Analysis of moisture damage susceptibility of semi-rigid base materials based on hydrodynamic pressure erosion test and damage constitutive model

2020 ◽  
Author(s):  
Dong Sha ◽  
Baofeng Pan ◽  
Yiren Sun ◽  
Tiankai Che ◽  
Jiale Lu
Keyword(s):  
Damage Mechanics ◽  
Damage Model ◽  
Hydrodynamic Pressure ◽  
Damage Mechanism ◽  
Moisture Damage ◽  
Rigid Base ◽  
Wheel Load ◽  
Damage Models ◽  
Base Materials ◽  
Erosion Test

The hydrodynamic erosion generated by the pumping action of the wheel load during rain and snow is the main cause of the semi-rigid base failure. Unfortunately, however, very few experimental methods and damage models can reasonably describe and predict the moisture damage performance of semi-rigid base materials under the pumping action. To address this issue, a hydrodynamic pressure erosion test was conducted firstly. Then, the compressive test was performed on the eroded specimens to evaluate the damage mechanism of semi-rigid base materials subjected to hydrodynamic erosion. Finally, a moisture-induced damage model that is applicable to the semi-rigid base materials was established by the concept of damage mechanics. The results indicated that the presented damage model encapsulates the complex behavior of the semi-rigid base materials under the hydrodynamic pressure and provides a more rational method for predicting the moisture damage performance of semi-rigid base materials.

Comparison of Two Damage Models for Prediction of Failure in Stress Corrosion Cracking

2018 ◽  
Author(s):  
Sorabh Singhal ◽  
Yogeshwar Jasra ◽  
Ravindra K. Saxena
Keyword(s):  
Crack Initiation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Driving Force ◽  
Damage Mechanics ◽  
Damage Model ◽  
Corrosion Cracking ◽  
Force Model ◽  
Initiation Time ◽  
Damage Models

In the present work, Stress corrosion cracking (SCC) and its mechanical behavior are presented. SCC represents complex behavior due to electrochemical and mechanical interaction. Damage models are proposed to predict crack initiation time for stainless steel under constant load using the concept of continuum damage mechanics to show incremental damage accumulation which finally leads to failure of the material. Two damage models applicable to prediction of damage in SCC, Lemaitre damage model and damage driving force model proposed by Kamaya are compared. The comparative study of the results obtained by these damage models shows that in Lemaitre damage law cracks initiate randomly while in damage driving force model the stress concentration occurs around the periphery of damaged element results in increased damage force. The study can be used to estimate the crack initiation time in SCC under corrosive atmosphere.

A Damage Model for Adhesively Bonded Single-Lap Thick Composite Joints

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Sayed A. Nassar ◽  
Jianghui Mao ◽  
Xianjie Yang ◽  
Douglas Templeton
Keyword(s):  
Damage Mechanics ◽  
Resin Composite ◽  
Analytical Data ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Epoxy Adhesive ◽  
Failure Behavior ◽  
Adhesively Bonded ◽  
Damage Initiation ◽  
Damage Models

A proposed damage model is used for investigating the deformation and interfacial failure behavior of an adhesively bonded single-lap thick joint made of S2 glass/SC-15 epoxy resin composite material. The bonding material is 3M Scotch-Weld Epoxy Adhesive DP405 Black. Continuum damage mechanics models are used to describe the damage initiation and final failure at or near the interface. The effect of adhesive overlap length, thickness, and plasticity on the interfacial shear and normal stresses is studied. Experimental and analytical data are used to validate the proposed damage models.

