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

2018 ◽  
Vol 784 ◽  
pp. 44-48 ◽  
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.

Calculation of Cross Beam in Continuous Box Girder Bridge Based on Modified Shear Method

2014 ◽  
Vol 578-579 ◽  
pp. 642-647
Author(s):  
Ya Feng Gong ◽  
Xiao Bo Sun ◽  
Huan Li Wang ◽  
Hai Peng Bi
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Traditional Method ◽  
Element Model ◽  
Measured Data ◽  
Box Girder ◽  
Box Girder Bridge ◽  
Girder Bridge ◽  
Simplified Calculation ◽  
The Finite Element Model

The mechanical properties of cross beam in continuous box girder bridge can be obtained through analyzing the finite element model and measured data of bridge. A new simplified calculation method for cross beam is proposed in this paper, which is called modified shear method. Comparative analysis with traditional method is used to verify its feasibility and practicability.

scholarly journals Elastic-Perfectly Plastic Contact of Rough Surfaces: An Incremental Equivalent Circular Model

2021 ◽  
Author(s):  
GF WANG
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Yield Stress ◽  
Contact Area ◽  
Present Model ◽  
Rough Surfaces ◽  
Perfectly Plastic ◽  
Circular Model ◽  
Linear Load ◽  
Elastic Perfectly Plastic

In this paper, an incremental eqivalent contact model is developed for elastic-perfectly plastic solids with rough surfaces. The contact of rough surface is modeled by the accumulation of circular contacts with varying radius, which is estimated from the geometrical contact area and the number of contact patches. For three typical rough surfaces with various mechanical properties, the present model gives accurate predictions of the load-area relation, which are verified by direct finite element simulations. An approximately linear load-area relation is observed for elastic-plastic contact up to a large contact fraction of 15%, and the influence of yield stress is addressed.

Nonlinear Magnetostrictive Effect of Magnetorheological Elastomers

2013 ◽  
Vol 833 ◽  
pp. 291-294 ◽  
Author(s):  
Shu Lei Sun ◽  
Xiong Qi Peng ◽  
Zao Yang Guo
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Finite Element ◽  
Volume Fraction ◽  
Nonlinear Function ◽  
Measured Data ◽  
Magnetorheological Elastomers ◽  
Smart Composites ◽  
Element Simulation ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) are a class of smart composites whose mechanical properties can be obviously changed under different magnetic field. Only a few works study its magnetostrictive property, which describes the changes in dimensions of a material in its magnetization. Magnetostriction in the ferromagnetic particle is also called eigenstrain in MREs. It is modeled using the nonlinear function of the magnetization in this article. The eigenstrain due to the magnetostriction is incorporated in the structure of the MREs using a generalized Hookes Law. By means of initial strain, a finite element simulation is presented to describe the magnetostriction of MREs. The results show that the magnetostriction along the magnetic field depends on the magnetization and the volume fraction of particles. As an application, we will present numerical simulations for a magnetostriction and compare these results with measured data.

Effect of Nonlinear Kinematic Hardening Constants on Cyclic Spherical Indentation Test

2010 ◽  
Author(s):  
A. Nayebi
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Applied Load ◽  
Kinematic Hardening ◽  
Hysteresis Loops ◽  
Indentation Test ◽  
Material Behavior ◽  
Spherical Indentation ◽  
Displacement Curve ◽  
Residual Displacements

In the last decade, instrumented indentation test has been widely used to determine the mechanical properties of different materials and especially for metals. The mechanical properties such as Young modulus, yield stress, hardening exponent, and stress-strain curve were determined with the help of the load–displacement curve of the continuous indentation test. The method consists of pushing an indenter in a material sample and the applied load and the indenter displacement are measured. In this research the load on the indenter was considered as cyclic and varied from zero to Fmax. Because of the Bauschinger effect, the hysteresis loops were formed. With the help of these hysteresis loops, nonlinear kinematic hardening parameters of the Armstrong–Freiderick (A-F) model can be determined. Spherical indenter was used and the sample was considered isotropic. The material behavior was modeled by the A-F rule. The test was modeled by the finite element method. An axi-symmetric mesh was used. The A–F model constants, C and γ, were varied to obtain their effects on the hysteresis loops. Maximum applied load was considered constant for different finite element modeling and the maximum and residual displacements were calculated from the simulations results. The normalized maximum and the residual displacements were increased as a function of the cycles. It was shown that these parameters value and their rate are dependent on the material model constants. These dependences were shown for different examples which can help to characterize the A-F model constants by the cyclic spherical indentation tests.

Characterization of mechanical properties of metallic foams by instrumented indentation test

2018 ◽  
Vol 115 (4) ◽  
pp. 405
Author(s):  
Ali Nayebi ◽  
Azam Surmiri
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Constitutive Model ◽  
Indentation Test ◽  
Metallic Foam ◽  
Spherical Indentation ◽  
Metallic Foams ◽  
Aluminum Foams ◽  
Inelastic Behaviour ◽  
Indentation Response

In this study, the spherical indentation tests with a spherical rigid indenter of 5 mm radius were used. The inelastic behaviour of metallic foam was considered as an isotropic crushable foam constitutive model of Deshpande and Fleck which has been shown experimentally that their model can be applied to aluminum foams. The spherical indentation test was modeled by finite element method. A 2D axisymmetric model was developed. Practically, the size of the indenter tip should be reasonably large compared to the size of the cells/pores in the specimen and the indentation depth should also be reasonably large so that the indentation response does reflect the averaged material behaviours, which are described by the aforementioned constitutive model. The applied load on the indenter versus its displacement was obtained under different metallic foam mechanical properties. Numerical results from the finite element simulations are used to obtain the dependence of the indentation response on the metallic foam material parameters which characterizes the plastic deformation of metallic foams. Finally, the stress–curves and the elastic modulus of different foams are obtained by the indentation curve, which is obtained by FEM.

