Статті в журналах: "Micromechanic model"

1

Altus, E., and A. Herszage. "A two-dimensional micromechanic fatigue model." Mechanics of Materials 20, no. 3 (May 1995): 209–23. http://dx.doi.org/10.1016/0167-6636(94)00057-3.

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2

Altus, Eli, and Ella Bergerson. "Fatigue of hybrid composites by a cohesive micromechanic model." Mechanics of Materials 12, no. 3-4 (November 1991): 219–28. http://dx.doi.org/10.1016/0167-6636(91)90019-v.

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3

Altus, E. "A cohesive micromechanic fatigue model. Part I: Basic mechanisms." Mechanics of Materials 11, no. 4 (July 1991): 271–80. http://dx.doi.org/10.1016/0167-6636(91)90027-w.

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4

Altus, E. "A cohesive micromechanic fatigue model. Part II: Fatigue-creep interaction and Goodman diagram." Mechanics of Materials 11, no. 4 (July 1991): 281–93. http://dx.doi.org/10.1016/0167-6636(91)90028-x.

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5

Khen, R., and E. Altus. "Effect of static mode on fatigue crack growth by a unified micromechanic model." Mechanics of Materials 21, no. 3 (October 1995): 169–89. http://dx.doi.org/10.1016/0167-6636(95)00011-9.

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6

Placidi, Luca, Francesco dell’Isola, Abdou Kandalaft, Raimondo Luciano, Carmelo Majorana, and Anil Misra. "A granular micromechanic-based model for Ultra High Performance Fiber-Reinforced Concrete (UHP FRC)." International Journal of Solids and Structures 297 (July 2024): 112844. http://dx.doi.org/10.1016/j.ijsolstr.2024.112844.

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7

Ghasemi, Ahmad Reza, Mohammad Mohammadi Fesharaki, and Masood Mohandes. "Three-phase micromechanical analysis of residual stresses in reinforced fiber by carbon nanotubes." Journal of Composite Materials 51, no. 12 (September 20, 2016): 1783–94. http://dx.doi.org/10.1177/0021998316669854.

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In this study, circular disk model and cylinder theory for two dimension (2D) and three dimension (3D), respectively, have been used to determine residual stresses in three-phase representative volume element. The representative volume element is consisting of three phases: carbon fiber, carbon nanotubes, and polymer matrix, that carbon fiber is reinforced by carbon nanotube using electrophoresis method. Initially, the residual stresses analysis of two-phase representative volume element has been implemented. The two-phase representative volume element has been divided to carbon fiber and matrix phases with different volume fractions. In the three-phase representative volume element, although the volume fraction of carbon fiber is constant and equal to 60%, the volume fractions of carbon nanotubes for various cases are different as 0%, 1%, 2%, 3%, 4%, and 5%. Also, there are two different methods to reinforce the fiber according to different coefficients of thermal expansion of the carbon fiber and carbon nanotube in two longitudinal and transverse directions; carbon nanotubes are placed on carbon fiber either parallel or around it like a ring. Subsequently, finite element method and circular disk model have been used for analyzing micromechanic of the residual stresses for 2D and then the results of stress invariant obtained by the finite element method have been compared with the circular disk model. Moreover, for 3D model, the finite element method and cylinder theory have been utilized for micromechanical analysis of the residual stresses and the results of stress invariant obtained by them, have been compared with each other. Results of the finite element method and analytical model have good agreement in 2D and 3D models.

8

Hernández, M. G., J. J. Anaya, L. G. Ullate, and A. Ibañez. "Formulation of a new micromechanic model of three phases for ultrasonic characterization of cement-based materials." Cement and Concrete Research 36, no. 4 (April 2006): 609–16. http://dx.doi.org/10.1016/j.cemconres.2004.07.017.

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9

Zhang, Chuangye, Wenyong Liu, Chong Shi, Shaobin Hu, and Jin Zhang. "Experimental Investigation and Micromechanical Modeling of Hard Rock in Protective Seam Considering Damage–Friction Coupling Effect." Sustainability 14, no. 23 (December 6, 2022): 16296. http://dx.doi.org/10.3390/su142316296.

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The hard rock in the protective coal seam of the Pingdingshan Mine in China is a typical quasi-brittle material exhibiting complex mechanical characteristics. According to available research on the mechanical property, the inelastic deformation and development of damage are considered related with crack initiation and propagation, which are main causes of the material degradation. In the present study, an original experimental investigation on the rock sample of the Pingdingshan coal mine is firstly carried out to obtain the basic mechanical responses in a conventional triaxial compression test. Based on the homogenization method and thermodynamic theory, a damage–friction coupled model is proposed to simulate the non-linear mechanical behavior. In the framework of micromechanics, the hard rock in a protective coal seam is viewed as a heterogeneous material composed of a homogeneous solid matrix and a large number of randomly distributed microcracks, leading to a Representative Elementary Volume (REV), i.e., the matrix–cracks system. By the use of the Mori–Tanaka homogenization scheme, the effective elastic properties of cracked material are obtained within the framework of micromechanics. The expression of free energy on the characteristic unitary is derived by homogenization methods and the pairwise thermodynamic forces associated with the inelastic strain and damage variables. The local stress tensor is decomposed to hydrostatic and deviatoric parts, and the effective tangent stiffness tensor is derived by considering both the plastic yield law and a specific damage criterion. The associated generalized Coulomb friction criterion and damage criterion are introduced to describe the evolution of inelastic strain and damage, respectively. Prepeak and postpeak triaxial response analysis is carried out by coupled damage–friction analysis to obtain analytical expressions for rock strength and to clarify the basic characteristics of the damage resistance function. Finally, by the use of the returning mapping procedure, the proposed damage–friction constitutive model is applied to simulate the deformation of Pingdingshan hard rock in triaxial compression with respect to different confining pressures. It is observed that the numerical results are in good agreement with the experimental data, which can verify the accuracy and show the obvious advantages of the micromechanic-based model.

10

Mahesh, C., K. Govindarajulu, and V. Balakrishna Murthy. "Simulation-based verification of homogenization approach in predicting effective thermal conductivities of wavy orthotropic fiber composite." International Journal of Computational Materials Science and Engineering 08, no. 04 (September 24, 2019): 1950015. http://dx.doi.org/10.1142/s2047684119500155.

