A Rate-Dependent Inelastic Constitutive Model—Part I: Elastic-Plastic Flow

1991 ◽  
Vol 113 (3) ◽  
pp. 314-323 ◽  
Author(s):  
F. Ellyin ◽  
Z. Xia
Keyword(s):  
Constitutive Model ◽  
Plastic Flow ◽  
Inelastic Deformation ◽  
Experimental Results ◽  
Elastic Plastic ◽  
Rate Dependent ◽  
Wide Range ◽  
Strain Stress ◽  
Standard Tests ◽  
Inelastic Processes

In this part a rate-dependent elastic-plastic constitutive model is presented which is an extension of our earlier rate-indpendent model. The effect of prior creep on the subsequent inelastic deformation is also included. The model can be used to predict inelastic processes with variable strain (stress) rates. It is shown, through comparison with the experimental results, that most of the rate-effect features of the material response can be simulated by the model. Despite the wide range of application, the model is relatively simple and incorporated a few material constants which could be easily determined from standard tests.

Plastic Flow Stress and Constitutive Model for H96 Brass Alloy

2015 ◽  
Vol 782 ◽  
pp. 130-136 ◽  
Author(s):  
Ping Zhou ◽  
Wei Guo Guo ◽  
Hai Hui Wu
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Plastic Flow ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Experimental Results ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Brass Alloy ◽  
Plastic Flow Stress

To explore the thermo-mechanical response of H96 brass alloy, the quasi-static (universal-testing machine) and dynamic (the split Hopkinson pressure bar apparatus) uniaxial compression experiments have been performed under the temperatures from 293 K to 873 K and the strain rates from 0.001 s-1 to 6000 s-1, and the strains over 60% are obtained. Results show that, H96 brass alloy has strong strain hardening behavior, and it becomes weaker with the increasing temperature. In addition, this alloy is sensitive to strain rates; and, it has temperature sensitivity, the dynamic strain aging occurs at the temperature of 473 K and a quasi-static strain rate of 0.001 s-1. Based on the thermal activation dislocation mechanism, paralleled with the experimental results, a plastic flow constitutive model with the physical conception is developed. The model is suitable to predict the plastic flow stress at different temperatures and strain rates. According to comparing results, the model predictions are in good agreement with the experimental results.

A Constitutive Model Research Based on Dislocation Mechanism of 5083 Aluminum Alloy

2017 ◽  
Vol 35 (02) ◽  
pp. 145-152
Author(s):  
N. Gao ◽  
Z. Zhu ◽  
S. Xiao ◽  
Q. Xie
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Plastic Flow ◽  
Test System ◽  
Dislocation Dynamics ◽  
Strain Rates ◽  
Prediction Ability ◽  
Yield Behavior ◽  
Wide Range ◽  
5083 Aluminum Alloy

ABSTRACTThe study of the mechanical properties of polycrystalline alloy materials under dynamic impact, namely, the prediction of mechanical behavior after yield stress and the establishment of a constitutive model, has attracted much attention in the field of engineering. The stress-strain curves of 5083 aluminum alloy were obtained under strain rates varying from 0.0002 s-1 to 7130 s-1 through uniaxial compression experiments. The equipment used included a CRIMS RPL100 tester, Instron tester, and split Hopkinson test system. In addition, based on dislocation dynamics and the strengthening mechanism of metals, the plastic flow of the 5083 aluminum alloy was systematically analyzed under a wide range of strain rates. It was found that the abnormal yield behavior of the 5083 aluminum alloy under a wide range of strain rates increased, and the experimental phenomenon of hardening rate decreased with an increase in strain rate. This study also revealed that the abnormal yield behavior is caused by the different dislocation mechanisms of two-phase alloy elements under different strain rates. Based on the thermal activation theory and the experimental data, a constitutive model was developed. A comparison showed good agreement between the experimental and model curves. This indicates that this model has good plastic flow stress prediction ability for such types of materials.

scholarly journals A New Rate-Dependent Constitutive Model of Superelastic Shape Memory Alloys and Its Simple Application in a Special Truss Moment Frame Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Maria I. Ntina ◽  
Dimitrios S. Sophianopoulos
Keyword(s):  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Experimental Results ◽  
Simple Application ◽  
Moment Frame ◽  
Rate Dependent ◽  
Ongoing Work ◽  
Good Agreement

In this work, a new constitutive model of the behavior of shape-memory alloys is presented, based on earlier models, showing a very good agreement with the existing experimental results. A simple approximate application concerning the use of these alloys modelled as dissipation devices in a special truss-moment frame is demonstrated. The results obtained are considered sufficiently encouraging as a motivation for the ongoing work.

Viscoelastic-viscoplastic combined constitutive model for glassy amorphous polymers under loading/unloading/no-load states

2020 ◽  
Vol 37 (5) ◽  
pp. 1703-1735
Author(s):  
Seishiro Matsubara ◽  
Kenjiro Terada ◽  
Ryusei Maeda ◽  
Takaya Kobayashi ◽  
Masanobu Murata ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Deformation Rate ◽  
Amorphous Polymers ◽  
Elastic Behavior ◽  
Content Type ◽  
Rate Dependent ◽  
Proposed Model ◽  
Wide Range ◽  
In Series ◽  
Rheology Model

