Mechanical Responses of Primary-α Ti Grains in Polycrystalline Samples: Part II—Bayesian Estimation of Crystal-Level Elastic-Plastic Mechanical Properties from Spherical Indentation Measurements

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

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Symmetric Nature of Stress Distribution in the Elastic-Plastic Range of Pinus L. Pine Wood Samples Determined Experimentally and Using the Finite Element Method (FEM)

Symmetry ◽

10.3390/sym13010039 ◽

2020 ◽

Vol 13 (1) ◽

pp. 39

Author(s):

Łukasz Warguła ◽

Dominik Wojtkowiak ◽

Mateusz Kukla ◽

Krzysztof Talaśka

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Stress Distribution ◽

Moisture Content ◽

Tool Geometry ◽

Wood Fibers ◽

Data Set ◽

Plastic Deformations ◽

Pine Wood ◽

Elastic Plastic

This article presents the results of experimental research on the mechanical properties of pine wood (Pinus L. Sp. Pl. 1000. 1753). In the course of the research process, stress-strain curves were determined for cases of tensile, compression and shear of standardized shapes samples. The collected data set was used to determine several material constants such as: modulus of elasticity, shear modulus or yield point. The aim of the research was to determine the material properties necessary to develop the model used in the finite element analysis (FEM), which demonstrates the symmetrical nature of the stress distribution in the sample. This model will be used to analyze the process of grinding wood base materials in terms of the peak cutting force estimation and the tool geometry influence determination. The main purpose of the developed model will be to determine the maximum stress value necessary to estimate the destructive force for the tested wood sample. The tests were carried out for timber of around 8.74% and 19.9% moisture content (MC). Significant differences were found between the mechanical properties of wood depending on moisture content and the direction of the applied force depending on the arrangement of wood fibers. Unlike other studies in the literature, this one relates to all three stress states (tensile, compression and shear) in all significant directions (anatomical). To verify the usability of the determined mechanical parameters of wood, all three strength tests (tensile, compression and shear) were mapped in the FEM analysis. The accuracy of the model in determining the maximum destructive force of the material is equal to the average 8% (for tensile testing 14%, compression 2.5%, shear 6.5%), while the average coverage of the FEM characteristic with the results of the strength test in the field of elastic-plastic deformations with the adopted ±15% error overlap on average by about 77%. The analyses were performed in the ABAQUS/Standard 2020 program in the field of elastic-plastic deformations. Research with the use of numerical models after extension with a damage model will enable the design of energy-saving and durable grinding machines.

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Effect of Defect on Elastic/Plastic and Creep Behavior of Bone: A Finite Element Study

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-175843 ◽

2007 ◽

Author(s):

A. Ajdari ◽

P. K. Canavan ◽

H. Nayeb-Hashemi ◽

G. Warner

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Trabecular Bone ◽

Fatigue Loading ◽

Dimensional Structure ◽

Plastic Behavior ◽

Element Analysis ◽

Elastic Plastic ◽

Local Bone ◽

Osteoporotic Vertebral Fractures

Three-dimensional structure of trabecular bone can be modeled by 2D or 3D Voronoi structure. The effect of missing cell walls on the mechanical properties of 2D honeycombs is a first step towards understanding the effect of local bone resorption due to osteoporosis. In patients with osteoporosis, bone mass is lost first by thinning and then by resorption of the trabeculae [1]. Furthermore, creep response is important to analyze in cellular solids when the temperature is high relative to the melting temperature. For trabecular bone, as body temperature (38 °C) is close to the denaturation temperature of collagen (52 °C), trabecular bone creeps [1]. Over the half of the osteoporotic vertebral fractures that occur in the elderly, are the result of the creep and fatigue loading associated with the activities of daily living [2]. The objective of this work is to understand the effect of missing walls and filled cells on elastic-plastic behavior of both regular hexagonal and non-periodic Voronoi structures using finite element analysis. The results show that the missing walls have a significant effect on overall elastic properties of the cellular structure. For both regular hexagonal and Voronoi materials, the yield strength of the structure decreased by more than 60% by introducing 10% missing walls. In contrast, the results indicate that filled cells have much less effect on the mechanical properties of both regular hexagonal and Voronoi materials.

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Electrical and Mechanical Properties of the Red and White Muscles in the Silver Carp

Journal of Experimental Biology ◽

10.1242/jeb.57.2.551 ◽

1972 ◽

Vol 57 (2) ◽

pp. 551-567

Author(s):

T. YAMAMOTO

Keyword(s):