Study on Damage Evolution Mechanism of Concrete under Uniaxial Tension

2012 ◽  
Vol 238 ◽  
pp. 46-50
Author(s):  
Wei Feng Bai ◽  
Ying Cui ◽  
Qian Wang ◽  
Jun Feng Guan ◽  
Jian Wei Zhang
Keyword(s):  
Uniaxial Tension ◽  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Characteristics ◽  
Deformation And Failure ◽  
Damage And Failure ◽  
Basic Parameters ◽  
Fundamental Research

The damage and failure mechanism of quasi-brittle materials is the most fundamental research topic in Damage Mechanics. In this paper, the mesoscopic damage mechanism of concrete under uniaxial tension was discussed. The rupture and yield damage modes in meso-scale were introduced as the two basic parameters to define the damage accumulated variable. The results show that the proposed statistical damage model can accurately predict the whole deformation and failure process of concrete under uniaxial tension, including the two-stage deformation characteristics and the size effect.

scholarly journals Quantitative Damage and Fracture Mode of Sandstone under Uniaxial Load Based on Acoustic Emission

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ying Xu ◽  
Qiangqiang Zheng ◽  
Xin Gao ◽  
Rongzhou Yang ◽  
Xian Ni ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Mechanism ◽  
Damage Mechanics ◽  
Shear Failure ◽  
Rock Fracture ◽  
Damage Model ◽  
Damage Models ◽  
Uniaxial Load ◽  
Damage And Fracture ◽  
Ae Signals

The damage degree and fracture mechanism of the rock are important to the bearing performance of the rock mass and the stability of the overlying structure. Most of the existing damage models for characterizing rock damage exclude the range of postpeak stress or do not consider the compaction and closure stage of the fracture, and the description of the quantitative damage of sandstone is not accurate enough. In addition, the description of the rock fracture mechanism under load is not exact enough. Aiming at the problem of quantitative damage and fracture mechanism of the loaded rock, this paper adopts acoustic emission (AE) to monitor the loading process of sandstone under uniaxial loading. In accordance with the characteristics of the AE signal, the loading stage of sandstone under uniaxial load is divided into three stages: initial hit stage, hit stability stage, and hit instability stage. By modifying the traditional damage model and combining the AE signals of the sandstone under the load, a modified damage mechanics model is obtained, which can fully express the entire loading stage. Furthermore, through the analysis of AE signals, the fracture mechanism of sandstone under uniaxial load is studied. The results show that the modified damage model can quantitatively describe the damage at different loading stages which include two areas including the fracture compaction closure stage and the postpeak stress stage. The failure and instability of sandstone under uniaxial load is mainly shear failure. The research results can provide a reference for the nondestructive testing of sandstone and engineering reliability in geotechnical engineering.

A Coupled Elastic-Plastic Damage Model for Rock Material

2014 ◽  
Vol 488-489 ◽  
pp. 799-802
Author(s):  
Hong Jie Chen ◽  
Wei Ya Xu ◽  
Ru Bin Wang ◽  
Wei Wang
Keyword(s):  
Damage Mechanics ◽  
Damage Model ◽  
Confining Pressure ◽  
Damage Mechanism ◽  
Coupling Model ◽  
Internal Variable ◽  
Elastic Plastic ◽  
Softening Behavior ◽  
Plastic Damage ◽  
Damage Constitutive Model

With complex mechanics character and under the action of compression and tension in tri-direction, rock will show coupled plastic-damage mechanism as its basic character. Phenomenological coupled elastic-plastic-damage constitutive model with internal variable is proposed based on thermal mechanics theory, elastic law and macro damage mechanics. Numerical experiments on this model and analyze the model character. The result shows that the coupling model could realize rocks softening behavior brought about by damage and strength enlargement caused by confining pressure increasing.

