Effect of Interlayer on the Elastic-Plastic Deformation of Coating Systems

2019 ◽  
Vol 35 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Y. X. Guo ◽  
Y. W. Zhao
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Tensile Stress ◽  
Maximum Shear Stress ◽  
Indentation Load ◽  
Interlayer Thickness ◽  
The Finite Element Method ◽  
Thickness Increase ◽  
Elastic Plastic

ABSTRACTThe finite element method (FEM) was used to study the elastic-plastic contact in the coating systems with interlayer. The results reveal that with the increase of interlayer thickness, the maximum shear stress of coating/interlayer and interlayer/substrate interfaces decreases. Moreover, the sharply changed shear stress between the interfaces of coating/interlayer and interlayer/substrate decreases too. There is no further decrease when interlayer thickness increase to 0.04 mm and above. With the increasing of interlayer elastic modulus, the shear stress of coating/interlayer interface decreases while the shear stress of interlayer/substrate interface increases. Meanwhile, the higher elastic modulus leads to the intensive tensile stress concentration on the interface of coating/interlayer. Hence, the interlayer with appropriate elastic modulus not only reduces the shear stress of coating/interlayer and interlayer/substrate interfaces but also decreases the tensile stress of coating/interlayer interface. The mechanical properties of coating systems were investigated with different interlayer yield strength. The effective hardness and elastic modulus increase with the increase of interlayer yield strength, which is good to protect the substrate from the deformation. In addition, higher indentation load can lead to the decrease of effective hardness and elastic modulus.

The Force Impact Analysis of Steel Bridge Deck Pavement Layer Modulus and Pavement Thickness to Pavement System

2011 ◽  
Vol 368-373 ◽  
pp. 289-292
Author(s):  
San Qiang Yang ◽  
Pei Wen Hao ◽  
Li Qun Tang ◽  
Tao Liu
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Tensile Stress ◽  
Bridge Deck ◽  
Maximum Shear Stress ◽  
Maximum Tensile Stress ◽  
Steel Bridge ◽  
Epoxy Asphalt ◽  
Pavement Thickness ◽  
Bridge Deck Pavement

This epoxy asphalt used by the U.S., Japan Epoxy Asphalt two steel bridge deck pavement materials at different thickness analysis of pavement deformation force. Pavement derived the maximum tensile stress, shear stress and elastic modulus, pavement thickness of mathematical models. The results showed that: Pavement maximum tensile stress, shear stress, pavement elastic modulus with available four times a polynomial equation fitted, pavement surface transverse maximum stress increases as the pavement thickness decreases, horizontal maximum shear stress between layers does not increase with the pavement thickness decreases, but the thickness of the pavement at 40-50mm have a peak, then gradually increases with the thickness decreases.

Analysis of Performance Decay Behavior for Asphalt Pavement Based on Aging

2013 ◽  
Vol 723 ◽  
pp. 22-26 ◽  
Author(s):  
Pei Long Li ◽  
Zhan Ding ◽  
Zheng Qi Zhang
Keyword(s):  
Shear Stress ◽  
Service Life ◽  
Tensile Stress ◽  
Simulation Analysis ◽  
Asphalt Pavement ◽  
Maximum Shear Stress ◽  
Maximum Tensile Stress ◽  
Pavement Structure ◽  
Analysis Of Performance ◽  
Decay Behavior

Aging is a main factor affecting the durability of asphalt pavement. To study decay behavior of asphalt pavement with aging, aged asphalt was extracted from stratified pavement mixtures for different service-life. The changes of asphalt properties with service time and depth variations of the pavement were discussed. And numerical simulation analysis of pavement structure was conducted with pavement gradient modulus changes caused by aging. The results indicate that asphalt stiffness increases and low-temperature performance decays sharply with the extension of pavement service life, especially in the first several years. The vertical aging differences from top to bottom of pavement were significant, the aging extents decrease continuously from the surface, which cause the gradient changes of pavement modulus. The maximum tensile stress and maximum shear stress all increase with surface modulus increasing, so more serious aging can induce greater gradient modulus, shear stress and tensile stress are larger under the same loads, which have more serious damage to the pavement structure.

Contact Stress Analysis of NCD Coating on Cemented Carbide

2010 ◽  
Vol 431-432 ◽  
pp. 98-101
Author(s):  
Jia Jing Yuan ◽  
Wen Zhuang Lu ◽  
Dun Wen Zuo ◽  
Feng Xu
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Stress Distribution ◽  
Film Thickness ◽  
Contact Stress ◽  
Maximum Shear Stress ◽  
Shear Stress Distribution ◽  
Cemented Carbide ◽  
Low Elastic Modulus ◽  
Film Layer

The contact stress of cemented carbide with NCD coating in elastic contact was analyzed using ANSYS. Factors such as elastic modulus and thickness of NCD film and elastic modulus of interlayer which affect the shear stress distribution of NCD film on cemented carbide substrate were investigated. The results show that the maximum shear stress point moves towards the interface with the increase of film elastic modulus. Film thickness has a significant effect on shear stress distribution of NCD film. High shear stress develops in the film layer with the increase of film thickness. Interlayer with low elastic modulus will cause shear stress concentration in NCD film.

