scholarly journals A Study of Coupled Creep Damaged Constitutive Model of Artificial Frozen Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Dongwei Li ◽  
Junhao Chen ◽  
Yan Zhou
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Yield Criterion ◽  
Creep Damage ◽  
Confining Pressure ◽  
Frozen Soil ◽  
Finite Element Program ◽  
Finite Element Software ◽  
Frozen Clay

Artificial frozen soil is a kind of typical creep material, and the frozen clay under the unloading stress paths of high-confining pressure conforms to the improved the Zienkiewicz–Pande parabola-type yield criterion, and the Mohr–Coulomb yield function can describe the shear yield surface of artificial frozen clay under low-confining pressure. Based on the results of triaxial creep and shear tests for artificial frozen soil, the viscoplastic damage variable and evolution rule of artificial frozen clay were obtained by using the theory of viscoelastic-plastic mechanics and damage mechanics. An improved Zienkiewicz–Pande parabola-type yield criterion was used instead of a linear Newton body to obtain a coupled constitutive model of viscoelastic-plastic damage in the frozen soil under the unloading stress paths and to derive the coupling flexibility matrix for viscoelastic and viscoplastic damage. A finite element program of artificial frozen soil considering creep damage was written in the Visual Fortran 6.6A environment and embedded into the nonlinear finite element software ADINA as a user subroutine. The results of numerical simulation and laboratory testing were identical, with a maximum error of no more than 4.8%. This work shows that it is reasonable to describe the creep constitutive model of frozen soil with the viscoelastic-plastic-coupled constitutive model.

Study on Elastic-Plastic Damage Constitutive Model of Frozen Soil Based on Energy Dissipation Theory

2013 ◽  
Vol 423-426 ◽  
pp. 1187-1192 ◽  
Author(s):  
Zhi Min Li ◽  
Tao Liu ◽  
Zhi Li Cui
Keyword(s):  
Energy Dissipation ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Yield Criterion ◽  
Dissipation Function ◽  
Frozen Soil ◽  
Elastic Plastic ◽  
Plastic Damage ◽  
Plastic Dissipation ◽  
Damage Constitutive Model

Starting from the thermodynamics, model of frozen soil is studied by energy dissipation theory and the inside and outside the state variables is given under isothermal conditions. Damage of frozen soil is re-flecked by effective stress and damage tensor in Damage Mechanics. Dissipation function is in form of plastic dissipation function (DP yield criterion) and the damage dissipation function. And plastic dissipation function is coupled of the damage variable. Through the elastic-plastic and damage evolution, frozen soil incremental elastic-plastic damage constitutive model is made. And finite element scheme is given.

The Review of Computational FE Software for Creep Damage Mechanics

2012 ◽  
Vol 510 ◽  
pp. 495-499 ◽  
Author(s):  
De Zheng Liu ◽  
Qiang Xu ◽  
Zhong Yu Lu ◽  
Dong Lai Xu
Keyword(s):  
Finite Element ◽  
Damage Mechanics ◽  
Creep Damage ◽  
Damage Analysis ◽  
Finite Element Software ◽  
Current State ◽  
Computational Capability

This paper reports a review on the computational (finite element) software for creep damage analysis. Firstly, it summarizes the current state of how to obtain such computational capability then it concludes with a preference of in-house software. It further reviews the validation practice. Finally, it completes with an outlines of the approach to be used in the developing in-house FE software.

scholarly journals Low-Cycle Fatigue Crack Initiation Simulation and Life Prediction of Powder Superalloy Considering Inclusion-Matrix Interface Debonding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4018
Author(s):  
Shuming Zhang ◽  
Yuanming Xu ◽  
Hao Fu ◽  
Yaowei Wen ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Interface Debonding ◽  
Damage Evolution Equation ◽  
Finite Element Software

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

Progressive failure analysis of scarf-repaired composite laminate based on damage constitutive model

2016 ◽  
Vol 233 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Qiuyi Shen ◽  
Zhenghao Zhu ◽  
Yi Liu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Laminate ◽  
Damage Mechanics ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Three Dimensional ◽  
Zone Model ◽  
State Variables ◽  
Element Analysis

A three-dimensional finite element model for scarf-repaired composite laminate was established on continuum damage model to predict the load capacity under tensile loading. The mixed-mode cohesive zone model was adopted to the debonding behavior analysis of adhesive. Damage condition and failure of laminates and adhesive were subsequently addressed. A three-dimensional bilinear constitutive model was developed for composite materials based on damage mechanics and applied to damage evolution and loading capacity analyses by quantifying damage level through damage state variables. The numerical analyses were implemented with ABAQUS finite element analysis by coding the constitutive model into material subroutine VUMAT. Good agreement between the numerical and experimental results shows the accuracy and adaptability of the model.