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In this work, applicability of homogenization approach is verified with the micromechanics approach by considering wavy orthotropic fiber composite. Thermal conductivities of [Formula: see text]-300 orthotropic wavy fiber composite are determined for micromechanical model and compared with the results obtained by two stage homogenized model over volume fraction ranging from 0.1 to 0.6. Also, a methodology is suggested for reducing percentage deviation between homogenization and micromechanical approaches. Effect of debond on the thermal conductivities of wavy orthotrophic fiber composite is studied and compared with perfectly aligned fiber composite for different volume fraction. It is observed that results obtained by the homogenization approach are in good agreement with the results obtained through micromechanics approach. Maximum percentage deviation between homogenized and micromechanics models is 2.13%.

11

Zhao, Xiaoyu, Fei Guo, Beibei Li, Guannan Wang, and Jinrui Ye. "Multiscale Simulation on the Thermal Response of Woven Composites with Hollow Reinforcements." Nanomaterials 12, no. 8 (April 8, 2022): 1276. http://dx.doi.org/10.3390/nano12081276.

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In this paper, we established a progressive multiscale model for a plain-woven composite with hollow microfibers and beads and investigated the general conductive thermal response. Micromechanic techniques were employed to predict the effective conductivity coefficients of the extracted representative volume elements (RVEs) at different scales, which were then transferred to higher scales for progressive homogenization. A structural RVE was finally established to study the influence of microscale parameters, such as phase volume fraction, the thickness of the fibers/beads, etc., on the effective and localized behavior of the composite system It was concluded that the volume fraction of the hollow glass beads (HGBs) and the thickness of the hollow fibers (HFs) had a significant effect on the effective thermal coefficients of the plain-woven composites. Furthermore, it was found that an increasing HGB volume fraction had a more significant effect in reducing the thermal conductivity of composite. The present simulations provide guidance to future experimental testing.

12

Kim, Young Cheol, Hong-Kyu Jang, Geunsu Joo, and Ji Hoon Kim. "A Comparative Study of Micromechanical Analysis Models for Determining the Effective Properties of Out-of-Autoclave Carbon Fiber–Epoxy Composites." Polymers 16, no. 8 (April 14, 2024): 1094. http://dx.doi.org/10.3390/polym16081094.

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This study aims to critically assess different micromechanical analysis models applied to carbon-fiber-reinforced plastic (CFRP) composites, employing micromechanics-based homogenization to accurately predict their effective properties. The paper begins with the simplest Voigt and Reuss models and progresses to more sophisticated micromechanics-based models, including the Mori–Tanaka and Method of Cells (MOC) models. It provides a critical review of the areas in which these micromechanics-based models are effective and analyses of their limitations. The numerical analysis results were confirmed through finite element simulations of the periodic representative volume element (RVE). Furthermore, the effective properties predicted by these micromechanics-based models were validated via experiments conducted on IM7/5320-1 composite material with a fiber volume fraction of 0.62.

13

Chen, Qing, Zhengwu Jiang, Hehua Zhu, J. Woody Ju, Zhiguo Yan, and Yaqiong Wang. "An Improved Micromechanical Framework for Saturated Concrete Repaired by the Electrochemical Deposition Method considering the Imperfect Bonding." Journal of Engineering 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/1894027.

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The interfaces between the deposition products and concrete are not always well bonded when the electrochemical deposition method (EDM) is adopted to repair the deteriorated concrete. To theoretically illustrate the deposition healing process by micromechanics for saturated concrete considering the imperfect interfaces, an improved micromechanical framework with interfacial transition zone (ITZ) is proposed based on our recent studies. In this extension, the imperfect bonding is characterized by the ITZ, whose effects are calculated by modifying the generalized self-consistent model. Meanwhile, new multilevel homogenization schemes are employed to predict the effective properties of repaired concrete considering the ITZ effects. Moreover, modification procedures are presented to reach the properties of repaired concrete with ITZs in the dry state. To demonstrate the feasibility of the proposed micromechanical model, predictions obtained via the proposed micromechanical model are compared with those of the existing models and the experimental data, including results from extreme states during the EDM healing process. Finally, the influences of ITZ and deposition product on the healing effectiveness of EDM are discussed based on the proposed micromechanical model.

14

You, Zhanping, and Qingli Dai. "Review of advances in micromechanical modeling of aggregate–aggregate interactions in asphalt mixtures." Canadian Journal of Civil Engineering 34, no. 2 (February 1, 2007): 239–52. http://dx.doi.org/10.1139/l06-113.

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This paper presents a comprehensive review of the work done by a number of researchers on the modeling of asphalt mixture. Included are some of the earliest models such as those with non-interacting particles (models with and without geometry specified), models with particle interaction, and some new models developed in recent years. The paper focuses on the description and comparison of the most recently developed finite element network model (FENM), a clustered discrete element model (DEM), and a micromechanical finite element model (FEM) used in micromechanical modeling of asphalt mixture. These models consider the complex mixture microstructure and aggregate–aggregate interaction. These models are demonstrated and applications of the advances are provided, where virtual laboratory simulation and laboratory tests were employed. The feasibility of nanotechnology application in asphalt mixture is also briefly discussed.Key words: micromechanical modeling, micromechanics, aggregate–aggregate interaction, finite elements, discrete elements, asphalt mixture.

15

Zhang, H., J. Woody Ju, WL Zhu, and KY Yuan. "A micromechanical model of elastic-damage properties of innovative pothole patching materials featuring high-toughness, low-viscosity nanomolecular resin." International Journal of Damage Mechanics 30, no. 9 (March 17, 2021): 1327–50. http://dx.doi.org/10.1177/10567895211000089.

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Innovative pothole patching materials reinforced with a high-toughness, low-viscosity nanomolecular resin, dicyclopentadiene (DCPD, C10H12), have been experimentally proven to be effective in repairing cracked asphalt pavements and can significantly enhance their durability and service life. In this paper, a three-dimensional micromechanical framework is proposed based on the micromechanics and continuum damage mechanics to predict the effective elastic-damage behaviors of this innovative pothole patching material under the splitting tension test (ASTM D6931). In this micromechanical model, irregular coarse aggregates are approximated and simulated by randomly allocated multi-layer-coated spherical particles in certain representative sizes. Fine aggregates, asphalt binder (PG64-10), cured DCPD (p-DCPD), and air voids are formulated into an isotropic elastic asphalt mastic matrix based on the multilevel homogenization approach. The theoretical micromechanical elastic-damage predictions are then systemically compared with properly designed laboratory experiments as well as three-dimensional finite elements numerical simulations for the innovative pothole patching materials.

16

Lindroos, Matti, Anssi Laukkanen, and Tom Andersson. "Micromechanical modeling of polycrystalline high manganese austenitic steel subjected to abrasive contact." Friction 8, no. 3 (December 19, 2019): 626–42. http://dx.doi.org/10.1007/s40544-019-0315-1.

