scholarly journals A Constitutive Model Incorporating Mixed Soil Slurry for Interface

2021 ◽  
Vol 276 ◽  
pp. 01021
Author(s):  
Kai Peng ◽  
Guohui Wang ◽  
Yaolai Liu ◽  
Xiaoliang Wang ◽  
Dong Liu ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Strain Softening ◽  
Cement Content ◽  
Experimental Tests ◽  
Coarse Grained ◽  
Model Parameters ◽  
Soil Slurry ◽  
Shear Tests ◽  
Generalized Potential Theory ◽  
Coarse Grained Soil

In projects, mixed soil slurry between cut-off wall and coarse-grained soil always exists. It may influence on or change mechanical properties of interface between coarse-grained soil and structure. The mechanical behaviors of the interface between coarse-grained soil and concrete were investigated by simple shear tests under mixed soil slurry. The significant dilatancy and stress-strain softening can be achieved through the results, which also indicate that the cement content play an important role in the shear strength of the interface. The peak strength and the position when the dilatancy occurs are related to both normal stress and cement content. An elasto-plastic constitutive model for interface considering mixed soil slurry was formulated in the framework of generalized potential theory. The entire model parameters can be identified by experimental tests. Finally, the predictions of the model have been compared with experimental results, and results show the model is reasonable and practical.

State of the Art of Constitutive Model of Concrete Materials Based on Damage Mechanics

2011 ◽  
Vol 194-196 ◽  
pp. 848-852
Author(s):  
Duo Xin Zhang ◽  
Qing Yun Wang
Keyword(s):  
Constitutive Model ◽  
Damage Mechanics ◽  
State Of The Art ◽  
Constitutive Models ◽  
Experimental Tests ◽  
Constitutive Relationship ◽  
Model Parameters ◽  
Softening Effect ◽  
Volumetric Expansion ◽  
Concrete Materials

This study centered on the development of constitutive model of the material based on damage mechanics. Volumetric expansion, unilateral behavior and softening effect have been pointed out as three difficulties during setting constitutive model of concrete, the applicable and deficiency of the existed constitutive relationship been reviewed, and the methods used to deal above difficulties were overviewed, Meanwhile, the background of existed model has been summarized and listed systematically. The development of a thermodynamic approach to constitutive model of concrete, with emphasis on the rigorous and consistency both in the formulation of constitutive models and in the identification of model parameters based on experimental tests has been potential direction of the future study, and hoped furnished basement for the elastic to plastic coupled damage mechanics constitutive model of concrete.

Experimental and Numerical Characterization of the Stress-Strain Behavior of Weak Sandstone Formations for Sanding Assessment

2018 ◽  
Author(s):  
Nubia Aurora González Molano ◽  
Jacobo Canal Vila ◽  
Héctor González Pérez ◽  
José Alvarellos Iglesias ◽  
M. R. Lakshmikantha
Keyword(s):  
Constitutive Model ◽  
Equivalent Plastic Strain ◽  
Experimental Tests ◽  
Thick Wall ◽  
Triaxial Tests ◽  
Experimental Program ◽  
Model Parameters ◽  
Sand Production ◽  
Strain Behavior ◽  
Weak Sandstone

In this study an extensive experimental program has been carried out in order to characterize the mechanical behavior of two weak sandstone formations of an offshore field for application to sand production modeling. The experimental tests included Scratch tests, Triaxial tests and Advanced thick wall cylinder tests (ATWC) where the sand production initiation and the cumulative sand produced were registered. Numerical simulations of experimental tests were then performed using an advanced elasto-plastic constitutive model. Triaxial tests simulations allowed calibrating the constitutive model parameters. These parameters were employed for the numerical simulation of the ATWC in order to determine the equivalent plastic strain threshold required to the onset of sand production observed in laboratory for sanding assessment. Results obtained highlight the importance to use a realistic representation of the rock behavior focusing on post-yield behavior in order to build confidence in model predictions.

Study on Statistical Damage Softening Constitutive Model and Determination of Parameters for Rock Based on Lognormal Distribution

2011 ◽  
Vol 69 ◽  
pp. 33-38
Author(s):  
Jian Hua Wen ◽  
Cui Ying Zhou ◽  
Li Huang ◽  
Ye Cheng ◽  
Lin Chong Huang ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Lognormal Distribution ◽  
Strain Softening ◽  
Model Parameters ◽  
Kolmogorov Smirnov ◽  
Random Distributions ◽  
Determination Of Parameters ◽  
Smirnov Test ◽  
Statistical Damage

Based on the property that micro-cells strength is consistent with lognormal distribution function, this paper presented a new statistical damage softening constitutive model simulating the full process of strain softening for rock. Through discussing the characteristics of random distributions for rock micro-cells strength, lognormal distribution assumption is tested by Kolmogorov-Smirnov test in statistics, and the reasonable method of geometry boundary condition is selected to determine model parameters that can be easily applied to the situations under different complex conditions. Gabbro experiment comparative analyses show that the new damage softening constitutive model is rational and convenient in engineering.

