scholarly journals Investigation on the Nonlinear Strength Properties and Damage Statistical Constitutive Model for Frozen Sandy Soils

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
De Zhang ◽  
Enlong Liu ◽  
Xingyan Liu ◽  
Ge Zhang ◽  
Xiao Yin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Sandy Soils ◽  
Continuum Damage Mechanics ◽  
Strength Properties ◽  
Principal Stresses ◽  
Confining Pressures ◽  
Damage Constitutive Model ◽  
Frozen Sandy Soil

There are many flaws, such as fissures, cavities, and inclusions, in geomaterials, which make their mechanical properties with great randomness and uncertainty. Upon loading, the soil structure gradually losses the bearing capacity due to the transformation from microdefects to macroscopic breakage bands. Based upon the experimental data of frozen sandy soils, a new nonlinear strength equation between the first and third principal stresses was proposed, and then the nonlinear strength properties for frozen sandy soils in σ-τ plane were analyzed. In addition, by assuming that the microstrength of frozen sandy soil obeys the Weibull distribution function, a statistical damage constitutive model was established based upon the framework of continuum damage mechanics (CDM), with few parameters and a high accuracy. Compared with experimental data, the new model can well grasp the nonlinear strength properties and simulate the stress-strain relationships under different confining pressures for frozen sandy soils.

A Physically Based Damage Constitutive Model for Stress Relaxation

2014 ◽  
Author(s):  
Yu Zhou ◽  
Xuedong Chen ◽  
Zhichao Fan ◽  
Yichun Han
Keyword(s):  
Stress Relaxation ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Model Comparison ◽  
Continuum Damage Mechanics ◽  
Reheat Cracking ◽  
Physically Based ◽  
Damage Constitutive Model ◽  
Evolution Behavior ◽  
The Continuum

A damage constitutive model for stress relaxation was proposed based on the continuum damage mechanics theory, in terms of the characteristics of damage induced by stress relaxation which is associated with reheat cracking. The effects of strain hardening and the precipitation and growth of carbides on the stress evolution behavior were considered in the present model. To validate the accuracy of the constitutive model, comparison of the predicted result provided by the model and the experimental data of stress relaxation for 2.25Cr-1Mo-0.25V ferritic steel was made. It is shown that the damage constitutive model can be used to predict the stress relaxation behavior and reheat cracking further for low alloy ferritic steels.

Constitutive Description for Drawing Limit of Magnesium Alloy Tube Based on Continuum Damage Mechanics

2009 ◽  
Vol 610-613 ◽  
pp. 951-954 ◽  
Author(s):  
Ying Tong ◽  
Guo Zheng Quan ◽  
Bin Chen
Keyword(s):  
Magnesium Alloy ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Plastic Behavior ◽  
Continuum Damage ◽  
Rigid Plastic ◽  
Alloy Tube ◽  
Limit Graph ◽  
Damage Constitutive Model

The elasto-plastic behavior and the drawing limit of a kind of magnesium alloy tube were investigated based on the foundational theories of the larger deformation of material and continuum damage constitutive model. The corresponding finite element numerical algorithm was developed based on the constitutive model. The non-mandrel drawing limit graph according to the diameter at different tube thickness of an AZ31B tube with diameter 10mm at 250°C and drawing velocity 100mm/s was achieved, and safe & unsafe area got partitioned. The maximum damage value was evaluated to be 0.324 according to height reduction ratio limit and rigid-plastic FE analysis.

A Developed Damage Constitutive Model for Circular Steel Tubes of Reticulated Shells

2020 ◽  
Vol 20 (09) ◽  
pp. 2050106
Author(s):  
Sheng He ◽  
Haosen Wang ◽  
Stéphane P. A. Bordas ◽  
Peng Yu
Keyword(s):  
Constitutive Model ◽  
Damage Mechanics ◽  
Dynamic Instability ◽  
Damage Model ◽  
Nonlinear Dynamic Analysis ◽  
Continuum Damage Mechanics ◽  
Steel Tubes ◽  
Mapping Algorithm ◽  
Comparison Results ◽  
Damage Constitutive Model