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AbstractThis study focuses on microstructural and micromechanical modeling of abrasive sliding contacts of wear-resistant Hadfield steel. 3D finite element representation of the microstructure was employed with a crystal plasticity model including dislocation slip, deformation twinning, and their interactions. The results showed that deformation twinning interacting with dislocations had a key role in the surface hardening of the material, and it was also important for the early hardening process of the sub-surface grains beyond the heavily distorted surface grains. The effects of grain orientation and microstructural features were discussed and analyzed according to the micromechanical model to give a perspective to the anisotropy of the material and the feasibility of using micromechanics in virtual material design.

17

Choudhry, RS, Kamran A. Khan, Sohaib Z. Khan, Muhammad A. Khan, and Abid Hassan. "Micromechanical modeling of 8-harness satin weave glass fiber-reinforced composites." Journal of Composite Materials 51, no. 5 (July 28, 2016): 705–20. http://dx.doi.org/10.1177/0021998316649782.

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This study introduces a unit cell-based finite element micromechanical model that accounts for correct post cure fabric geometry, in situ material properties and void content within the composite to accurately predict the effective elastic orthotropic properties of 8-harness satin weave glass fiber-reinforced phenolic composites. The micromechanical model utilizes a correct post cure internal architecture of weave, which was obtained through X-ray microtomography tests. Moreover, it utilizes an analytical expression to update the input material properties to account for in situ effects of resin distribution within yarn (the yarn volume fraction) and void content on yarn and matrix properties. This is generally not considered in modeling approaches available in literature and in particular, it has not been demonstrated before for finite element micromechanics models of 8-harness satin weave composites. The unit cell method is used to obtain the effective responses by applying periodic boundary conditions. The outcome of the analysis based on the proposed model is validated through experiments. After validation, the micromechanical model was further utilized to predict the unknown effective properties of the same composite.

18

Antin, Kim-Niklas, Anssi Laukkanen, Tom Andersson, Danny Smyl, and Pedro Vilaça. "A Multiscale Modelling Approach for Estimating the Effect of Defects in Unidirectional Carbon Fiber Reinforced Polymer Composites." Materials 12, no. 12 (June 12, 2019): 1885. http://dx.doi.org/10.3390/ma12121885.

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A multiscale modelling approach was developed in order to estimate the effect of defects on the strength of unidirectional carbon fiber composites. The work encompasses a micromechanics approach, where the known reinforcement and matrix properties are experimentally verified and a 3D finite element model is meshed directly from micrographs. Boundary conditions for loading the micromechanical model are derived from macroscale finite element simulations of the component in question. Using a microscale model based on the actual microstructure, material parameters and load case allows realistic estimation of the effect of a defect. The modelling approach was tested with a unidirectional carbon fiber composite beam, from which the micromechanical model was created and experimentally validated. The effect of porosity was simulated using a resin-rich area in the microstructure and the results were compared to experimental work on samples containing pores.

19

Bai, JB, JJ Xiong, RA Shenoi, and Q. Wang. "A micromechanical model for predicting biaxial tensile moduli of plain weave fabric composites." Journal of Strain Analysis for Engineering Design 52, no. 5 (May 17, 2017): 333–43. http://dx.doi.org/10.1177/0309324717707858.

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This article presents a new micromechanical model to predict biaxial tensile moduli of plain weave fabric composites by considering the interaction between the orthogonal interlacing strands. The two orthogonal yarns in micromechanical unit cell were idealized as curved beams with a path depicted using sinusoidal shape functions. The biaxial tensile moduli of plain weave fabric composites were derived by means of the minimum total complementary potential energy principle founded on micromechanics. Biaxial tensile tests were conducted on the resin transfer molding–made EW220/5284 plain weave fabric composites at five biaxial loading ratios of 0, 1, 2, 3 and ∞ to validate the new model. Predictions from the new model were compared with experimental data. Good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed model. Using the new model, the biaxial tensile moduli of plain weave fabric composites can be predicted based only on the properties of basic woven fabric.

20

Mamache, Fateh Enouar, Amar Mesbah, Fahmi Zaïri та Iurii Vozniak. "A Coupled Electro-Mechanical Homogenization-Based Model for PVDF-Based Piezo-Composites Considering α → β Phase Transition and Interfacial Damage". Polymers 15, № 14 (10 липня 2023): 2994. http://dx.doi.org/10.3390/polym15142994.

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Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a piezoelectric semi-crystalline polymer whose electro-mechanical properties may be modulated via strain-induced α → β phase transition and the incorporation of polarized inorganic particles. The present work focuses on the constitutive representation of PVDF-based piezo-composites developed within the continuum-based micromechanical framework and considering the combined effects of particle reinforcement, α → β phase transition, and debonding along the interface between the PVDF matrix and the particles under increasing deformation. The micromechanics-based model is applied to available experimental data of PVDF filled with various concentrations of barium titanate (BaTiO3) particles. After its identification and predictability verification, the model is used to provide a better understanding of the separate and synergistic effects of BaTiO3 particle reinforcement and the micromechanical deformation processes on the electro-mechanical properties of PVDF-based piezo-composites.

21

Biscani, Fabio, Yao Koutsawa, Salim Belouettar, and Erasmo Carrera. "Effective Properties of Electro-Elastic Composites with Multi-Coating Inhomogeneities." Advanced Materials Research 93-94 (January 2010): 190–93. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.190.

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This work presents a micromechanics-based model to investigate the effective thermo-electric properties of piezoelectric composite materials. The effective thermo-electric properties are derived by considering a multi-coated ellipsoidal inhomogeneity embedded in a host material in the framework of the generalized self-consistent method (GSCM). An incremental scheme, in which the reinforcements are incrementally put in the host material, is implemented. The validation of the micromechanical model is performed with experimental data. The model proposed has a wide range of applications and can be extended to other physical properties.

22

Huber, J. E. "Micromechanical modeling of ferroelectric films." Journal of Materials Research 21, no. 3 (March 1, 2006): 557–62. http://dx.doi.org/10.1557/jmr.2006.0082.

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Ferroelectric films are growing in significance as non-volatile memory devices, sensors, and microactuators. The stress state of the film, induced by processing or constraints such as the substrate, strongly affects device behavior. Thus, it is important to be able to model the coupled and constrained behavior of film material. This work presents a preliminary study of the application of micromechanical modeling to ferroelectric films. A self-consistent micromechanics model developed for bulk ferroelectrics is adapted for thin film behavior by incorporating several features of the microstructure, mechanical clamping by the substrate, residual stresses, and the crystallographic orientation of the film.