Statistical damage model with strain softening and hardening for rocks under the influence of voids and volume changes

2010 ◽  
Vol 47 (8) ◽  
pp. 857-871 ◽  
Author(s):  
Wen-Gui Cao ◽  
Heng Zhao ◽  
Xiang Li ◽  
Yong-Jie Zhang
Keyword(s):  
Constitutive Model ◽  
Strain Softening ◽  
Triaxial Compression ◽  
Damage Model ◽  
Damage Threshold ◽  
Model Parameters ◽  
Volume Changes ◽  
Conventional Triaxial Compression ◽  
Damage Constitutive Model ◽  
Statistical Damage

With regards to the composition of natural rocks including voids or pores, deformation behavior is strongly affected by variation in porosity. By using a statistical damage-based approach, the characteristics of strain softening and hardening under the influence of voids and volume changes are investigated in the present paper. Suppose that a rock consists of three parts: voids, a damaged part, and an undamaged part. The effects of voids and volume changes on rock behavior are first analyzed through determination of the porosity and an associated damage model is then developed. Later, a statistical evolution equation describing the influence of the damage threshold on the propagation condition of rock damage is formulated based on measurement of the mesoscopic element strength. A statistical damage constitutive model reflecting strain softening and hardening behavior for rocks loaded in conventional triaxial compression is further developed and a corresponding method for determining the model parameters is also provided. Theoretical results of this proposed model are then compared with those observed experimentally. Finally, several aspects of the present constitutive model, which affect the relevant behavior of rocks, are particularly discussed.

scholarly journals Study of Sericite Quartz Schist Coarse-Grained Soil by Large-Scale Triaxial Shear Tests

2020 ◽  
Vol 8 ◽  
Author(s):  
Hui-qing Zhang ◽  
Feng Zhao ◽  
Shi-qiang Cheng ◽  
Yan-qing Zhang ◽  
Ming-jie Gou ◽  
...  
Keyword(s):  
Large Scale ◽  
Coarse Grained ◽  
Shear Tests ◽  
Coarse Grained Soil

Inverse Identification of CDM Model Parameters for DP1000 Steel Sheets Using a Hybrid Experimental-Numerical Methodology Spanning Various Stress Triaxiality Ratios

2013 ◽  
Vol 554-557 ◽  
pp. 2103-2110 ◽  
Author(s):  
Zhen Ming Yue ◽  
Celal Soyarslan ◽  
Houssem Badreddine ◽  
Khemais Saanouni ◽  
A. Erman Tekkaya
Keyword(s):  
Constitutive Model ◽  
Pure Shear ◽  
Stress Triaxiality ◽  
Experimental Tests ◽  
Image Correlation ◽  
Material Surface ◽  
Model Parameters ◽  
Mixed Hardening ◽  
Steel Sheets ◽  
Strain Paths

A hybrid experimental-numerical methodology is presented for the identification of the model parameters regarding a mixed hardening anisotropic finite plasticity fully coupled with isotropic ductile damage in which the micro-crack closure effect is given account for, for steel sheets made of DP1000. The experimental tests involve tensile tests with smooth and pre-notched specimens and shear tests with specimen morphologies recently proposed by D.R. Shouler, J.M. Allwood (Design and use of a novel sample design for formability testing in pure shear, Journal of Materials Processing Technology, Volume 210, Issue 10, 1 July 2010, Pages 1304-1313). These tests cover stress triaxiality ratios lying between 0 (pure shear) and 1/√3 (plane strain). To neutralize machine stiffness effects displacements of the chosen material surface pixels are kept track of using the digital image correlation system ARAMIS, where recorded inputs are synchronized with force measurements. On the numerical part, developed constitutive model is implemented as user defined material subroutine, VUMAT, for ABAQUS/Explicit. FE models for the test cases are built using 3D brick elements (rather than thin shells) and devising developed VUMAT for the constitutive model, model parameters are identified using an inverse parameter identification procedure where the objective function relies on the difference of experimentally observed-numerically predicted forces for the selected pixel displacements. The validity of the material model and transferability of its parameters are tested using tests involving complex strain paths.

