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

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.

Effect of Hydrogen on Creep Behavior of a Vanadium-Modified CRMO Steel and its Continuum Damage Analysis

2018 ◽  
Author(s):  
Yu Zhou ◽  
Xuedong Chen ◽  
Zhichao Fan ◽  
Peng Xu ◽  
Xiaoliang Liu
Keyword(s):  
Constitutive Model ◽  
Creep Strain ◽  
Creep Behavior ◽  
Hydrogen Pressure ◽  
Damage Mechanics ◽  
Elevated Temperatures ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Methane Pressure ◽  
Crmo Steel

Creep properties both in hot hydrogen and in air of a vanadium-modified CrMo steel 2.25Cr1Mo0.25V, widely used in hydroprocessing reactors in petrochemical industry, were investigated to determine the effect of hydrogen on high-temperature creep behavior of the low-alloy ferritic steel. The minimum creep strain rate in hydrogen is higher than that in air, whereas the creep strain at failure in hydrogen is relatively smaller. Many tiny spherical cavities are dispersively distributed in the ruptured specimen under hydrogen, which has relatively higher Vickers hardness. Based on the thermodynamics theory, the pressure of methane generated by the so-called “methane reaction” in the vanadium-modified CrMo steel can be calculated by using corresponding thermodynamic data, assuming that methane can reach its equilibrium state during cavitation. Meanwhile, a creep constitutive model based on continuum damage mechanics (CDM) was proposed, taking methane pressure into consideration. The results show that methane pressure increases nonlinearly with increase of hydrogen pressure while it decreases gradually with increase of temperature. The constitutive model considering the damage induced by methane pressure can be used to predict the effect of hydrogen pressure and temperature on creep life, indicating that the influence of hydrogen at elevated temperatures becomes smaller when increasing temperature or decreasing hydrogen pressure.

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.

Stress Relaxation Continuum Damage Constitutive Equations for Relaxation Performance Prediction

2012 ◽  
Vol 455-456 ◽  
pp. 1434-1437
Author(s):  
Jin Quan Guo ◽  
Wei Zhang ◽  
Xiao Hong Sun
Keyword(s):  
Stress Relaxation ◽  
Constitutive Equations ◽  
Damage Mechanics ◽  
Constitutive Models ◽  
Continuum Damage Mechanics ◽  
Creep Model ◽  
Continuum Damage ◽  
Relaxation Equation ◽  
Creep Tests ◽  
Analysis Technique

Stress relaxation constitutive equations based on Continuum Damage Mechanics, Kachanov-Robatnov creep model, and stress relaxation equation has been developed by analyzing stress relaxation damage mechanisms and considering the relationship that stress relaxation is creep at various stresses. And, the constitutive differential equations were integrated to predict stress relaxation performance by using numerical analysis technique. In order to validate the approach, the predicted results are compared to the experimental results of uni-axial isothermal stress relaxation tests conducted on 1Cr10NiMoW2VNbN steel with the same temperature of creep tests. Good agreement between results of relaxation tests and the predicted results indicates that the developed constitutive models can be used in the relaxation behavior evaluation of high temperature materials.

Endochronic Theory of Continuum Damage Mechanics

1998 ◽  
Vol 124 (2) ◽  
pp. 200-208 ◽  
Author(s):  
Han C. Wu ◽  
C. Komarakulnanakorn
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Endochronic Theory

Fatigue Life of the Human Teeth: A Continuum Damage Approach

2019 ◽  
Vol 43 ◽  
pp. 1-19
Author(s):  
Theddeus Tochukwu Akano
Keyword(s):  
Fatigue Life ◽  
Damage Mechanics ◽  
Stress Amplitude ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Elastoplastic Model ◽  
Human Teeth ◽  
Proposed Model ◽  
Number Of Cycles ◽  
Cycles To Failure

Normal oral food ingestion processes such as mastication would not have been possible without the teeth. The human teeth are subjected to many cyclic loadings per day. This, in turn, exerts forces on the teeth just like an engineering material undergoing the same cyclic loading. Over a period, there will be the creation of microcracks on the teeth that might not be visible ab initio. The constant formation of these microcracks weakens the teeth structure and foundation that result in its fracture. Therefore, the need to predict the fatigue life for human teeth is essential. In this paper, a continuum damage mechanics (CDM) based model is employed to evaluate the fatigue life of the human teeth. The material characteristic of the teeth is captured within the framework of the elastoplastic model. By applying the damage evolution equivalence, a mathematical formula is developed that describes the fatigue life in terms of the stress amplitude. Existing experimental data served as a guide as to the completeness of the proposed model. Results as a function of age and tubule orientation are presented. The outcomes produced by the current study have substantial agreement with the experimental results when plotted on the same axes. There is a notable difference in the number of cycles to failure as the tubule orientation increases. It is also revealed that the developed model could forecast for any tubule orientation and be adopted for both young and old teeth.

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