23

Šmilauer, Vít, Lenka Dohnalová, Milan Jirásek, Julien Sanahuja, Suresh Seetharam, and Saeid Babaei. "Benchmarking Standard and Micromechanical Models for Creep and Shrinkage of Concrete Relevant for Nuclear Power Plants." Materials 16, no. 20 (October 18, 2023): 6751. http://dx.doi.org/10.3390/ma16206751.

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The creep and shrinkage of concrete play important roles for many nuclear power plant (NPP) and engineering structures. This paper benchmarks the standard and micromechanical models using a revamped and appended Northwestern University database of laboratory creep and shrinkage data with 4663 data sets. The benchmarking takes into account relevant concretes and conditions for NPPs using 781 plausible data sets and 1417 problematic data sets, which cover together 47% of the experimental data sets in the database. The B3, B4, and EC2 models were compared using the coefficient of variation of error (CoV) adjusted for the same significance for short-term and long-term measurements. The B4 model shows the lowest variations for autogenous shrinkage and basic and total creep, while the EC2 model performs slightly better for drying and total shrinkage. In addition, confidence levels at 5, 10, 90, and 95% are quantified in every decade. Two micromechanical models, Vi(CA)2T and SCK CEN, use continuum micromechanics for the mean field homogenization and thermodynamics of the water–pore structure interaction. Validations are carried out for the 28-day Young’s modulus of concrete, basic creep compliance, and drying shrinkage of paste and concrete. The Vi(CA)2T model is the second best model for the 28-day Young’s modulus and the basic creep problematic data sets. The SCK CEN micromechanical model provides good prediction for drying shrinkage.

24

Hou, Yueqin, Yun Chen, Haiwei Zou, Xiaoping Ji, Dongye Shao, Zhengming Zhang, and Ye Chen. "Investigation of Surface Micro-Mechanical Properties of Various Asphalt Binders Using AFM." Materials 15, no. 12 (June 20, 2022): 4358. http://dx.doi.org/10.3390/ma15124358.

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The microstructure of asphalt affects the micro-mechanical properties. In this study, atomic force microscopy (AFM) was used to investigate the surface elastic modulus and nanohardness of asphalt binder. Relevant mechanical indexes were quantitatively evaluated by contact mechanical model. Five types of asphalts, including different grades, oil sources, and before and after modification, were selected as test objects, and the effects of asphalt binder type, aging, water, and anti-stripping agent on the asphalt micromechanics were explored. The results showed that the micromechanical properties of asphalt binder are affected by grade, oil source, and modification. The aging resistance of modified asphalt binder is better than that of unmodified asphalt binder. Water immersion reduces the surface micromechanical properties of the asphalt binder. The effect of the anti-stripping agent on the modified asphalt binder is greater than that of the unmodified asphalt binder.

25

Siorikis, Dimitris K., Christos V. Nastos, Dimitris A. Saravanos, and Esteban Martino Gonzalez. "A Strain-rate Dependant Micromechanical Finite Element Model for High-velocity Impacts on Laminated Composite Plates." MATEC Web of Conferences 304 (2019): 01009. http://dx.doi.org/10.1051/matecconf/201930401009.

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A novel multi-scale numerical model for the simulation of high-velocity impacts on laminated composite plates is developed, which encompasses a micromechanics module for the accurate assessment of damage initiation and growth in the individual composite micromechanical constituents and for the efficient inclusion of strain rate effects into the analysis. A series of woven carbon/epoxy plate specimens impacted by steel ball impactors of high velocities and energies reaching and exceeding the ballistic limit (m=110 g, v=60-100 m/s, E=200-500 J) are also investigated. Ultimately, key impact simulation results, such as the ballistic limit and induced impact damage, are correlated with representative experimental results, demonstrating the validity of the proposed impact model.

26

Moheimani, Reza, and M. Hasansade. "A closed-form model for estimating the effective thermal conductivities of carbon nanotube–polymer nanocomposites." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 8 (August 31, 2018): 2909–19. http://dx.doi.org/10.1177/0954406218797967.

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This paper describes a closed-form unit cell micromechanical model for estimating the effective thermal conductivities of unidirectional carbon nanotube reinforced polymer nanocomposites. The model incorporates the typically observed misalignment and curvature of carbon nanotubes into the polymer nanocomposites. Also, the interfacial thermal resistance between the carbon nanotube and the polymer matrix is considered in the nanocomposite simulation. The micromechanics model is seen to produce reasonable agreement with available experimental data for the effective thermal conductivities of polymer nanocomposites reinforced with different carbon nanotube volume fractions. The results indicate that the thermal conductivities are strongly dependent on the waviness wherein, even a slight change in the carbon nanotube curvature can induce a prominent change in the polymer nanocomposite thermal conducting behavior. In general, the carbon nanotube curvature improves the nanocomposite thermal conductivity in the transverse direction. However, using the straight carbon nanotubes leads to maximum levels of axial thermal conductivities. With the increase in carbon nanotube diameter, an enhancement in nanocomposite transverse thermal conductivity is observed. Also, the results of micromechanical simulation show that it is necessary to form a perfectly bonded interface if the full potential of carbon nanotube reinforcement is to be realized.

27

Jones, Christopher A. R., Matthew Cibula, Jingchen Feng, Emma A. Krnacik, David H. McIntyre, Herbert Levine, and Bo Sun. "Micromechanics of cellularized biopolymer networks." Proceedings of the National Academy of Sciences 112, no. 37 (August 31, 2015): E5117—E5122. http://dx.doi.org/10.1073/pnas.1509663112.

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Collagen gels are widely used in experiments on cell mechanics because they mimic the extracellular matrix in physiological conditions. Collagen gels are often characterized by their bulk rheology; however, variations in the collagen fiber microstructure and cell adhesion forces cause the mechanical properties to be inhomogeneous at the cellular scale. We study the mechanics of type I collagen on the scale of tens to hundreds of microns by using holographic optical tweezers to apply pN forces to microparticles embedded in the collagen fiber network. We find that in response to optical forces, particle displacements are inhomogeneous, anisotropic, and asymmetric. Gels prepared at 21 °C and 37 °C show qualitative difference in their micromechanical characteristics. We also demonstrate that contracting cells remodel the micromechanics of their surrounding extracellular matrix in a strain- and distance-dependent manner. To further understand the micromechanics of cellularized extracellular matrix, we have constructed a computational model which reproduces the main experiment findings.

28

Yan, Shirong, Binglei Wang, Yu Sun, and Boning Lyu. "Micromechanics-Based Prediction Models and Experimental Validation on Elastic Modulus of Recycled Aggregate Concrete." Sustainability 13, no. 20 (October 10, 2021): 11172. http://dx.doi.org/10.3390/su132011172.

