Using the elastic modulus defect for diagnostics of plastic deformation of metal

2020 ◽  
pp. 34-35
Author(s):  
M.M. Matlin ◽  
V.A. Kazankin ◽  
E.N. Kazankina ◽  
A.I. Mozgunova ◽  
A.I. Sotnikova

A non-destructive method for assessing the plastic deformation of a metal after processing a product is proposed, based on a change in the elastic properties of the material. Keywords metal, elastic properties, modulus of elasticity, Poisson's ratio, plastic deformation, non-destructive method, tension. [email protected]

Author(s):  
Min-Ki Cho ◽  
Chang-Hoon Ha ◽  
Moo-Yong Kim ◽  
Sang-Cheol Lee ◽  
Jea-Mean Koo ◽  
...  

A tube support plate is one of the significant parts of a steam generator, which confines the rotational and translational motion of tubes caused by the hydraulic and seismic load. It also provides a flow path along the tubes. There are various types of tube support plates according to the component designer’s preference. In this investigation, ten types of trefoil Broached Tube Support Plate (BTSP) specimens made from ASME stainless steel were analyzed and tested to determine the appropriate shape of trefoil BTSP in the view of the elastic properties including elastic modulus and Poisson’s ratio. The types of trefoil BTSP specimens were designated as SI through S5 and L1 through L5 for S and L types, respectively. These specimens are categorized by the shape and dimension of broached hole. Ten specimens were investigated through finite element analysis, and compression and bending tests. The dimensions of the test specimens were decided through a previous research study done to examine appropriate shape for the compression and bending tests. The equivalent elastic properties of BTSP were obtained by the finite element analysis as per different loading orientation as well as the various specimen types. Autodesk® Inventor™ software was used to make the analytical model and ABAQUS® software was used for the analysis and post-processing. The equivalent elastic properties of BTSP specimens were also acquired by the compression and bending tests. From the results of the finite element analysis, and the compression and bending tests, the appropriate shapes of trefoil BTSP with regard to the equivalent elastic modulus, and Poisson’s ratio are suggested as L4, S3, and S4.


2013 ◽  
Vol 868 ◽  
pp. 319-325 ◽  
Author(s):  
Yi Lei ◽  
Wen Bin Wu

Mathematical model based on elasticity is not suitable for soft seam hydraulic fracturing mechanism study because its intensity is small, Poisson's ratio is relatively large, and its prone to plastic deformation. Based on plastic mechanics, the theory of large deformation and fracture mechanics theory, hydraulic fracturing of soft coal seam is divided into three phases, namely, coal bed compaction, fracture initiation and crack propagation from the view of the deformation mechanism, the occurring and developing mechanism. The initiation pressure of soft seams considered strain softening character after plastic deformation is obtained on the basis of above. The result shows that the initiation pressure is related to elastic modulus, Poisson's ratio, the angle of internal friction and residual strength. Elastic modulus is inversely proportional to the initiation pressure, the greater its value, the smaller the initiation pressure; but Poisson's ratio, the angle of internal friction and the residual strength and fracture initiation pressure is directly proportional relationship, the greater its value, since the smaller the crack pressure.


2018 ◽  
Vol 29 (11) ◽  
pp. 2392-2405 ◽  
Author(s):  
Mohammad Kazem Hassanzadeh-Aghdam ◽  
Mohammad Javad Mahmoodi

In this article, a unit cell micromechanics model is developed to predict the elastic properties of shape memory polymer nanocomposites containing silica (SiO2) nanoparticles. The model incorporates an interphase zone corresponding to a perturbed region of shape memory polymer matrix around SiO2 nanoparticles. It is found that the elastic properties of shape memory polymer nanocomposites are significantly sensitive to the temperature in the presence of interphase region. As the temperature increases, the shape memory polymer nanocomposite elastic modulus decreases, while the normalized elastic modulus nonlinearly rises. The results reveal that Poisson’s ratio decreases nonlinearly with the increase of temperature. The shape memory polymer nanocomposite mechanical properties are significantly influenced by the nanoparticle diameter in the presence of interphase region. Substantial improvement in normalized elastic modulus is observed with reducing the nanoparticle diameter. Also, a nonlinear decrease in Poisson’s ratio is found as the nanoparticle diameter decreases. Furthermore, the role of nanoparticle diameter becomes more prominent due to enhancement of temperature. The results indicate that with increasing SiO2 nanoparticles’ volume fraction, the elastic modulus of shape memory polymer nanocomposite nonlinearly rises, while Poisson’s ratio decreases. Finally, it is shown that the increase of interphase thickness leads to the enhancement of normalized elastic modulus of shape memory polymer nanocomposite.