Mechanical Properties ◽

White Muscle ◽

Silver Carp ◽

Membrane Resistance ◽

Resting Potential ◽

Resting Membrane Potential ◽

Mechanical Responses ◽

Red Muscle ◽

Red And White Muscles ◽

Specific Membrane

1. Electrical and mechanical properties of the red muscle (M. levator pinnae pectoralis) and white muscle (M. levator pinnae lateralis abdominis) in the silver carp (Carassius auratus Linné) were investigated by using caffeine and thymol. 2. A complete tetanus could be produced in the red muscle. But in the white muscle no tetanus was produced and there was a gradual decrease in tension during continuous stimulation, even at a frequency of 1 c/s or less. 3. Caffeine (0.5-1 mM) and thymol (0.25-0.5 mM) potentiated the twitch tension in both muscles without an increase in the resting tension; they produced a contracture in both muscles when the concentration was increased further. 4. The falling phase of the active state of contraction was nearly the same in both muscles and was prolonged by caffeine (0.5 mmM) and by thymol (0.25 mM). 5. The resting membrane potential of the red muscle was scarcely affected by caffeine (0.5-5 mM), whereas in the white muscles a depolarization of 10 mV was observed with caffeine of more than 2 mM. The resting potential of both muscles was little changed by o.25 mm thymol. However, at a concentration of more than 0.5mM thymol depolarized the membrane in both muscles to the same extent. 6. In caffeine (2-3 mM) solution the mean specific membrane resistance was reduced from 8.8 kΩ cm2 to 6.0 kΩ cm2 in the red muscle, and from 5.0 kΩ cm2 to 2.7 kΩ cm2 in the white muscle. In thymol (0.5-1 mM) solution it was reduced from 11.2 kΩcm2 to 6.5 kΩ cm2 in the red muscle, and from 5.4kΩ cm2 to 3.1 kΩ) cm2 in the white muscle. The specific membrane capacitance, calculated from the time constant and the membrane resistance, remained more or less the same in both muscles after a treatment with these agents. 7. Electrical properties of the muscles and the effects of caffeine and thymol on mechanical responses suggest that there are no fundamental differences between red and white muscles except for the excitation-contraction coupling. A lack of summation of twitch, a successive decline of twitch, and inability to produce potassium contracture in the white muscle may be due to the fact that the Ca-releasing mechanism is easily inactivated by depolarization of the membrane.

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Mechanical Properties and Elastic-Plastic Constitutive Model for Autoclaved Aerated Concrete Block

ACI Materials Journal ◽

10.14359/51730415 ◽

2021 ◽

Vol 118 (2) ◽

Keyword(s):

Mechanical Properties ◽

Constitutive Model ◽

Concrete Block ◽

Elastic Plastic ◽

Autoclaved Aerated Concrete ◽

Aerated Concrete

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An automated confocal micro-extensometer enables in vivo quantification of mechanical properties with cellular resolution

10.1101/183533 ◽

2017 ◽

Author(s):

Sarah Robinson ◽

Michal Huflejt ◽

Pierre Barbier de Reuille ◽

Siobhan A. Braybrook ◽

Martine Schorderet ◽

...

Keyword(s):

Mechanical Properties ◽

Spatial Variation ◽

Genetic Regulation ◽

Relative Increase ◽

Spatial Gradient ◽

Creep Tests ◽

Mechanical Responses ◽

Cellular Resolution ◽

Improved Accuracy

AbstractHow complex developmental-genetic networks are translated into organs with specific 3D shapes remains an open question. This question is particularly challenging because the elaboration of specific shapes is in essence a question of mechanics. In plants, this means how the genetic circuitry affects the cell wall. The mechanical properties of the wall and their spatial variation are the key factors controlling morphogenesis in plants. However, these properties are difficult to measure and investigating their relation to genetic regulation is particularly challenging. To measure spatial variation of mechanical properties, one must determine the deformation of a tissue in response to a known force with cellular resolution. Here we present an automated confocal micro-extensometer (ACME), which greatly expands the scope of existing methods for measuring mechanical properties. Unlike classical extensometers, ACME is mounted on a confocal microscope and utilizes confocal images to compute the deformation of the tissue directly from biological markers, thus providing cellular scale information and improved accuracy. ACME is suitable for measuring the mechanical responses in live tissue. As a proof of concept we demonstrate that the plant hormone gibberellic acid induces a spatial gradient in mechanical properties along the length of the Arabidopsis hypocotyl.TermsStressis the force acting on the material per unit area.Strainthe relative increase in length of the material, and can be expressed as a percentage change in length.Mechanical propertiesdescribe the stress-strain relationship for a material. If we apply the same force to a material that is twice as thick/stiff? it will deform half as much, if the material is otherwise the same.Elasticelastic materials deform instantly and reversibly.Creepa time-dependent irreversible strain that occurs when a constant force is applied and maintained. Creep is measured using creep tests. A force is applied and maintained for a period of time. The force is removed to reveal the reversible and irreversible deformation.

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Effect of Crystallographic Orientation on Nanoindentation Response of Fe3Si Single-Crystals

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.784.44 ◽

2018 ◽

Vol 784 ◽

pp. 44-48 ◽

Cited By ~ 1

Author(s):

Jaroslav Čech ◽

Petr Haušild ◽

Aleš Materna

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Shear Stress ◽

Contact Area ◽

Measured Data ◽

Deformation Mechanisms ◽

Spherical Indentation ◽

Indentation Modulus ◽

Slip Systems ◽

Correct Interpretation

Deformation mechanisms and mechanical properties of Fe3(wt.%)Si single crystal in two different orientations were investigated by spherical indentation. For correct interpretation of measured data and better understanding of the deformation mechanisms under the contact area, finite element simulations were carried out and resolved shear stress in available slip systems was computed. Pop-in behavior, differences in hardness, indentation modulus and shapes of residual imprints were observed and associated with different activation of slip.

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