Finite Element Simulation of the Creep Behavior of 2.25Cr-1Mo-0.25V Steel Based on Continuum Damage Mechanics

2015 ◽  
Vol 750 ◽  
pp. 266-271 ◽  
Author(s):  
Yu Zhou ◽  
Xue Dong Chen ◽  
Zhi Chao Fan ◽  
Yi Chun Han
Keyword(s):  
Genetic Algorithm ◽  
Finite Element ◽  
Creep Behavior ◽  
Constitutive Equations ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Creep Damage ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Element Simulation

The creep behavior of 2.25Cr-1Mo-0.25V ferritic steel was investigated using a set of physically-based creep damage constitutive equations. The material constants were determined according to the creep experimental data, using an efficient genetic algorithm. The user-defined subroutine for creep damage evolution was developed based on the commercial finite element software ANSYS and its user programmable features (UPFs), and the numerical simulation of the stress distribution and the damage evolution of the semi V-type notched specimen during creep were studied. The results showed that the genetic algorithm is a very efficient optimization approach for the parameter identification of the creep damage constitutive equations, and finite element simulation based on continuum damage mechanics can be used to analyze and predict the creep damage evolution under multi-axial stress states.

Investigation of the Constitutive Modle of Saturated Frozen Soil Based on Damage

2013 ◽  
Vol 353-356 ◽  
pp. 221-224
Author(s):  
Shuang Zhang ◽  
Chun An Tang ◽  
Lei Li ◽  
Shuai Li
Keyword(s):  
Phase Transition ◽  
Temperature Field ◽  
Stress Field ◽  
Constitutive Model ◽  
Internal Structure ◽  
Damage Mechanics ◽  
Frozen Soil ◽  
Unfrozen Water ◽  
Freezing And Thawing ◽  
Water Field

Saturated frozen soil is composed of soil, unfrozen water and ice, whose subgrade deformation is due to the weakened of internal structure which coursed by damage of the materials in the process of the cycle of freezing and thawing. Considing of the heterogeneity of saturated frozen soil and the phase transition between water and ice, and using of the damage mechanics theory, thermodynamics theory, filtration mechanics theory, a constitutive model of saturated frozen soil is setted up, which is of the coupfing problem of temperature field, water field and stress field. The rationality and validity of the model is verified by the experiment. It is also provided a new method for the study of frozen soil.

Finite Element Simulation of Freezing Technology for Borehole Stability of Gas Drilling

2014 ◽  
Vol 962-965 ◽  
pp. 415-418
Author(s):  
Zong Gang Wang ◽  
Zhen Wei
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Freezing Point ◽  
Drill String ◽  
Frozen Soil ◽  
Conductive Heat ◽  
Formation Water ◽  
Borehole Stability ◽  
Finite Element Program ◽  
Gas Drilling

The gas drilling mainly relies on the high speed air flow to carry the cuttings. The formation water or oil mixed with the cuttings and then they stick together in clumps after the formation water or oil went into the hole annulus, the clumps stick on the drill string and the borehole. The clumps may block the hole annulus and cause the stick or bury the drill string and many other complex accident. It could stop the cuttings from sticking with the liquid through freezing the formation fluid with the liquid nitrogen. And the natural geotechnical becomes into the frozen soil, and forms the temporary solid which is intact, high strength and low-permeability. This paper utilize the ANSYS finite element program to simulate the 3D model of borehole and hole wall to calculate the freezing radius of the steady state, heat loss, temperature of the freezing point and the conductive heat time of the unsteady state. And this study has provided the basis of the freezing technology for borehole stability of gas drilling.

Behavior of Lead-Free Solder Under Thermomechanical Loading

2004 ◽  
Vol 126 (3) ◽  
pp. 367-373 ◽  
Author(s):  
Y. Wei ◽  
C. L. Chow ◽  
K. J. Lau ◽  
P. Vianco ◽  
H. E. Fang
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Base Alloy ◽  
Back Stress ◽  
General Purpose ◽  
Lead Free ◽  
Element Analysis ◽  
Different Temperatures ◽  
Free Solder

This paper presents an investigation of lead-free Sn-Ag base alloy, 95.5Sn-3.9Ag-0.6Cu, both experimentally and analytically. Experimentally, the deformation behavior of the material was measured for different temperatures (25°C and 1000°C) over a range of strain rates (10−5 to 10−3/s) under isothermal and thermomechanical conditions. Development of a unified viscoplastic constitutive model followed, taking into account the effects of the measured strain rate and temperature changes. The temperature rate effects are considered in the evolution equation of back stress. In order to include material degradation in the solder, the theory of damage mechanics is applied by introducing two damage variables in the viscoplastic constitutive model. Finally, the constitutive model is coded into a general-purpose finite element computer program (ABAQUS) through its user-defined material subroutine (UMAT). The damage-coupled finite element analysis (FEA) is then employed to monitor the condition of failure of a notched component. The predicted and measured maximum loads have been compared and found to be satisfactory. In addition, the calculated damage distribution contours enable the identification of potential failure site for failure analysis.

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.

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