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Elastic modulus is one of the most important mechanical properties of concrete (including recycled aggregate concrete), and it has a notable guiding significance for engineering. There is a lack of micromechanical research on the elastic modulus of recycled aggregate concrete. This paper adopts four models based on micromechanics, including the Voigt model, Reuss model, Eshelby method, and Mori–Tanaka method, to predict the elastic modulus of recycled aggregate concrete. The optimal model is determined by comparing the results of the four models with the experimental data. On this basis, some previous prediction methods for the elastic modulus of concrete are employed to be compared with the most satisfactory models in this paper. Several experimental data from the open literature are also utilized to better illustrate the reliability of the prediction models. It is concluded that the Mori–Tanaka method unfailingly produces more accurate predictions compared to other models. It gives the best overall approximation for various data and has extensive effects in predicting the elastic modulus of RAC. This work may be helpful in promoting the development of micromechanics research in recycled aggregate concrete.

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Djaja, R. G., P. J. Moss, A. J. Carr, G. A. Carnaby, and D. H. Lee. "Finite Element Modeling of an Oriented Assembly of Continuous Fibers." Textile Research Journal 62, no. 8 (August 1992): 445–57. http://dx.doi.org/10.1177/004051759206200803.

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A micromechanical model of the large displacement behavior of a sliver of oriented helical fibers has produced algorithms for predicting and updating all five independent mechanical constants. The incorporation of the micromechanics in a finite-element model of a uniform rope of initially untwisted fibrous material is described. The response of the whole model to combined external and torsional stresses such as occur during twist insertion is then described. A detailed analysis of the stresses and strains in the deformed model shows that fiber packing in the yarn is predicted to quickly become non-uniform. The inner regions become most densely packed, and fibers there are subject to the highest stress levels. Fibers further from the center largely avoid being stressed by moving toward the yarn axis.

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Lei, Yong-Peng, Hui Wang, and Qing-Hua Qin. "Micromechanical properties of unidirectional composites filled with single and clustered shaped fibers." Science and Engineering of Composite Materials 25, no. 1 (January 26, 2018): 143–52. http://dx.doi.org/10.1515/secm-2016-0088.

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AbstractComputational micromechanics provides an efficient strategy to optimize composite materials by addressing the effect of different material and geometric parameters involved. In the present paper, the effective transverse elastic properties for periodic composite materials reinforced with single and clustered polygonal fibers are evaluated using the micromechanical finite element formulation subject to periodic displacement boundary conditions. The cross-sectional shapes of polygonal fibers are assumed to be triangular, square, pentagonal, hexagonal, octagonal, and circular to perform comprehensive investigation. By applying a periodic displacement constraint along the boundary of the representative unit cell of the composite to meet the requirement of straight-line constraint during the deformation of the unit cell, the computational micromechanical modeling based on homogenization technology is established for evaluating the effects of fiber shape and cluster on the overall properties. Subsequently, the micromechanical model is divided into four submodels, which are solved by means of the finite element analysis for determining the traction distributions along the cell boundary. Finally, the effective orthotropic elastic constants of composites are obtained using the solutions of the linear system of equations involving traction integrations to investigate the effects of fiber shape and cluster on the overall properties.

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Yudhanto, A., Tong Earn Tay, and Vincent B. C. Tan. "Micromechanical Characterization Parameters for a New Failure Criterion for Composite Structures." Key Engineering Materials 306-308 (March 2006): 781–86. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.781.

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Strain Invariant Failure Theory (SIFT) is a newly-developed failure criterion for composite structures [8, 9]. SIFT comprises two main features, namely micromechanical finite element modification and critical strain invariant parameters. Micromechanical finite element modification is performed to incorporate residual strains between fibers and matrix into homogenized finite element lamina solution. The presence of residual strains takes into account the mechanical and thermal (environmental) effects. Critical strain invariant parameters can be obtained from simple tensile test by carefully observing the occurrence of damage initiation in composite constituent. Strain tensors extracted from experiment are substituted into strain invariant parameters of i J1 (first invariant of strain; i = f, m—fiber, matrix) and i vm ε (equivalent strain or von Mises strain; subscript vm stands for von Mises). As noted in [8, 9], three critical strain invariants were found to be the onset of composite failure for carbon-fiber/epoxy system; they are m J1−cr , f vm−cr ε and m vm−cr ε . Micromechanical characterization parameters aim to provide general insight on the critical state of strains in which damage initiation locus may be determined by using SIFT critical parameters. Micromechanical model was subjected to six different loading conditions (three normal deformations and three shear deformations) and strain tensors (ε1, ε2, ε3, ε12, ε13, ε23) were extracted from finite element analysis. Micromechanical characterization parameters were obtained by normalizing the strain invariants of micromechanics analysis with respect to critical strain invariant. Important issues such as effect of fiber volume fraction and fiber packing arrangement are briefly discussed.

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Karki, Pravat, Yong-Rak Kim, and Dallas N. Little. "Dynamic Modulus Prediction of Asphalt Concrete Mixtures through Computational Micromechanics." Transportation Research Record: Journal of the Transportation Research Board 2507, no. 1 (January 2015): 1–9. http://dx.doi.org/10.3141/2507-01.

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This paper presents a computational micromechanics modeling approach to predict the dynamic modulus of asphalt concrete mixtures. The modeling uses a finite element method combined with the micromechanical representative volume element (RVE) of mixtures and laboratory tests that characterize the properties of individual mixture constituents. The model treats asphalt concrete mixtures as heterogeneous with two primary phases: a linear viscoelastic fine aggregate matrix (FAM) phase and a linear elastic aggregate phase. The mechanical properties of each phase were experimentally obtained by conducting constitutive tests: oscillatory torsion tests for the viscoelastic FAM phase and quasistatic nanoindentation tests for the elastic aggregate particles. Material properties of each mixture phase were then used in the finite element simulation of two-dimensional mixture microstructures obtained from digital image processes of asphalt concrete mixtures. Model simulations were compared with the experimental dynamic moduli of asphalt concrete mixtures. Simulation results indicated that the micromechanical approach based on the mixture microstructure and phase properties could fairly predict the overall mixture properties that are typically obtained from laboratory mixture tests. Furthermore, the RVE dimension of 60 mm might be used to predict the undamaged viscoelastic stiffness characteristics of asphalt concrete mixtures with reduced computing efforts.

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Mirdehghan, Abolfazl, Hooshang Nosraty, Mahmood M. Shokrieh, Roohallah Ghasemi, and Mehdi Akhbari. "Micromechanical modelling of the compression strength of three-dimensional integrated woven sandwich composites." Journal of Industrial Textiles 48, no. 9 (March 16, 2018): 1399–419. http://dx.doi.org/10.1177/1528083718764909.