Towards an improvement of performance of TiAlN hard coatings using metal interlayers

2002 ◽  
Vol 750 ◽  
Author(s):  
J. M. Castanho ◽  
M. T. Vieira
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Shear Stress ◽  
High Speed ◽  
Cutting Tools ◽  
Hard Coatings ◽  
Deformation Mechanisms ◽  
Multilayer Coatings ◽  
High Speed Machining ◽  
High Speed Cutting

ABSTRACTTiAlN sputtered coatings have been used with success in high-speed cutting tools in the last few years. However, the adhesive failures of the coatings refrain its application in more severe wear conditions like as high-speed machining. The assumptions for the present research were based on the hypothesis that thin metal interlayers will behave as shear stress sinkers, which could decrease the delamination of the thin films. In the present work, coatings of TiAlN with thin ductile metallic interlayers (Al, Ti, Cu and Ag) were deposited by reactive d.c. magnetron sputtering. Multilayer coatings with aluminum, titanium and silver interlayers achieve higher adhesion values (70N) than TiAlN monolithic coating (40N). Three and five metal ductile layers contribute to an increase of hardness and Young's modulus without change the residual stresses of the monolithic coating. Contrarily, the introduction of copper layers reduces all the studied mechanical properties of the TiAlN monolithic coatings, which are related to the different deformation mechanisms of the ductile interlayers.

scholarly journals Mechanical properties of graphene oxide–silk fibroin bionanofilms via nanoindentation experiments and finite element analysis

Friction ◽  
2021 ◽  
Author(s):  
Hyeonho Cho ◽  
Joonho Lee ◽  
Hyundo Hwang ◽  
Woonbong Hwang ◽  
Jin-Gyun Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Graphene Oxide ◽  
Water Vapor ◽  
Silk Fibroin ◽  
Annealing Process ◽  
Indentation Modulus ◽  
Element Analysis ◽  
Vapor Annealing

AbstractUnderstanding the mechanical properties of bionanofilms is important in terms of identifying their durability. The primary focus of this study is to examine the effect of water vapor annealed silk fibroin on the indentation modulus and hardness of graphene oxide–silk fibroin (GO–SF) bionanofilms through nanoindentation experiments and finite element analysis (FEA). The GO–SF bionanofilms were fabricated using the layer-by-layer technique. The water vapor annealing process was employed to enhance the interfacial properties between the GO and SF layers, and the mechanical properties of the GO–SF bionanofilms were found to be affected by this process. By employing water vapor annealing, the indentation modulus and hardness of the GO–SF bionanofilms can be improved. Furthermore, the FEA models of the GO–SF bionanofilms were developed to simulate the details of the mechanical behaviors of the GO–SF bionanofilms. The difference in the stress and strain distribution inside the GO–SF bionanofilms before and after annealing was analyzed. In addition, the load-displacement curves that were obtained by the developed FEA model conformed well with the results from the nanoindentation tests. In summary, this study presents the mechanism of improving the indentation modulus and hardness of the GO–SF bionanofilms through the water vapor annealing process, which is established with the FEA simulation models.

Reasonable Value of Graded Macadam Base's Modulus

2013 ◽  
Vol 700 ◽  
pp. 225-228
Author(s):  
Fang Wang ◽  
Kai Liu ◽  
Yuan Rong Wang ◽  
Hai Yun Gao ◽  
Wei Hua Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Shear Stress ◽  
Asphalt Concrete ◽  
Rigid Base ◽  
Concrete Layer ◽  
Road Grade ◽  
Surface Deflection ◽  
Layer Position

Finite element method is employed to analyse tensile stress at the bottom of asphalt concrete layer and semi-rigid base, tension strain, road surface deflection and shear stress in asphalt concrete layer. The influence of graded macadam bases modulus on mechanical properties is studied. Meanwhile considering field modulus test values, reasonable value of graded macadam bases modulus, which is suitable for each road grade and each layer position, is proposed.

Mechanical Characterization of Biological Tissue: Finite Element Modeling

2010 ◽  
Author(s):  
Yue Xuan ◽  
Wei Tong
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Finite Element ◽  
Soft Tissue ◽  
Contact Area ◽  
Soft Tissues ◽  
Surface Deformation ◽  
Indentation Test ◽  
Biological Tissues ◽  
Test System

Indentation, in addition to the traditional tensile testing, has been widely used for evaluating mechanical properties of hard materials such as metals and bone as well as soft materials like polymer and soft tissues. However, it is difficult to measure the contact area and surface deformation in conventional indentation tests of soft tissue which will bring large errors to the evaluation of the material properties. Also the assumption of isotropic property limited the usage of indentation test in characterizing the nonlinear, anisotropic properties of soft tissue thin film. In this project, 2D and 3D finite element analyses has been carried out to predict hyperelastic material response under indentation and punch tests. A novel indentation test system was developed, which made the direct measurement of local deformation and contact area possible. The apparatus consists of a transparent indenter, a digital microscope, and a computer based control and data acquisition system. The proposed testing system and associated finite element analysis are used to characterize the mechanical properties of multiscale (bulk and thin film) biological tissues.

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