Elastoplastic behavior of the metal matrix nanocomposites containing carbon nanotubes: A micromechanics-based analysis

2017 ◽  
Vol 233 (4) ◽  
pp. 676-686 ◽  
Author(s):  
M Haghgoo ◽  
R Ansari ◽  
MK Hassanzadeh-Aghdam ◽  
A Darvizeh
Keyword(s):  
Carbon Nanotubes ◽  
Volume Fraction ◽  
Micromechanical Model ◽  
Strain Curve ◽  
Successive Approximation Method ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Elastoplastic Behavior ◽  
Metal Matrix Nanocomposites ◽  
Elastoplastic Stress

The elastoplastic behavior of aluminum (Al) nanocomposites reinforced with aligned carbon nanotubes (CNTs) is characterized using a unit cell micromechanical model. The interphase zone caused by the chemical reaction between CNT and Al matrix is included in the analysis. To attain the elastoplastic stress–strain curve of the nanocomposites, the successive approximation method together with the von Mises yield criterion is employed. The effects of several important factors including the volume fraction and diameter of CNT, material properties, and size of interphase on the elastoplastic stress–strain curve of the nanocomposites during uniaxial tension are studied. The results indicate that the interphase characteristics significantly affect the elastoplastic behavior of the CNT-reinforced Al nanocomposites. It is also found that the yield stress of the nanocomposites rises with increasing CNT volume fraction or decreasing CNT diameter. Besides, the elastoplastic stress–strain curve of the CNT-reinforced Al nanocomposites is presented for multiaxial tension. The initial yield envelopes of the nanocomposites under longitudinal–transverse biaxial tension are provided too. Comparison between the elastic results of the present model with those of other available micromechanical analyses shows a very good agreement.

Polypropylene Fiber Reinforced Concrete for Airfield Pavements:Modeling of Stress-Strain Curve Under Compression

2011 ◽  
Vol 261-263 ◽  
pp. 171-177
Author(s):  
Tammam Merhej ◽  
De Cheng Feng
Keyword(s):  
Reinforced Concrete ◽  
Analytical Model ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Polypropylene Fiber Reinforced Concrete

An analytical model for compressive stress-strain curve of polypropylene fiber reinforced concrete (PPFRC) was proposed. The polypropylene fiber used was 60-mm long twisted fiber with aspect ratio of 120. The fiber was added in three volume fractions 0.2%, 0.4% and 0.6%. Tow concrete mixtures with varying water-cement ratio were used. The accuracy of the proposed model was evaluated by comparing the area under stress-strain curves for experimental and analytical model. The results showed good agreement between the experimental and analytical curves. In addition; empirical equations were proposed to quantify the effect of polypropylene fiber on compressive strength, strain at peak stress, and toughness of concrete in terms of fiber volume fraction.

Experimental Research on Stress-Strain Curve of Carbon Fiber Reinforced Concrete

2013 ◽  
Vol 668 ◽  
pp. 640-644 ◽  
Author(s):  
Xiao Chu Wang ◽  
Jun Wei Wang ◽  
Hong Tao Liu
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Fiber Volume ◽  
Stress Strain

In order to further investigate the stress-strain curve of carbon fiber reinforced concrete, the curve of stress-strain is used segmentation tabulators on the basis of the existing tests. Based on the axial compression experiments of 9 carbon fiber concrete reinforced samples filled with different carbon fiber admixture amounts, the theoretical calculating formula of the stress-strain curve with different admixture amounts was proposed, and the theoretical formula of calculation parameters and carbon fiber volume fraction was putted forward. The experimental results show that the calculation parameters of the stress-strain curve increases with the increase of the carbon fiber admixture amounts. The theoretical calculating formula of the peak strain and carbon fiber volume fraction, the compressive strength, and the calculated results agreed well with the experimental results.

Multi-Phase-Field Analysis of Stress–Strain Curve and Ferrite Grain Formation during Dynamic Strain-Induced Ferrite Transformation

2014 ◽  
Vol 626 ◽  
pp. 81-84
Author(s):  
Akinori Yamanaka ◽  
Tomohiro Takaki
Keyword(s):  
Flow Stress ◽  
Phase Field ◽  
Volume Fraction ◽  
Strain Curve ◽  
Dynamic Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Ferrite Transformation ◽  
Multi Phase ◽  
Strain Induced Ferrite Transformation

A numerical model of dynamic strain-induced ferrite transformation (DSFT) was developed by combining the multi-phase field model with the Kocks–Mecking model. Using the developed model, a three-dimensional simulation of the DSFT in a Fe-C alloy was performed to study the correlation between the variation in flow stress and the microstructure evolution during the DSFT. The simulation results indicated that the developed model successfully simulated the characteristic DSFT behavior, i.e., both the stress–strain curve with a single peak and the formation of an ultrafine-grained ferrite microstructure. The variation in the flow stress during the DSFT was characterized by the volume fraction of the ferrite phase.