Influences of stress on the measurement of mechanical properties using nanoindentation: Part II. Finite element simulations

1996 ◽  
Vol 11 (3) ◽  
pp. 760-768 ◽  
Author(s):  
A. Bolshakov ◽  
W. C. Oliver ◽  
G. M. Pharr
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Contact Area ◽  
Cylindrical Specimen ◽  
Preceding Paper ◽  
Indentation Load ◽  
The Finite Element Method ◽  
Indentation Process ◽  
Plastic Indentation ◽  
Area Determination

The finite element method has been used to study the behavior of aluminum alloy 8009 during elastic-plastic indentation to establish how the indentation process is influenced by applied or residual stress. The study was motivated by the experiments of the preceding paper which show that nanoindentation data analysis procedures underestimate indentation contact areas and therefore overestimate hardness and elastic modulus in stressed specimens. The NIKE2D finite element code was used to simulate indentation contact by a rigid, conical indenter in a cylindrical specimen to which biaxial stresses were applied as boundary conditions. Indentation load-displacement curves were generated and analyzed according to standard methods for determining hardness and elastic modulus. The simulations show that the properties measured in this way are inaccurate because pileup is not accounted for in the contact area determination. When the proper contact area is used, the hardness and elastic modulus are not significantly affected by the applied stress.

Mechanical behavior assessment of sucrose using nanoindentation

2007 ◽  
Vol 22 (7) ◽  
pp. 2037-2045 ◽  
Author(s):  
K.J. Ramos ◽  
D.F. Bahr
Keyword(s):  
Experimental Study ◽  
Plastic Deformation ◽  
Shear Stress ◽  
Elastic Modulus ◽  
Slip System ◽  
Single Crystals ◽  
Maximum Shear Stress ◽  
Model Material ◽  
Instrumented Indentation ◽  
Plastic Properties

An experimental study of the elastic and plastic properties of sucrose single crystals, which can be considered to be a model material for both pharmaceutical excipients and explosives, has been carried out using nanoindentation. Instrumented indentation was used to characterize the properties of both habit and cleavage planes on the (100) and (001) orientations; the elastic modulus on the (100) is 38 GPa, while the modulus on the (001) is 33 GPa. The hardness of sucrose is approximately 1.5 GPa. Nanoindentation enables assessment of the onset of plastic deformation on cleaved surfaces, and a maximum shear stress of 1 GPa can be supported prior to plastic deformation. The deformation in this material is crystallographically dependent, with pileup around residual indentation impressions showing evidence of preferential slip system activity.

Effect of Matching Performance on J-Integral of Inhomogeneous Welded Joints

2012 ◽  
Vol 503-504 ◽  
pp. 568-571
Author(s):  
Bo He ◽  
Hong Cai Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Engineering Design ◽  
Welded Joints ◽  
Welded Joint ◽  
J Integral ◽  
The Finite Element Method ◽  
Matching Performance

In this paper, J-integral of 3-zone inhomogeneous welded joint is calculated by use of the finite element method, and the impacts of yield strength matching factor and elastic modulus matching factor on J-integral are studied as well. The analysis results show that the yield strength matching factor affects J-integral value greatly, that is, low matching of inhomogeneous welded joint of same steel can help to improve the ductility of the welded joint and the influence of yield strength matching factor on J-integral is much greater than that of elastic modulus matching factor, so it plays a very important role in the engineering design.

Analysis of the spherical indentation cycle for elastic–perfectly plastic solids

2004 ◽  
Vol 19 (12) ◽  
pp. 3641-3653 ◽  
Author(s):  
L. Kogut ◽  
K. Komvopoulos
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Material Properties ◽  
Deformation Behavior ◽  
Plastic Material ◽  
Elastic Plastic ◽  
Loading And Unloading ◽  
Elastic Plastic Material

A finite element analysis of frictionless indentation of an elastic–plastic half-space by a rigid sphere is presented and the deformation behavior during loading and unloading is examined in terms of the interference and elastic–plastic material properties. The analysis yields dimensionless constitutive relationships for the normal load, contact area, and mean contact pressure during loading for a wide range of material properties and interference ranging from the inception of yielding to the initiation of fully plastic deformation. The boundaries between elastic, elastic–plastic, and fully plastic deformation regimes are determined in terms of the interference, mean contact pressure, and reduced elastic modulus-to-yield strength ratio. Relationships for the hardness and associated interference versus elastic–plastic material properties and truncated contact radius are introduced, and the shape of the plastic zone and maximum equivalent plastic strain are interpreted in light of finite element results. The unloading response is examined to evaluate the validity of basic assumptions in traditional indentation approaches used to measure the hardness and reduced elastic modulus of materials. It is shown that knowledge of the deformation behavior under both loading and unloading conditions is essential for accurate determination of the true hardness and reduced elastic modulus. An iterative approach for determining the reduced elastic modulus, yield strength, and hardness from indentation experiments and finite element solutions is proposed as an alternative to the traditional method.