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This paper is concerned with a theoretical and experimental verification of a micromechanical model of newly developed sandwich panels denoted as 3D integrated woven sandwich composite panels. The integrated hollow core was made of a pile of 3D bars with a special configuration. Integrated woven sandwich composite panels consist of two fabric faces which were interwoven by pile fibers and therefore a very high skin core debonding resistance was obtained. With the objective of qualifying the mechanical properties of these structures, fairly extensive experimental research was carried out by investigators. Although some numerical methods have been developed to predict the mechanical behaviors of these structures, there are less analytical models in this area. Due to the computational difficulties and the time consuming nature of the finite element method, in the present study, a new micromechanics analytical model has been suggested for predicting the compressive strength of integrated woven sandwich composites. In order to evaluate the proposed model, fabricated samples with different pile heights and pile distribution densities were subjected to flatwise compression tests. The results show that compressive properties of integrated woven sandwich composite panels are decreased with the increase of core heights and increased greatly with that of the pile density. Furthermore, the micromechanics model reasonably predicted the compression strength, and there is a good agreement between the experimental data and model predictions.

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Pinho, S. T., R. Gutkin, S. Pimenta, N. V. De Carvalho, and P. Robinson. "On longitudinal compressive failure of carbon-fibre-reinforced polymer: from unidirectional to woven, and from virgin to recycled." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1965 (April 28, 2012): 1871–95. http://dx.doi.org/10.1098/rsta.2011.0429.

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Modelling the longitudinal compressive failure of carbon-fibre-reinforced composites has been attempted for decades. Despite many developments, no single model has surfaced to provide simultaneously a definitive explanation for the micromechanics of failure as well as validated predictions for a generic stress state. This paper explores the reasons for this, by presenting experimental data (including scanning electron microscopic observations of loaded kink bands during propagation, and brittle shear fracture at 45 ° to the fibres) and reviewing previously proposed micromechanical analytical and numerical models. The paper focuses mainly on virgin unidirectional (UD) composites, but studies for woven and recycled composites are also presented, highlighting similarities and differences between these cases. It is found that, while kink-band formation (also referred to in the literature as microbuckling) is predominant in UD composites under longitudinal compression, another failure mode related to the failure of the fibres can be observed experimentally. It is also shown that the micromechanics of the failure process observed in UD composites is similar to that in other fibre architectures, hence encouraging the adaptation and application of models developed for the former to the latter.

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Lu, Zucheng, Heying Hou, Pengming Jiang, Qing Wang, Tianxiang Li, and Zhuojie Pan. "Three-Dimensional Discrete Element Analysis of Crushing Characteristics of Calcareous Sand Particles." Geofluids 2022 (March 18, 2022): 1–9. http://dx.doi.org/10.1155/2022/8957574.

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Particle crushing is an important factor affecting the mechanical characteristics of calcareous sand, but at present, most of relative studying methods rely on physical experiments. In order to study the influence of particle crushing characteristics on the micromechanics of calcareous sand, the 14-fragment replacement method satisfying the Apollonian distribution is used to simulate the calcareous sand particles, and the fragment replacement method (FRM) is used to simulate the particle crushing. The three-dimensional discrete element model of calcareous sand particle crushing is established, and the development of relative crushing rate and the evolution laws of coordination number, porosity, and sliding contact ratio in triaxial consolidated drained shear test are analyzed. The results show that the three-dimensional model considering particle breakage can well reflect the micromechanical properties of the internal structure of the sample. The micromechanical response with and without particle crushing is quite different, which can be well reflected by the numerical test under high confining pressure. In addition, the modified relative crushing rate proposed by Einav based on the research of Hardin can better describe the relative crushing rate of calcareous sand under wide gradation and can provide a reference for the study of particle crushing characteristics of laboratory test of calcareous sand under wide gradation.

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Amraei, Jafar, Jafar E. Jam, Behrouz Arab, and Roohollah D. Firouz-Abadi. "Effect of interphase zone on the overall elastic properties of nanoparticle-reinforced polymer nanocomposites." Journal of Composite Materials 53, no. 9 (September 12, 2018): 1261–74. http://dx.doi.org/10.1177/0021998318798443.

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In the current work, the effect of interphase region on the mechanical properties of polymer nanocomposites reinforced with nanoparticles is studied. For this purpose, a closed-form interphase model as a function of radial distance based on finite-size representative volume element is suggested to estimate the mechanical properties of particle-reinforced nanocomposites. The effective Young’s and shear moduli of thermoplastic polycarbonate-based nanocomposites for a wide range of sizes and volume fractions of silicon carbide nanoparticles are investigated using the proposed interphase model and molecular dynamics simulations. In order to investigate the effect of particle size, several unit cells of the same volume fraction, but with different particle radii have been considered. The micromechanics-based homogenization results are in good agreement with the results of molecular dynamics simulations for all models. This study demonstrates that the suggested micromechanical interphase model has the capacity to estimate effective mechanical properties of polymer-based nanocomposites reinforced with spherical inclusions.

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Shen, Y.-L. "Void nucleation in metal interconnects: Combined effects of interface flaws and crystallographic slip." Journal of Materials Research 14, no. 2 (February 1999): 584–91. http://dx.doi.org/10.1557/jmr.1999.0083.

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A micromechanical model of void nucleation in passivated metal interconnection lines is proposed. The model is based on the evolution of stress and strain fields in a two-dimensional model system, obtained from numerical modeling. Interface flaws in the form of debond between the metal and the surrounding dielectric are assumed to exist. A unique pattern of shear stress resolved on the slip systems in the metal line, due to the presence of pre-existing debond, is found. A dislocation slip model is constructed in accordance with the shear mode. The mechanism of crystallographic slip is such that lateral thinning of the metal line at the debond region together with the slip step produced at the edges of debond lead to a net transport of atoms away from the debond area, and a physical void is thus formed. The significance and implications of this proposed micromechanism are discussed.

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Jia, Chenxue, Taihua Zhang, and Haifeng Zhao. "A computational micromechanics model to predict mechanical properties of porous silica aerogels." Journal of Applied Physics 132, no. 15 (October 21, 2022): 155102. http://dx.doi.org/10.1063/5.0109223.