The aim of this paper is that the precise description of damage behavior is crucial to well catch the mechanical behavior of structures in the dynamic numerical simulation, and address the issue on the coupled plastic-damage constitutive model for circular steel tubes of reticulated shells under severe earthquake. Continuum Damage Mechanics (CDM) constitutive model established by Lemaitre is reviewed at the beginning. Then, an improved damage model for circular steel tubes of reticulated shells is developed based on Lemaitre’s model by replacing the original damage evolution law with a new one suitable for circular steel tubes. In addition, we introduce the stress update process. In this procedure, the well-known operator split strategy, which leads to the standard elastic predictor/return mapping algorithm, is adopted to solve the evolution problem of the improved model. Exploiting user-defined material subroutine, the implementation of the model is achieved within software ANSYS using BEAM189 element. Finally, the dynamic response of reticulated shells under severe earthquake are numerically simulated with the proposed model and with the conventional Prandtl-Reuss model, respectively. The comparison results show that the consideration of material damage accumulation, on the one hand, may change the failure mode of reticulated shells from dynamic instability to strength failure; on the other, may reduce the dynamic ultimate load obviously. This consideration should be taken into account when conducting nonlinear dynamic analysis of reticulated shells.

scholarly journals Constitutive Model for Concrete: An Overview

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 782-788 ◽  
Author(s):  
Mehdi Shekarbeigi ◽  
Hasan Sharafi
Keyword(s):  
Constitutive Model ◽  
Damage Mechanics ◽  
Constitutive Models ◽  
Continuum Damage Mechanics ◽  
Constitutive Modelling ◽  
Continuum Damage ◽  
Endochronic Theory ◽  
Small Deformations

In the last three decades, the constitutive modelling of concrete evolved considerably. This paper describes various developments in this field based on different approaches such anelasticity, plasticity, continuum damage mechanics, plastic fracturing, endochronic theory, microplane models, etc. In this article the material is assumed to undergo small deformations. Only time independent constitutive models and the issues related to their implementation are discussed

scholarly journals A Nonlinear Statistical Damage Constitutive Model for Porous Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yue Pan ◽  
Zhiming Zhao ◽  
Liu He ◽  
Guang Wu
Keyword(s):  
Constitutive Model ◽  
Solid Skeleton ◽  
Porous Rocks ◽  
Different Types ◽  
Confining Pressures ◽  
Damage Constitutive Model ◽  
Statistical Damage Constitutive Model ◽  
Energy Theory ◽  
Water Contents ◽  
Statistical Damage

In the current paper, the deformation behaviours of rocks during compression are studied by testing 10 groups of sandstone samples with different porosity characteristics. According to the energy theory, the rock material was divided into two parts: solid skeleton and voids. A statistical damage-based approach was adopted to establish a nonlinear statistical damage constitutive model. The validity of the statistical damage constitutive model is verified by the test data. The statistical damage constitutive model performs well in each stage of rock compression before failure. For different types of rocks, different confining pressures, and different water contents, the statistical damage constitutive model fits well. This model can be applied to most types of rocks and in most engineering environments.

Development and Finite Element Implementation of Stress-Dependent Elastoviscoplastic Constitutive Model with Damage for Asphalt

2003 ◽  
Vol 1832 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Andrew C. Collop ◽  
A. (Tom) Scarpas ◽  
Cor Kasbergen ◽  
Arian de Bondt
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Compressive Strain ◽  
Local Strain ◽  
Continuum Damage Mechanics ◽  
Dependent Case ◽  
Strain Compatibility ◽  
Incremental Formulation ◽  
Stress Dependent

The development and finite element (FE) implementation of a stress-dependent elastoviscoplastic constitutive model with damage for asphalt is described. The model includes elastic, delayed elastic, and viscoplastic components. The strains (and strain rates) for each component are additive, whereas they share the same stress (i.e., a series model). This formulation was used so that a stress-based nonlinearity and sensitivity to confinement could be introduced into the viscoplastic component without affecting the behavior of the elastic and delayed elastic components. A simple continuum damage mechanics formulation is introduced into the viscoplastic component to account for the effects of cumulative damage on the viscoplastic response of the material. The model is implemented in an incremental formulation into the CAPA-3D FE program developed at Delft University of Technology in the Netherlands. A local strain compatibility condition is utilized such that the incremental stresses are determined explicitly from the incremental strains at each integration point. The model is demonstrated by investigating the response of a semirigid industrial pavement structure subjected to container loading. Results show that the permanent vertical strains in the non-stress-dependent case are significantly lower than the permanent vertical strains in the stress-dependent case. Results also show that in the stress-dependent case, there is a more localized area of high permanent vertical compressive strain directly under the load at approximately halfdepth in the asphalt compared with the non-stress-dependent case, in which the distribution is more even.