The Initiation and Propagation of Fatigue Cracks in Mild Steel Pieces of Square Section

1954 ◽  
Vol 4 (1) ◽  
pp. 1-18 ◽  
Author(s):  
H. L. Cox ◽  
J. E. Field
Keyword(s):  
Shear Stress ◽  
Tensile Stress ◽  
Mild Steel ◽  
Fatigue Cracks ◽  
Maximum Shear Stress ◽  
Shear Stresses ◽  
High Shear ◽  
Stress Range ◽  
High Shear Stress ◽  
General Direction

SummaryAn investigation has been made to determine the positions and directions of initiation and the directions of propagation of fatigue cracks and to examine the correlation between these positions and directions and the planes on which maximum tensile and maximum shear stresses are generated.To afford as wide a range as possible of the ratio of maximum shear stress to maximum tensile stress, tests have been made under combinations of alternating bending and torsion; and in order to separate partially the regions of high shear stress from those of high direct stress, the tests have been made on pieces of square section with the plane of bending parallel to one diagonal of the section. Two series of tests have been made; one a preliminary series on pieces having no parallel portion and the other on pieces having a parallel portion about three times the length of the side of the square section. The positions and directions of initiation and the directions of propagation of fatigue cracks have been observed and compared with the positions and directions of the maximum tensile and shear stresses.Fatigue cracks may be initiated as a result of either high shear stress or high tensile stress and in the present series of tests on mild steel, cracking in tension has occurred in preference to cracking in shear when the ratio of the tensile stress range to the shear stress range has exceeded about 1.6; for values of this ratio less than 1.6, the cracks started in shear (and vice versa); propagation along the plane of maximum shear appears to be preferred up to a slightly greater value of the tensile/shear ratio (about 1.7 possibly). The general direction of a crack formed as a result of high tension usually follows the plane of maximum tension and that of a crack formed as a result of shear usually follows the plane of maximum shear. In detail both types of crack—in this mild steel—deviate quite widely from their general directions but this deviation bears no obvious relation to the microstructure of the material. Cracks propagating along one plane of maximum shear occasionally show a marked tendency to branch along the associated plane of maximum shear; but this tendency is not always observed and in other cases no tendency to branch has been noted.

Contact Stress Analysis During Fretting of a Surface Modified Flat-on-Flat With Round Edge

2019 ◽  
Author(s):  
Pankaj Dhaka ◽  
Raghu V. Prakash
Keyword(s):  
Elastic Modulus ◽  
Yield Strength ◽  
Tensile Stress ◽  
Surface Treatment ◽  
Contact Pressure ◽  
Normal Load ◽  
Contact Geometry ◽  
Parent Material ◽  
Tangential Displacement ◽  
Element Analysis

Abstract In the present work, a two-dimensional finite element analysis is carried out to understand the influence of contact geometry and surface treatment on the fretting behavior of a flat with round edge-on-flat plate contact. The fretting pad and plate are modeled using isotropic elastic material properties of Ti-6Al-4V. The mating pair was subjected to a constant normal load followed by a tangential displacement. The effect of contact geometry was studied by independently varying length of the central flat region and radii of corners. Parameters important from the context of fretting viz. contact pressure and normal stress (in tangential direction) were extracted. The effect of surface treatment was studied by modeling two layers of different elastic modulus and yield strength on the mating surfaces. It is found that addition of intermediate layers of lower elastic modulus and yield strength than the parent material leads to a reduction in both contact pressure and peak tensile stress; the influence was more on the peak tensile stress than contact pressure. Further, the addition of softer and less stiff layers on the pad is noted to be less advantageous than adding it on both pad and substrate or substrate only case. The study suggests that contact geometry should be taken into account while carrying out surface modifications of contact pairs.

Effect of Matrix Properties on Shear Stress in Composite Reinforced with W Fiber under Loading

2013 ◽  
Vol 401-403 ◽  
pp. 602-605
Author(s):  
Li Jun Zhu ◽  
Kai Wen Tian ◽  
Wen Lu Shi ◽  
Chao Yang ◽  
Zhen Ming Wang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Yield Strength ◽  
High Yield ◽  
Ansys Software ◽  
High Yield Strength ◽  
Low Elastic Modulus ◽  
Matrix Properties ◽  
The Matrix ◽  
Two Phases

The effect of yield strength and elastic modulus of matrix on shear stress in two phases of composite reinforced with W fiber under pulse loading was simulated by ANSYS software. The results show that the effect of mechanical properties of matrix on composite should be taken into consideration in designing composite. The matrix with high yield strength and low elastic modulus can reduce the shear stress in W fiber, and is beneficial to keeping the integrity of W fiber during penetration, thus resulting in the improvement of penetration capacity.

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