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Porous silica aerogel is an ultra-low-density material with nanostructures that leads to its excellent physio-chemical properties. Considering the characteristics of the material, a micromechanical model to assess the microstructure–property relations is highly demanded. In this study, a cuboctahedron unit cell is proposed as a representative volume element of the silica aerogel to correlate with its density and compressive stress–strain curves. The backbone lattice-structure combined with the dead ends is established to represent the periodic configuration of the aerogel. It is implemented in both the numerical scheme with the finite element method and the analytical model by modifying the Gibson–Ashby model. Furthermore, the crushing behaviors of the material under large deformation are discussed in the numerical study. Due to the features of load-bearing skeletons and non-load-bearing short pillars, the compression process of the silica aerogel exhibits strong nonlinear behaviors. Overall, this computational micromechanics model is capable of accurately simulating the stress–strain curves of silica aerogels with different densities under different loading levels. This work provides a general framework to quantify the microstructure–property relations of porous silica aerogels and also other porous materials.

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Zhou, Shuai, Yue Jia, and Chong Wang. "Global Sensitivity Analysis for the Polymeric Microcapsules in Self-Healing Cementitious Composites." Polymers 12, no. 12 (December 15, 2020): 2990. http://dx.doi.org/10.3390/polym12122990.

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Cementitious composites with microencapsulated healing agents are appealing due to the advantages of self-healing. The polymeric shell and polymeric healing agents in microcapsules have been proven effective in self-healing, while these microcapsules decrease the effective elastic properties of cementitious composites before self-healing happens. The reduction of effective elastic properties can be evaluated by micromechanics. The substantial complicacy included in micromechanical models leads to the need of specifying a large number of parameters and inputs. Meanwhile, there are nonlinearities in input–output relationships. Hence, it is a prerequisite to know the sensitivity of the models. A micromechanical model which can evaluate the effective properties of the microcapsule-contained cementitious material is proposed. Subsequently, a quantitative global sensitivity analysis technique, the Extended Fourier Amplitude Sensitivity Test (EFAST), is applied to identify which parameters are required for knowledge improvement to achieve the desired level of confidence in the results. Sensitivity indices for first-order effects are computed. Results show the volume fraction of microcapsules is the most important factor which influences the effective properties of self-healing cementitious composites before self-healing. The influence of interfacial properties cannot be neglected. The research sheds new light on the influence of parameters on microcapsule-contained self-healing composites.

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Brighenti, Roberto, Federico Artoni, and Mattia Pancrazio Cosma. "Viscous and Failure Mechanisms in Polymer Networks: A Theoretical Micromechanical Approach." Materials 12, no. 10 (May 14, 2019): 1576. http://dx.doi.org/10.3390/ma12101576.

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Polymeric materials typically present a complex response to mechanical actions; in fact, their behavior is often characterized by viscous time-dependent phenomena due to the network rearrangement and damage induced by chains’ bond scission, chains sliding, chains uncoiling, etc. A simple yet reliable model—possibly formulated on the basis of few physically-based parameters—accounting for the main micro-scale micromechanisms taking place in such a class of materials is required to properly describe their response. In the present paper, we propose a theoretical micromechanical approach rooted in the network’s chains statistics which allows us to account for the time-dependent response and for the chains failure of polymer networks through a micromechanics formulation. The model is up-scaled to the mesoscale level by integrating the main field quantities over the so-called ‘chains configuration space’. After presenting the relevant theory, its reliability is verified through the analysis of some representative tests, and some final considerations are drawn.

41

Wei, Wei, Chongshi Gu, Xuyuan Guo, and Shuitao Gu. "Micromechanical modelling of the anisotropic creep behaviour of granular medium as a fourth-order fabric tensor." Advances in Mechanical Engineering 13, no. 7 (July 2021): 168781402110361. http://dx.doi.org/10.1177/16878140211036127.

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The main objective of the present work is to develop a micromechanics approach to predict the macroscopic anisotropic creep behaviour of granular media. To this end, the linear viscoelastic behaviour of the inter-particle interaction at contact is adopted, and the contact distribution is characterized by a fourth-order fabric tensor in the local scale. Then, fourth-order tensor fabric-based micromechanical approaches based on Voigt and Reuss localization assumptions are applied to granular media in the Laplace–Carson space. With help of the inverse Laplace–Carson transformation of these obtained models, the macroscopic anisotropic creep behaviour of granular media submitted to a constant external loading is examined. Finally, the obtained results by specializing the Burgers model into the obtained models are compared with the numerical simulations in the particle flow code (PFC2D) to illustrate the validation and the accuracy of the analytical models for the macroscopic anisotropic creep behaviour of granular media.

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Rosca, Victoria Elena, Nicolae Ţăranu, Liliana Bejan, and Andrei Octav Axinte. "Element Free Galerkin Formulation for Problems in Composite Micromechanics." Applied Mechanics and Materials 809-810 (November 2015): 896–901. http://dx.doi.org/10.4028/www.scientific.net/amm.809-810.896.

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The heterogeneity and anisotropy of structural composites make the application of the standard mesh-based methods using the meshing of interfacial region between matrix and fibers a difficult task. The objective of this study is to present the EFG formulation for problems of composite micromechanics. It is expected that the tediousness and approximations involved in mesh generation, and hence inaccuracies in the results can be avoided using the new meshless techniques such as the Element Free Galerkin (EFG) method. The theoretical methodologies, computer implementations and practical application are carried out. Periodic boundary conditions of the unit cell under tensile load are set up. The method of Lagrange multipliers is introduced for the treatment of material discontinuity at the fiber-matrix interface in which both the displacement continuity and traction reciprocity are satisfied. The EFG method is formulated for the generalized plane strain problems. Examples are presented to illustrate the effectiveness of the proposed micromechanical model, and it is validated by comparing the results with available numerical solutions.

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Timothy, Jithender J., Alexander Haynack, Thomas Kränkel, and Christoph Gehlen. "What Is the Internal Pressure That Initiates Damage in Cementitious Materials during Freezing and Thawing? A Micromechanical Analysis." Applied Mechanics 3, no. 4 (November 5, 2022): 1288–98. http://dx.doi.org/10.3390/applmech3040074.

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Damage induced by repetitive freezing and thawing processes is one of the critical factors that affect concrete durability in cold climates. This deterioration process manifests as surface scaling and internal damage. The damage processes are governed by physicochemical mechanisms that are active across multiple scales. In this contribution, we present a novel multiscale theoretical framework for estimating the critical pressure required for microcrack initiation during freezing and thawing of cementitious mortar. Continuum micromechanics and fracture mechanics is used to model the phenomena of microcrack initiation and growth. Damage at the microscale is upscaled to the level of the specimen using multilevel homogenization. The critical pressure is estimated using poromechanics at the microscopic scale. A theoretical analysis shows that in the frozen state, the material can resist higher pressures. As a consequence, the material is more susceptible to damage during thawing. The micromechanical predictions are within the range of the predictions obtained by electrokinetic theory.

