Modeling of scattered damage accumulation kinetics under combined stress

Bobyr, N. I.; Халимон, А. П.; Bondarets, Oleksandr

doi:10.1007/s11223-012-9344-y

Cited by 8 publications

(7 citation statements)

References 12 publications

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“…The value of the damage parameter averaged over all directions in the sheets, increases with an increase in the number of AB cycles to 5 in accordance with relations (12) and (13). Anisotropy of the both elastic modulus and damage parameters takes place, both in the original sheet processed according to the mode ΙΙ and after alternating bending (Tables 4-6).…”

Section: Eejp 1 (2020)supporting

confidence: 69%

“…The effective elastic properties remained orthotropic with good accuracy even with a high density of interacting cracks, as was shown by the micromechanical analysis [7]. As it was experimentally shown in [12], an assessment of the damage parameter based on the Lemaitre equivalent deformation model [9] gives higher values of the damage parameter compared to models based on the equivalent elastic energy pattern [10,11] and which give very similar numerical values. Therefore, the assessment of the damage parameter ω according to (3) is the best in comparison with (2) when analyzing the anisotropy of damage to sheet material [12].…”

mentioning

confidence: 79%

“…At the same time, the lack of sufficient physical justification of the models (kinetic equations) gives rise to ambiguity in experimental estimates of the damage parameter ω, depending on the method of its determination for the same sample of the material under study [12]. The relationship between the damage parameter and the change in the structural state and texture under external influences can still be obtained only on the basis of the corresponding correlation and regression analysis.…”

mentioning

confidence: 99%

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Effect of Kind of Deformation on Young's Modulus, Damage Parameter, Texture and Structure of Alloy Mg – 5% Li (wt)

Usov

Brokmeier²,

Shkatulyak

et al. 2020

EEJP

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Effect of deformation by extrusion, rolling after extrusion (in combination with annealing and changing the rolling direction), and subsequent alternating bending (AB) with the number of cycles 0.5, 1, 3, and 5 on the elastic modulus (E), damage accumulation parameter (damage parameter ω), crystallographic texture, and substructure parameters of the binary Mg-5%Li alloy have been studied. The damage parameter (0 ≤ ω ≤ 1), which is interpreted as the relative reduction in the effective load-bearing cross-sectional area due to damage accumulation, was found by the change in the elastic modulus after various above types of deformation. At this, we used to compare equivalent deformation and equivalent elastic energy models. The substructure parameters (crystalline domains sizes D, lattice distortion ε, dislocation density ρ) were estimated by analyzing the physical broadening of the lines diffraction on the crystal lattice of studied alloy of the penetrating hard X-ray synchrotron radiation. It was found that in the studied alloy, sheet forms a texture, at which the hexagonal prism axis is 90° deviated from the normal direction (ND) to the sheet up to transverse direction (TD) after extrusion of the ingot at 350°C in combination with its further rolling in the direction of extrusion axis (rolling direction RD) to a thickness of 4.5 mm and annealing at 350°C after each pass. At this the crystallographic directions and coincide with RD. The texture, at which the hexagonal prism axis is deviated from ND to TD by angles ranging from 15 to 70° (unlike from texture of basal type of the pure magnesium) is formed after further rolling of studied alloy to a thickness of 1 mm with the changing of the RD on 90° in combination with annealing at 350°C after each pass. The crystallographic direction coincides with RD. The anisotropy of above mentioned characteristics was found. Correlation and regression analysis showed that the anisotropy and the values of E, D, ε, and ρ, are decreased, and the values of ω are increased with an increase of alternating bend cycles’ number. It is shown that changes in the above characteristics are mainly due to the crystallographic texture formed during thermomechanical processing and subsequent alternating bending of Mg-5%Li alloy sheets, which is confirmed by data of correlation and regression analysis.

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Section: Eejp 1 (2020)supporting

confidence: 69%

mentioning

confidence: 79%

mentioning

confidence: 99%

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Effect of Kind of Deformation on Young's Modulus, Damage Parameter, Texture and Structure of Alloy Mg – 5% Li (wt)

Usov

Brokmeier²,

Shkatulyak

et al. 2020

EEJP

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show abstract

“…Even with a high density of interacting cracks, the effective elastic properties remained orthotropic with good accuracy, as shown by Kachanov [10] by means of micromechanical analysis. In [15], it was experimentally shown that the assessment of the damageability parameter based on the Lemaitre equivalent deformation model [12] gives higher values of the damage parameter compared to models based on the equivalent elastic energy model [13,14], and which give close numerical values. Therefore, the estimate of the damage parameter ω according to (3) is the best in comparison with (2) when analyzing the anisotropy of damage to sheet material [15].…”

Section: Materials and Research Methodsmentioning

confidence: 99%

Kearns texture parameters, mechanical properties and damageability of titanium sheet after alternating bending

Usov

Shkatulyak

Savchuk

et al. 2021

Phys. Chem. Solid St.

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This work aims to determine the Kearns texture parameters and evaluate on their basis the elastic moduli, mechanical properties (ultimate tensile strength, conditional yield stress), as well as damageability parameters of the sheets commercial titanium (CT-grade 1: 0.04% Fe; 0.015% C; 0.05% N 0.05% c; 0.009% H) as delivered after rolling and annealing at 840°C (original sheet) and further alternating bending (AB) in the amount of 0.5; 1, 3 and 5 cycles. Damageability parameters characterizing damage accumulation were determined from the elastic modulus change after the above-mentioned number of AB cycles relative to the values of the elastic modulus in different directions of the original sheet of the studied titanium. The elastic constants of the single crystal and the Kearns texture parameters were used to estimate the elastic modulus in the rolling direction (RD) and transverse direction (TD) of the original sheet, and sheets after an above number of AB cycles. The deviation of the calculated and experimental values of the elastic modulus did not exceed 5%. The deviation of the calculated and experimental values of the ultimate tensile strength and yield stress in the RD and TD both in the initial state and after the corresponding number cycles of the AB did not exceed 10%.

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“…Для металічних КМ встановлено, що залежність параметру пошкоджуваності від коефіцієнту анізотропії (рис. 5) практично не залежить від рівня пружно-пластичного деформування [23]. Це дає можливість звести кількість досліджень до визначення кінетики накопичення розсіяних руйнувань в КМ тільки для одновісного розтягу зразків в напрямку однієї із вісей ортотропії.…”

Section: результати дослідженьunclassified

Criterion of the limit state of composites materials

Bobyr¹

2022

Mech. Adv. Technol.

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The work proposes and substantiates a type of phenomenal criterion of composite material destruction at the stage of macro crack origination. It considers damageability and two mechanisms of destruction: tearing and slice. It describes that as parameter of damageability it can be taken specific energy of extra stresses or specific energy of diffusion. For proportionate and complex processes of metallic materials loading they result equally in practice. Methodologies of respective energetic parameters search are described. It is set threshold value of stress in the element of construction during the reach of it it is necessary to consider an accumulation of damage. It is described the methodology that describes interconnection between anisotropy factors and components of damage tensor.

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Modeling of scattered damage accumulation kinetics under combined stress

Cited by 8 publications

References 12 publications

Effect of Kind of Deformation on Young's Modulus, Damage Parameter, Texture and Structure of Alloy Mg – 5% Li (wt)

Effect of Kind of Deformation on Young's Modulus, Damage Parameter, Texture and Structure of Alloy Mg – 5% Li (wt)

Kearns texture parameters, mechanical properties and damageability of titanium sheet after alternating bending

Criterion of the limit state of composites materials

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