Damage Extension Forces and Piezoelectric Fracture Criteria

2004 ◽  
Vol 20 (4) ◽  
pp. 277-283 ◽  
Author(s):  
X. H. Yang ◽  
L. Dong ◽  
C. Y. Chen ◽  
C. Wang ◽  
Y. T. Hu
Keyword(s):  
Damage Mechanics ◽  
Piezoelectric Materials ◽  
Continuum Damage Mechanics ◽  
The Finite Element Method ◽  
Fracture Criteria ◽  
Nonlinear Fracture ◽  
Crack Tips ◽  
Damage Constitutive Model ◽  
Nonlinear Criterion ◽  
External Loads

AbstractDue to external loads, damage extension forces will drive mechanical and electrical damages to evolve in piezoelectric materials from the viewpoint of continuum damage mechanics, so it is important for understanding piezoelectric fracture mechanism and estimating the utilizing life and safety of a piezoelectric device to study the damage extension forces. Based on the static piezoelectric damage constitutive model established in our previously published papers, general expressions of the damage extension forces are given. The finite element method and the iterative procedure are utilized to calculate the extension forces at crack-tips in the samples for the experiments of Park and Sun's, and then the linear and nonlinear fracture criteria are presented. It is revealed from the list of the normalized mean square deviations that the nonlinear criterion is better.

Development of “Material Specific” Creep Continuum Damage Mechanics-Based Constitutive Equations

2020 ◽  
Author(s):  
Ricardo Vega ◽  
Jaime A. Cano ◽  
Calvin M. Stewart
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Creep Strain ◽  
Creep Deformation ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Constitutive Models ◽  
Continuum Damage Mechanics ◽  
Creep Strain Rate ◽  
Continuum Damage

Abstract The objective of this study is to introduce a method for creating “material specific” creep continuum damage mechanics-based constitutive models. Herein, material specific is defined as a constitutive model based on the mechanism-informed minimum creep strain rate (MCSR) equations found in deformation mechanism maps and calibrated to available material data. The material specific models are created by finding the best MCSR model for a dataset. Once the best MCSR model is found, the Monkman Grant inverse relationship between the MCSR and rupture time is employed to derive a rupture equation. The equations are substituted into continuum damage mechanics-based creep strain rate and damage evolution equations to furnish predictions of creep deformation and damage. Material specific modeling allows for the derivation of creep constitutive models that can better the material behavior specific to the available data of a material. The material specific framework is also advantageous since it has a systematic framework that moves from finding the best MCSR model, to rupture time, to damage evolution and, creep strain rate. Data for Alloy P91 was evaluated and a material specific constitutive model derived. The material specific model was able to accurately predict the MCSR, creep deformation, damage, and rupture of alloy P91.

scholarly journals Statistical Damage Constitutive Model for Cemented Sand considering the Residual Strength and Initial Compaction Phase

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Cai Tan ◽  
Ming-dao Yuan ◽  
Yong-sheng Shi ◽  
Bing-sheng Zhou ◽  
Hao Li
Keyword(s):  
Constitutive Model ◽  
Residual Strength ◽  
Damage Mechanics ◽  
Triaxial Compression ◽  
Triaxial Stress ◽  
Cemented Sand ◽  
Damage Constitutive Model ◽  
Statistical Damage Constitutive Model ◽  
Initial Compaction ◽  
Statistical Damage

Based on continuum damage mechanics and the assumption of volume invariance, a damage constitutive model of cemented sand under triaxial stress was established while considering residual strength. Statistical theory was then introduced into this model. Assuming that the microunit strength of cemented sand obeys a Weibull random distribution, an expression of microunit strength based on the Mohr–Coulomb criterion was derived. Additionally, a damage evolution equation and a statistical damage constitutive model of cemented sand under triaxial stress were established. In order to consider the nonlinear deformation and volume change in the initial pore compaction stage, the critical point reflecting the completion of the initial compaction stage was determined. This was done by applying the volume invariance assumption to the linear portion of the stress and strain curve and performing a coordinate transformation. The nonlinearity of the initial compaction stage was fitted by a quadratic function. A triaxial compression test of cemented sand was then carried out to verify this proposed method. The results show that the calculated values by the damage constitutive model fit well with the actual experimental values and that the calculated results can reflect the stress softening, residual strength, and initial compaction characteristics of cemented sand, which shows the rationality and feasibility of the model.

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