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Zhang, Yingmin, Guang Yang, Dongxu Liu, Wenwu Chen, and Lizhi Sun. "Micromechanics and Ultrasonic Propagation in Consolidated Earthen-Site Soils." Materials 16, no. 22 (November 10, 2023): 7117. http://dx.doi.org/10.3390/ma16227117.

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Although nondestructive ultrasonic technologies have been applied in laboratory and field tests in the field of heritage conservation, few studies have quantified the relationship among the real microstructures, micromechanical properties, and macroscopic acoustic responses of earthen-site soils. This paper develops a micromechanics-based multiscale model for quantitatively exploring the ultrasonic propagation characteristics of elastic waves in untreated and consolidated earthen-site soils. Scanning electron microscope images and image processing technology are integrated into the finite-element simulation. The effects of microstructure and wave features on the acoustic characteristics of soils are quantitatively investigated under pulsive loading. The simulation results of untreated and consolidated soils are efficiently compared to ultrasonic test data. It is demonstrated that the integration of microstructure image processing and multiscale modeling can predict the ultrasonic pulse velocity well, which improves the accuracy of laboratory testing and field monitoring and better serves the evaluation and implementation of engineering practice in the field of heritage conservation.

45

Kontou, E. "Micromechanics model for particulate composites." Mechanics of Materials 39, no. 7 (July 2007): 702–9. http://dx.doi.org/10.1016/j.mechmat.2006.12.001.

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46

Fukazawa, Tatsuya. "A model of cochlear micromechanics." Hearing Research 113, no. 1-2 (November 1997): 182–90. http://dx.doi.org/10.1016/s0378-5955(97)00138-x.

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47

Mahmoodi, M. J., M. M. Aghdam, and M. Shakeri. "The effects of interfacial debonding on the elastoplastic response of unidirectional silicon carbide—titanium composites." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 2 (February 1, 2010): 259–69. http://dx.doi.org/10.1243/09544062jmes1681.

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A three-dimensional micromechanics-based analytical model is presented to investigate the effects of initiation and propagation of interface damage on the elastoplastic behaviour of unidirectional SiC—Ti metal matrix composites (MMCs) subjected to off-axis loading. Temperature-dependent properties are considered for the matrix. Manufacturing process thermal residual stress (RS) is also included in the model. The selected representative volume element consists of r× c unit cells in which a quarter of the fibre is surrounded by matrix sub-cells. The constant compliance interface model is used to model interfacial debonding and the successive approximation method together with von Mises yield criterion is used to obtain elastoplastic behaviour. Dominance mode of damage including fibre fracture, interfacial debonding, and matrix yielding and ultimate tensile strength of the SiC—Ti MMC are predicted for various loading directions. The effects of thermal RS and fibre volume fraction on the stress—strain response of the SiC—Ti MMC are studied. Results revealed that for more realistic predictions, both interface damage and thermal RS effects should be considered in the analysis. The contribution of interfacial debonding and thermal RS in the overall behaviour of the material is also investigated. Comparison between results of the presented model shows very good agreement with the finite-element micromechanical analysis and experiment for various off-axis angles.

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Su, Y., and G. J. Weng. "A polycrystal hysteresis model for ferroelectric ceramics." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 462, no. 2069 (February 14, 2006): 1573–92. http://dx.doi.org/10.1098/rspa.2005.1616.

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Most key elements of ferroelectric properties are defined through the hysteresis loops. For a ferroelectric ceramic, its loop is contributed collectively by its constituent grains, each having its own hysteresis loop when the ceramic polycrystal is under a cyclic electric field. In this paper, we propose a polycrystal hysteresis model so that the hysteresis loop of a ceramic can be calculated from the loops of its constituent grains. In this model a micromechanics-based thermodynamic approach is developed to determine the hysteresis behaviour of the constituent grains, and a self-consistent scheme is introduced to translate these behaviours to the polycrystal level. This theory differs from the classical phenomenological ones in that it is a micromechanics-based thermodynamic approach and it can provide the evolution of new domain concentration among the constituent grains. It also differs from some recent micromechanics studies in its secant form of self-consistent formulation and in its application of irreversible thermodynamics to derive the kinetic equation of domain growth. To put this two-level micromechanics theory in perspective, it is applied to a ceramic PLZT 8/65/35, to calculate its hysteresis loop between the electric displacement and the electric field ( D versus E ), and the butterfly-shaped longitudinal strain versus the electric field relation ( ϵ versus E ). The calculated results are found to be in good quantitative agreement with the test data. The corresponding evolution of new domain concentration c 1 and the individual hysteresis loops of several selected grains—along with those of the overall polycrystal—are also illustrated.

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Ostoja-Starzewski, Martin. "Lattice models in micromechanics." Applied Mechanics Reviews 55, no. 1 (January 1, 2002): 35–60. http://dx.doi.org/10.1115/1.1432990.

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This review presents the potential that lattice (or spring network) models hold for micromechanics applications. The models have their origin in the atomistic representations of matter on one hand, and in the truss-type systems in engineering on the other. The paper evolves by first giving a rather detailed presentation of one-dimensional and planar lattice models for classical continua. This is followed by a section on applications in mechanics of composites and key computational aspects. We then return to planar lattice models made of beams, which are a discrete counterpart of non-classical continua. The final two sections of the paper are devoted to issues of connectivity and rigidity of networks, and lattices of disordered (rather than periodic) topology. Spring network models offer an attractive alternative to finite element analyses of planar systems ranging from metals, composites, ceramics and polymers to functionally graded and granular materials, whereby a fiber network model of paper is treated in considerable detail. This review article contains 81 references.

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HUANG, ZHUPING, YONGQIANG CHEN, and SHU-LIN BAI. "AN ELASTOPLASTIC CONSTITUTIVE MODEL FOR POROUS MATERIALS." International Journal of Applied Mechanics 05, no. 03 (September 2013): 1350035. http://dx.doi.org/10.1142/s175882511350035x.

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A micromechanics-based elastoplastic constitutive model for porous materials is proposed. With an assumption of modified three-dimensional Ramberg–Osgood equation for the compressible matrix material, the variational principle based on a linear comparison composite is applied to study the effective mechanical properties of the porous materials. Analytical expressions of elastoplastic constitutive relations are derived by means of micromechanics principles and homogenization procedures. It is demonstrated that the derived expressions do not involve any additional material constants to be fitted with experimental data. The model can be useful in the prediction of mechanical properties of elastoplastic porous solids.

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