumulation in the silicides before fracture during upsetting under plane strain. The probability of silicide fracture under deformation is shown to be reducible due to the use of stress states offering a high level of macroscopic compressive stresses -high enough to minimise zones with prevailing tensile stresses in the silicides.

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Section: Materials and Investigation Proceduresmentioning

confidence: 99%

Section: Materials and Investigation Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hierarchical simulation of plastic deformation and fracture of complexly alloyed brass

Смирнов

Myasnikova

Пугачева

2015

International Journal of Damage Mechanics

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“…According to meso mechanics, the meso structures of a material refer to the subtle structures visible through optical or conventional electron microscopy with scales ranging from 10 nm to the millimetre range [26,27], which has an important significance on the quantitative research of the macroscopic physical properties. During the SEM scans, a rectangular region (4.5 mm Â 2.2 mm) at the upper-right corner of the surface of coal sample A along the cross line was set to the full-width scanning area, as shown in Fig.…”

Section: Characteristics Of Meso Structures In Coalmentioning

confidence: 99%

Experimental meso scale study on the distribution and evolution of methane adsorption in coal

Zhou

Feng

Zhao

et al. 2017

Applied Thermal Engineering

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“…The research is based on the concepts of probabilistic mesomechanics [22], which provides the relationships between the microstructural material properties and noncontinuum mechanics [23]. In this research, the mesoelements are defined as the individual grains of a polycrystalline aggregate.…”

Section: Probabilistic Micromechanicsmentioning

confidence: 99%

Using Probabilistic Microstructural Methods to Predict the Fatigue Response of a Simple Laboratory Specimen

Tryon¹

2004

Engineering Design Reliability Handbook

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For the purpose of this chapter, fatigue is defined as the entire range of damage-accumulation sequences, from crack nucleation of the initially unflawed bar to final fast fracture. Background Various Stages of FatigueCurrent fatigue-life prediction methods in metallic components consider three stages: crack initiation, long-crack propagation, and final fracture. Long-crack propagation and final fracture are the stages of damage accumulation that are well characterized using linear elastic or elastic-plastic fracture mechanics. Crack initiation is the early stage of damage accumulation where small cracks (cracks with depths less than several grain diameters) have been observed to deviate significantly from predicted long-crack fracture mechanics behavior [1]. The deviation is attributed to the heterogeneous media in which small cracks evolve [2].The crack-initiation stage can be broken down into two phases: crack nucleation and small-crack growth. Crack nucleation is the locally complex process of crack formation on the microstructural scale. Crack nucleation is characterized by smooth fracture surfaces at angles inclined to the loading direction. This type of failure is indicative of shear stress Mode II (sliding mode) fracture. Although loading has been shown to affect the nucleation size [3,4], experimental evidence suggest that the nucleation size is on the order of the grain size [5][6][7].Small-crack growth is characterized by fracture-surface striations perpendicular to the loading direction. This type of failure is indicative of tensile stress Mode I (opening mode) fracture. The behavior of small cracks tends to transition to linear or elastic-plastic fracture mechanics behavior when the crack depth reaches about ten mean grain diameters [8]. Crack nucleation and small-crack growth must be modeled separately because different mechanisms control each phase. The relative importance of the crack-nucleation stage on overall fatigue life depends on several factors. Materials that exhibit a strong preference for planar slip show a strong correlation between the crack causing final fracture and the earliest nucleated cracks [9]. Materials that prefer cross slip showed almost no correlation between the crack causing final fracture and the earliest nucleated cracks [9]. The relative importance of the crack nucleation may also depend on the loading condition. If the loading is relatively low (high-cycle fatigue), the majority of life will be spent in the nucleation of a crack. If the loading is high (low-cycle fatigue), cracks may nucleate early and spend the remainder of the fatigue life in the crack-growth stages. However, high-strength materials have been shown to spend the majority of fatigue life in the crack-nucleation stage, even during low-cycle fatigue [10]. Scatter in Fatigue LifeThe coefficient of variation (COV) of fatigue-life tests range widely, depending on the material alloy and load level. Even for well-controlled laboratory tests of annealed smooth specimens at room temperature, the COV varies fro...

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Mesomechanics - The microstructure-mechanics connection

Cited by 6 publications

References 7 publications

Hierarchical simulation of plastic deformation and fracture of complexly alloyed brass

Hierarchical simulation of plastic deformation and fracture of complexly alloyed brass

Experimental meso scale study on the distribution and evolution of methane adsorption in coal

Using Probabilistic Microstructural Methods to Predict the Fatigue Response of a Simple Laboratory Specimen

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