Purpose This study aims to propose a novel viscoelastic–viscoplastic combined constitutive model for glassy amorphous polymers within the framework of thermodynamics at finite strain that is capable of capturing their rate-dependent inelastic mechanical behavior in wide ranges of deformation rate and amount. Design/methodology/approach The rheology model whose viscoelastic and viscoplastic elements are connected in series is set in accordance with the multi-mechanism theory. Then, the constitutive functions are formulated on the basis of the multiplicative decomposition of the deformation gradient implicated by the rheology model within the framework of thermodynamics. Dynamic mechanical analysis (DMA) and loading/unloading/no-load tests for polycarbonate (PC) are conducted to identify the material parameters and demonstrate the capability of the proposed model. Findings The performance was validated in comparison with the series of the test results with different rates and amounts of deformation before unloading together. It has been confirmed that the proposed model can accommodate various material behaviors empirically observed, such as rate-dependent elasticity, elastic hysteresis, strain softening, orientation hardening and strain recovery. Originality/value This paper presents a novel rheological constitutive model in which the viscoelastic element connected in series with the viscoplastic one exclusively represents the elastic behavior, and each material response is formulated according to the multiplicatively decomposed deformation gradients. In particular, the yield strength followed by the isotropic hardening reflects the relaxation characteristics in the viscoelastic constitutive functions so that the glass transition temperature could be variant within the wide range of deformation rate. Consequently, the model enables us to properly represent the loading process up to large deformation regime followed by unloading and no-load processes.

A Dynamic Elastic-Plastic Microplane Constitutive Model for Steel Fiber Reinforced Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 421-425
Author(s):  
Wei Xie ◽  
Ming Xiao Jia
Keyword(s):  
Reinforced Concrete ◽  
Constitutive Model ◽  
Steel Fiber ◽  
Failure Strain ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Plastic Model ◽  
Elastic Plastic ◽  
Shear Component ◽  
Strain Stress

A dynamic elastic-plastic microplane constitutive model for concrete based on M2 which is proposed by B.P. Bazant etc., is presented in this paper. The state of each microplane is characterized by normal deviatoric and volumetric strains and shear strain.The strain-stress relations for deviatoric and shear component is described as elastic-plastic model. A new concept: failure strain has been introduced. The stress shall be zero after the microplane stress reaches failure stain level. The reinforced effect of steel fiber on concrete is taken account in this paper. Finally 2 calculation examples have been adopted to verify the rationality and correctness of the proposed module.

A constitutive model for frozen soil based on rate-dependent damage evolution

2017 ◽  
Vol 27 (10) ◽  
pp. 1589-1600 ◽  
Author(s):  
Chenxu Cao ◽  
Zhiwu Zhu ◽  
Tiantian Fu ◽  
Zhijie Liu
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Frozen Soil ◽  
Experimental Results ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Dynamic Mechanical ◽  
Rate Dependent

The deformation of frozen soil under impact loading is usually accompanied by the evolution of internal defects and microdamage. By taking the strain and strain rates into account, a rate-dependent damage evolution law is proposed in this study, under the assumption of equivalent strain. Subsequently, a damage-modified rate-dependent constitutive model is proposed to describe the dynamic mechanical properties of frozen soil. A split Hopkinson pressure bar is utilized to test the dynamic mechanical response of frozen soil at different temperatures and high strain rates. The experimental results show that frozen soil produces obvious strain rate and temperature effects, and that there is a linear relationship between the peak stress and temperature. The theoretical results of the proposed constitutive model agree well with the experimental results, verifying the applicability of the model.

Study on the Constitutive Model of Composite Materials in Elastic-Plastic Stage

2012 ◽  
Vol 166-169 ◽  
pp. 73-77
Author(s):  
Huan Chao Qin ◽  
Ju Lin Wang
Keyword(s):  
Composite Materials ◽  
Theoretical Analysis ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Experimental Results ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Flexibility Matrix ◽  
Plastic Stage

Elastic-plastic properties of composite materials are an important part of the study on micromechanics. Based on the plastic strain of matrix, the elastic-plastic constitutive model of composite materials is presented in this paper, while considering the influence of the transient flexibility matrix on the flexibility matrix. In comparison with the experimental results, theoretical analysis of the presented model is validated.

The Improved Johnson-Cook’s Strength Model Taking Account of the Rate-Dependent Micro-Damage Evolution for C30 Concrete

2006 ◽  
Vol 326-328 ◽  
pp. 1101-1104
Author(s):  
Shao Chiu Shih ◽  
Yong Zhong Wang ◽  
Li Li Wang
Keyword(s):  
Damage Evolution ◽  
High Pressures ◽  
Engineering Application ◽  
Experimental Results ◽  
Rate Coefficients ◽  
Large Strains ◽  
Strain Rates ◽  
Strength Model ◽  
Rate Dependent ◽  
Wide Range

The dynamic mechanical behavior of C30 concrete under a wide range of strain rates from 10-4s-1 up to 102s-1 is studied. According to Johnson-Cook’s strength model, the strain rate coefficients and related material constants of C30 concrete subjected to large strains, high strain rates and high pressures are determined experimentally: C=0.34*10-1, A=1.05, B=1.65, N=0.76, TC =3.162MPa, fc’=39.2MPa. The damage evolution for C30 concrete is a rate-dependent process, which can be formulated to a rate-dependent damage evolution law in a simple form for engineering application. When ε > ε th, ( ) 1 D th D = K ε&α − ε −ε . The corresponding dynamic coefficients of C30 concrete are also obtained from impact experimental results: KD=530.2, a=0.83. Due to a<1, the damage evolution corresponds to an impact toughening process that coincide well with the dynamic experimental results for C30 concrete.

scholarly journals A NEW MODEL OF RATE DEPENDENT ELASTIC-PLASTIC FLOW

1992 ◽  
pp. 383-386 ◽  
Author(s):  
James E. HAMMERBERG ◽  
Dean L. PRESTON ◽  
Duane C. WALLACE
Keyword(s):  
Plastic Flow ◽  
New Model ◽  
Elastic Plastic ◽  
Rate Dependent
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