Constitutive relationship of brittle rock subjected to dynamic uniaxial tensile loads with microcrack interaction effects

2009 ◽  
Vol 52 (3) ◽  
pp. 140-145 ◽  
Author(s):  
X.P. Zhou ◽  
X.H. Li
Keyword(s):  
Interaction Effects ◽  
Brittle Rock ◽  
Constitutive Relationship ◽  
Uniaxial Tensile ◽  
Microcrack Interaction ◽  
Relationship Of

Constitutive Relationship of TRIP780 Steel in Quenching Process

2012 ◽  
Vol 572 ◽  
pp. 261-266
Author(s):  
Qiang Cao ◽  
Qing Dong Zhang ◽  
Chao Yang Sun
Keyword(s):  
Flow Stress ◽  
Tensile Tests ◽  
Constitutive Relationship ◽  
Uniaxial Tensile ◽  
Proposed Model ◽  
Quenching Process ◽  
Gleeble 3500 ◽  
Increasing Temperature ◽  
Relationship Of ◽  
The Impact

To characterize the mechanical behavior of TRIP780 steel in quenching process, Uniaxial tensile tests are performed on Gleeble-3500 thermo-simulation machine at temperature 323K~1073K and corresponding stress-strain curves are obtained. The results show that flow stress is affected by deformation temperature significantly and declines with increasing temperature. Based on simplified and modified Zerrilli-Armstrong model, the impact factor of temperature with quadratic polynomial fitting is introduced and the constitutive relationships with temperature dependent are established. The accuracy of the constitutive equations is verified and the flow stress predicted by the proposed model is consistent with experimental results. Therefore, the constitutive model can be applied for numerical simulation of quenching process.

The Sharp Indentation for Identifying Constitutive Relationship of Metallic Materials

2011 ◽  
Vol 117-119 ◽  
pp. 101-107
Author(s):  
Bo Yao ◽  
Li Xun Cai ◽  
Chen Bao
Keyword(s):  
Finite Element ◽  
Constitutive Relationship ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Metallic Materials ◽  
Test Results ◽  
Indentation Method ◽  
Sharp Indentation ◽  
Relationship Of ◽  
Constitutive Parameters

Based on a series of tests and elastic-plastic contact finite element analyses, a sharp indentation method for predicting the constitutive relationship of metallic materials was presented. Dependent on the dimensionless linear relationship which is independent of the hardening index n, a forecasting formula of constitutive parameters can be gotten and its form is much terser. The test results and finite element calculations show that, the predicted stress-strain curves are in agreement with the uniaxial tensile test results. The validity and precision of this method was certified by in-dentation tests on kinds of different materials.

The MHD Flows for a Heated Generalized Oldroyd-B Fluid With Fractional Derivative

2010 ◽  
Author(s):  
Yaqing Liu ◽  
Liancun Zheng ◽  
Xinxin Zhang ◽  
Fenglei Zong
Keyword(s):  
Fractional Calculus ◽  
Viscoelastic Fluid ◽  
Mhd Flow ◽  
Hankel Transform ◽  
Constitutive Relationship ◽  
Temperature Fields ◽  
Fractional Partial Differential Equations ◽  
Relation Model ◽  
Velocity And Temperature Fields ◽  
Relationship Of

In this paper, we present a circular motion of magnetohydrodynamic (MHD) flow for a heated generalized Oldroyd-B fluid. The fractional calculus approach is introduced to establish the constitutive relationship of a viscoelastic fluid. The velocity and temperature fields of the flow are described by fractional partial differential equations. Exact analytical solutions of velocity and temperature fields are obtained by using Hankel transform and Laplace transform for fractional calculus. Results for ordinary viscous flow are deduced by making the fractional order of differential tend to one and zero. It is shown that the fractional constitutive relation model is more useful than the conventional model for describing the properties of viscoelastic fluid.

scholarly journals Simulating the Stress-Strain Relationship of Geomaterials by Support Vector Machine

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hongbo Zhao ◽  
Zenghui Huang ◽  
Zhengsheng Zou
Keyword(s):  
Support Vector Machine ◽  
Constitutive Relationship ◽  
Support Vector ◽  
Nonlinear Relationship ◽  
Ann Model ◽  
Stress Strain ◽  
Svm Model ◽  
Strain Relationship ◽  
Artificial Neural Network Ann ◽  
Relationship Of

Stress-strain relationship of geomaterials is important to numerical analysis in geotechnical engineering. It is difficult to be represented by conventional constitutive model accurately. Artificial neural network (ANN) has been proposed as a more effective approach to represent this complex and nonlinear relationship, but ANN itself still has some limitations that restrict the applicability of the method. In this paper, an alternative method, support vector machine (SVM), is proposed to simulate this type of complex constitutive relationship. The SVM model can overcome the limitations of ANN model while still processing the advantages over the traditional model. The application examples show that it is an effective and accurate modeling approach for stress-strain relationship representation for geomaterials.

scholarly journals Structural Safety Evaluation of Tunnel Based on the Dynamic Monitoring Data during Construction

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaokun Yan ◽  
Hu Li ◽  
Feng Liu ◽  
Yang Liu
Keyword(s):  
Safety Evaluation ◽  
Constitutive Relationship ◽  
Monitoring Data ◽  
Dynamic Monitoring ◽  
Structural Safety ◽  
Underground Excavation ◽  
Tunnel Excavation ◽  
Evaluation Approach ◽  
Relationship Of ◽  
Shallow Buried Tunnel

It is still a challenge to accurately evaluate the structural safety of tunnel during the process of construction. To address this issue, a safety evaluation approach of tunnel based on the monitoring data during construction is proposed in this study. Firstly, the detailed description of modelling the tunnel excavation, releasing the load acting on the tunnel, and selecting the constitutive relationship of surrounding rock of tunnel is introduced. Secondly, aiming at an actual shallow-buried tunnel with underground excavation, utilizing the analytical results of deformation of tunnel, the structural safety of tunnel is evaluated by using a reliability-based method. Finally, the effectiveness of the proposed method is demonstrated by using the dynamic monitoring data obtained during the construction of an actual tunnel.

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