2021 ◽  
Vol 889 ◽  
pp. 163-170
Author(s):  
Praphulla K. Deshpande ◽  
Keshav K. Sangle ◽  
Yuwaraj M. Ghugal

The paper deals with the experimental and theoretical results of elastic constants of polymer modified high strength concrete with high fibre volume fraction. To evaluate elastic properties of this composite system, compressive and flexural strengths were obtained experimentally. Elastic properties such as modulus of elasticity and Poisson’s ratio are first obtained based on experimental results. Simplified equations based on micromechanics, and solid mechanics theories are utilized for the evaluation of elastic properties of polymer modified randomly oriented short steel fibre reinforced high strength concrete. The micromechanics equations for the modulus of elasticity and the Poisson’s ratio are based on the fibre volume fraction and the elastic moduli of the fibre and polymer modified concrete matrix. The existing empirical equations are also used to obtain elastic constants. These equations are applied in the full range of fiber volume fraction (1% to 10%). The comparison of experimental results with theoretical values shows the good agreement with each other. The novelty of the present paper is that the modulus of elasticity of this composite system is obtained experimentally using four point bending test and the Poisson’s ratio is obtained as a function of flexural and compressive strengths with excellent accuracy for the first time.


Author(s):  
P .S.K.Murthy ◽  
Sachin Gupta ◽  
Dhirendra Kumar ◽  
Mahabir Dixit

The interconnection of vesicles in basaltic flows greatly affects the engineering properties such as uniaxial compressive strength, modulus of elasticity, Poisson’s ratio, tensile strength and sonic velocities. Sometimes these vesicles are filled with secondary minerals such as quartz/olivine/calcite form as amygdules (which are impermeable). In the present study, to understand effect of porosity, vesicular and amygdular basaltic flows collected from central and west-central India were investigated for these engineering properties and correlated with apparent porosity of core samples. It is observed that a good level of correlation is obtained for uniaxial compressive strength (UCS), elastic modulus (E) and Poisson’s ratio in vesicular basalts when porosity >8-10%. In case of Brazilian strengths a linearly downward trend is observed with the increase in porosity values. And, no significant correlation is observed for waves’ velocities in both variants of basalts.


2013 ◽  
Vol 6 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ai Chi ◽  
Li Yuwei

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent cracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat. By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and butt cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially increased and then decreased with increasing of the face cleat inclination.


2021 ◽  
pp. 107754632110026
Author(s):  
Zhou Sun ◽  
Siyu Chen ◽  
Xuan Tao ◽  
Zehua Hu

Under high-speed and heavy-load conditions, the influence of temperature on the gear system is extremely important. Basically, the current work on the effect of temperature mostly considers the flash temperature or the overall temperature field to cause expansion at the meshing point and then affects nonlinear factors such as time-varying meshing stiffness, which lead to the deterioration of the dynamic transmission. This work considers the effect of temperature on the material’s elastic modulus and Poisson’s ratio and relates the temperature to the time-varying meshing stiffness. The effects of temperature on the elastic modulus and Poisson’s ratio are expressed as functions and brought into the improved energy method stiffness calculation formula. Then, the dynamic characteristics of the gear system are analyzed. With the bifurcation diagram, phase, Poincaré, and fast Fourier transform plots of the gear system, the influence of temperature on the nonlinear dynamics of the gear system is discussed. The numerical analysis results show that as the temperature increases, the dynamic response of the system in the middle-speed region gradually changes from periodic motion to chaos.


2020 ◽  
Vol 6 (1) ◽  
pp. 50-56
Author(s):  
Francesco Baino ◽  
Elisa Fiume

AbstractPorosity is known to play a pivotal role in dictating the functional properties of biomedical scaffolds, with special reference to mechanical performance. While compressive strength is relatively easy to be experimentally assessed even for brittle ceramic and glass foams, elastic properties are much more difficult to be reliably estimated. Therefore, describing and, hence, predicting the relationship between porosity and elastic properties based only on the constitutive parameters of the solid material is still a challenge. In this work, we quantitatively compare the predictive capability of a set of different models in describing, over a wide range of porosity, the elastic modulus (7 models), shear modulus (3 models) and Poisson’s ratio (7 models) of bioactive silicate glass-derived scaffolds produced by foam replication. For these types of biomedical materials, the porosity dependence of elastic and shear moduli follows a second-order power-law approximation, whereas the relationship between porosity and Poisson’s ratio is well fitted by a linear equation.


Author(s):  
Serge Abrate

The behavior of functionally graded structures has received a great deal of attention in recent years. Usually, these structures are made out of a composite material with a modulus of elasticity, a Poisson’s ratio, and a density that vary through the thickness. The non-uniformity through the thickness introduces coupling between the transverse deformations and the deformations of the mid-surface. Previous publications have shown how to account for these added complexities and have presented extensive results in tabular form. In this article, available results are used to show that the behavior of functionally graded shells is similar to that of homogeneous isotropic shells. It is well known that for isotropic shells, results can be presented in non-dimensional form so that, once results are obtained for one material, they can be simply scaled to obtain the corresponding results for shells made out of another material. The same can then be done for functionally graded shells. In addition, if functionally graded shells behave like homogeneous shells, no new method of analysis is required. The second part of the paper examines why this is true.


2021 ◽  
Author(s):  
Meng Meng ◽  
Luke Frash ◽  
James Carey ◽  
Wenfeng Li ◽  
Nathan Welch ◽  
...  

Abstract Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.


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