scholarly journals A Numerical Study on the Progressive Failure of 3D Four-Directional Braided Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Kun Xu
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Damage Accumulation ◽  
Numerical Study ◽  
Micromechanical Model ◽  
Strain Curve ◽  
Braided Composites ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
3D Braided Composites

The complexity of the microstructure makes the strength prediction and failure analysis of 3D braided composites difficult. A new unit cell geometrical model, taken as the representative volume element (RVE), is proposed to describe the yarn configuration of 3D braided composites produced by the four-step 1 × 1 method. Then, based on the periodical boundary conditions, a RVE-based micromechanical model by using the nonlinear finite element method has been presented to predict the progressive damage and the strength of 3D braided composites subjected to tensile loading. The numerical model can simulate the effect of damage accumulation on the tensile stress-strain curve by combining the proposed failure criteria and the stiffness degradation model. The longitudinal shear nonlinearity of braiding yarn is considered in the model. To verify the model, two specimens with typical braiding angles were selected to conduct the simulations. The predicted stress-strain curves by the model compared favorably with the experimental data, demonstrating the applicability of the micromechanical finite element model. The effect of the nonlinear shear parameter on the tensile stress-strain curve was discussed in detail. The results indicate that the tensile mechanical behaviors of 3D braided composites are affected by both the yarn shear nonlinearity and the damage accumulation.

A modified version of MATLAB application window for predicting the weld bead profile and stress–strain plot of AA5052 CMT weldment using ER4043

SIMULATION ◽  
2021 ◽  
pp. 003754972110315
Author(s):  
B Girinath ◽  
N Siva Shanmugam
Keyword(s):  
Strain Curve ◽  
Weld Bead ◽  
Welding Parameters ◽  
Bead Geometry ◽  
Hybrid Technique ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Weld Bead Geometry ◽  
Inference System ◽  
Engineering Stress

The present study deals with the extended version of our previous research work. In this article, for predicting the entire weld bead geometry and engineering stress–strain curve of the cold metal transfer (CMT) weldment, a MATLAB based application window (second version) is developed with certain modifications. In the first version, for predicting the entire weld bead geometry, apart from weld bead characteristics, x and y coordinates (24 from each) of the extracted points are considered. Finally, in the first version, 53 output values (five for weld bead characteristics and 48 for x and y coordinates) are predicted using both multiple regression analysis (MRA) and adaptive neuro fuzzy inference system (ANFIS) technique to get an idea related to the complete weld bead geometry without performing the actual welding process. The obtained weld bead shapes using both the techniques are compared with the experimentally obtained bead shapes. Based on the results obtained from the first version and the knowledge acquired from literature, the complete shape of weld bead obtained using ANFIS is in good agreement with the experimentally obtained weld bead shape. This motivated us to adopt a hybrid technique known as ANFIS (combined artificial neural network and fuzzy features) alone in this paper for predicting the weld bead shape and engineering stress–strain curve of the welded joint. In the present study, an attempt is made to evaluate the accuracy of the prediction when the number of trials is reduced to half and increasing the number of data points from the macrograph to twice. Complete weld bead geometry and the engineering stress–strain curves were predicted against the input welding parameters (welding current and welding speed), fed by the user in the MATLAB application window. Finally, the entire weld bead geometries were predicted by both the first and the second version are compared and validated with the experimentally obtained weld bead shapes. The similar procedure was followed for predicting the engineering stress–strain curve to compare with experimental outcomes.

Stress-strain curve of paper revisited

2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland
Keyword(s):  
Three Dimensional ◽  
Strain Curve ◽  
Failure Behavior ◽  
Three Dimensional Model ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fiber Network ◽  
Bonding Parameters ◽  
Particle Level ◽  
The Impact

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.

Definition of the yield point in plasticity and its effect on the shape of the yield locus

1966 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
T C Hsu
Keyword(s):  
Yield Point ◽  
Experimental Work ◽  
Strain Curve ◽  
Yield Locus ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Proportional Limit ◽  
Stress Strain ◽  
Small Section ◽  
Definition Of

Three different definitions of the yield point have been used in experimental work on the yield locus: proportional limit, proof strain and the ‘yield point’ by backward extrapolation. The theoretical implications of the ‘yield point’ by backward extrapolation are examined in an analysis of the loading and re-loading stress paths. It is shown, in connection with experimental results by Miastkowski and Szczepinski, that the proportional limit found by inspection is in fact a point located by backward extrapolation based on a small section of the stress-strain curve, near the elastic portion of the curve. The effect of different definitions of the yield point on the shape of the yield locus and some considerations for the choice between them are discussed.

Identification of post-necking stress–strain curve for sheet metals by inverse method

2016 ◽  
Vol 92 ◽  
pp. 107-118 ◽  
Author(s):  
Kunmin Zhao ◽  
Limin Wang ◽  
Ying Chang ◽  
Jianwen Yan
Keyword(s):  
Inverse Method ◽  
Strain Curve ◽  
Sheet Metals ◽  
Stress Strain Curve ◽  
Stress Strain
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