Research on strain softening constitutive model of coal-rock combined body with damage threshold

2021 ◽  
pp. 105678952110190
Author(s):  
Tuo Wang ◽  
Zhanguo Ma
Keyword(s):  
Constitutive Model ◽  
Failure Modes ◽  
Strain Softening ◽  
Strain Curve ◽  
Model Parameters ◽  
Test Results ◽  
Underground Engineering ◽  
Rock Stratum ◽  
Damage Constitutive Model ◽  
Coal Rock

The coal seam and the roof of the roadway bear loads together in the underground engineering of coal mine. Especially for the roadway driven along the roof, its deformation is completely different from that arranged in the complete rock stratum. Accurately knowing the mechanical mechanism of coal-rock combined body can help understand the deformation and failure modes of such roadways. This article started with tests of coal-rock combined samples with different height ratios, based on the test results, a strain softening damage constitutive model of coal-rock combined body and a method for solving the parameters of the model were proposed, and the influence of the model parameters was discussed. The test results show that the stress peak value and residual strength of the coal-rock combined samples are negatively correlated with the proportion of coal in the coal-rock combined samples, and have a positive correlation with the confining pressure. The damage constitutive model fitted the test curve well. The model can accurately describe the stress-strain curve of coal-rock combined samples, and can reflect the influence of different height ratios of coal and rock samples and confining pressures. The effects of model parameters were discussed based on the damage constitutive model, which are expected to be widely used in underground engineering.

scholarly journals Finite element modelling of the Taylor impact test in 3D with the Coupled Eulerian-Lagrangian method

2021 ◽  
Author(s):  
François Ducobu ◽  
Anthonin Demarbaix ◽  
Olivier Pantalé
Keyword(s):  
Constitutive Model ◽  
Impact Test ◽  
Reference Model ◽  
Constitutive Models ◽  
Experimental Tests ◽  
Model Parameters ◽  
Cutting Operation ◽  
Taylor Impact ◽  
Taylor Impact Test ◽  
Future Work

When modelling a cutting operation, the constitutive model of the machined material is one of the key parameters to obtain accurate and realistic results. Up to now, the Johnson-Cook model is still the most used, even if an increasing number of models, such as the Hyperbolic TANgent (TANH) model, were introduced last years to overcome its limitations and come closer to the actual material behaviour. Experimental tests on dedicated equipment are usually required to identify the parameters of the constitutive models. This paper introduces the Coupled Eulerian-Lagrangian (CEL) formalism to model in 3D the Taylor impact test, one of the common tests to perform that parameters identification. Indeed, one identification way involves modelling the test to determine the constitutive model parameters by comparing the experimental and the numerical samples geometries. The developed CEL model is validated against a Lagrangian reference model for a steel alloy and the Johnson-Cook constitutive model. The main goal of using the CEL method is to get rid of the elements distortion due to the high strains and strain rates during the test. Mesh dependence of the results is highlighted and a recommendation is provided on the mesh to adopt for future work. The CEL model of the 3D Taylor impact test is then extended to the use of the TANH model. The results are finally compared with that of the Johnson-Cook constitutive model.

An Alternative Technique to Evaluate Crack Propagation Path in Hyperelastic Materials

2012 ◽  
Vol 40 (1) ◽  
pp. 42-58 ◽  
Author(s):  
R. R. M. Ozelo ◽  
P. Sollero ◽  
A. L. A. Costa
Keyword(s):  
Constitutive Model ◽  
Crack Propagation ◽  
Experimental Tests ◽  
Growth Direction ◽  
Propagation Path ◽  
J Integral ◽  
Alternative Technique ◽  
Crack Propagation Path ◽  
Hyperelastic Materials ◽  
Material Constitutive Model

Abstract REFERENCE: R. R. M. Ozelo, P. Sollero, and A. L. A. Costa, “An Alternative Technique to Evaluate Crack Propagation Path in Hyperelastic Materials,” Tire Science and Technology, TSTCA, Vol. 40, No. 1, January–March 2012, pp. 42–58. ABSTRACT: The analysis of crack propagation in tires aims to provide safety and reliable life prediction. Tire materials are usually nonlinear and present a hyperelastic behavior. Therefore, the use of nonlinear fracture mechanics theory and a hyperelastic material constitutive model are necessary. The material constitutive model used in this work is the Mooney–Rivlin. There are many techniques available to evaluate the crack propagation path in linear elastic materials and estimate the growth direction. However, most of these techniques are not applicable to hyperelastic materials. This paper presents an alternative technique for modeling crack propagation in hyperelastic materials, based in the J-Integral, to evaluate the crack path. The J-Integral is an energy-based parameter and is applicable to nonlinear materials. The technique was applied using abaqus software and compared to experimental tests.

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