Continuum Damage Mechanics Studies on the Dynamic Fracture of Concrete

1985 ◽  
Vol 64 ◽  
Author(s):  
E. P. Chen
Keyword(s):  
Dynamic Fracture ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Damage Mechanism ◽  
Continuum Damage ◽  
Strain Rate Effects ◽  
Perfectly Plastic ◽  
Material Stiffness ◽  
Elastic Perfectly Plastic

ABSTRACTThe dynamic fracture of concrete in tension is studied by applying a continuum damage model developed by the author and his coworkers [1–3]. In this model, the degree of damage in concrete corresponds to the fraction of concrete volume that has been tension relieved, and tensile microcracking has been taken as the damage mechanism. In compression, the concrete is assumed to respond in an elastic/perfectly plastic manner. Strain-rate effects have been explicitly included in the model. Accumulation of damage in the material is reflected by the progressive weakening of the material stiffness. Examples involving center- and edge-cracked plate specimens subjected to the action of step and ramp loads are used to demonstrate the material responses predicted by the model. The bulk pressure versus strain relationships at locations close to the crack tip clearly show strainsoftening behavior. The damage tends to localize around the crack and its extent in the specimen is dependent upon both the crack geometry and the loading type. These results are presented and their implications are discussed.

Studying the effect of a hydrostatic stress/strain reduction factor on damage mechanics of concrete materials

2013 ◽  
Vol 22 (5-6) ◽  
pp. 149-159
Author(s):  
Ziad N. Taqieddin ◽  
George Z. Voyiadjis
Keyword(s):  
Damage Mechanics ◽  
Internal State ◽  
Hydrostatic Stress ◽  
Damage Model ◽  
Reduction Factor ◽  
State Variables ◽  
Elastic Plastic ◽  
Damage Models ◽  
Plastic Damage ◽  
Concrete Materials

AbstractIn the non-linear finite element analysis (NFEA) of concrete materials, continuum damage mechanics (CDM) provides a powerful framework for the derivation of constitutive models capable of describing the mechanical behavior of such materials. The internal state variables of CDM can be introduced to the elastic analysis of concrete to form elastic-damage models (no inelastic strains), or to the elastic-plastic analysis in order to form coupled/uncoupled elastic-plastic-damage models. Experimental evidence that is well documented in literature shows that the susceptibility of concrete to damage and failure is distinguished under deviatoric loading from that corresponding to hydrostatic loading. A reduction factor is usually introduced into a CDM model to reduce the susceptibility of concrete to hydrostatic stresses/strains. In this work, the effect of a hydrostatic stress/strain reduction factor on the performances of two NFEA concrete models will be studied. These two (independently published) models did not provide any results showing such effect. One of these two models is an elastic-damage model, whereas the other is an uncoupled elastic-plastic-damage model. Simulations and comparisons are carried out between the performances of the two models under uniaxial tensile and compressive loading conditions. Simulations are also provided for the uncoupled elastic-plastic-damage model under the following additional loading conditions: biaxial tension and biaxial compression, uniaxial cyclic loading, and varying ratios of triaxial compressive loadings. These simulations clearly show the effect of the reduction factor on the numerically depicted behaviors of concrete materials. To have rational comparisons, the hydrostatic stress reduction factor applied to each model is chosen to be a function of the internal state variables common to both models. Therefore, once the two models are calibrated to simulate the experimental behaviors, their corresponding reduction factors are readily available at every increment of the iterative NFEA procedures.

Geometry Transferability of Lemaitre's Continuum Damage Mechanics Model in the Plane Stress Specimens

2013 ◽  
Vol 592-593 ◽  
pp. 266-270 ◽  
Author(s):  
Nima Allahverdizadeh ◽  
Andrea Manes ◽  
Marco Giglio ◽  
Andrea Gilioli
Keyword(s):  
Plane Stress ◽  
Damage Mechanics ◽  
Numerical Models ◽  
Damage Model ◽  
High Strength ◽  
Experimental Tests ◽  
Continuum Damage Mechanics ◽  
Failure Behavior ◽  
Continuum Damage ◽  
Damage Models

Different damage mechanics models have been proposed by researchers to calibrate the failure behavior of materials. Continuum damage mechanics (CDM) models are one of the main categories of damage models that can be exploited in numerical simulations. In this paper Lemaitres damage model, has been applied to finite element models of flat specimens. These models allow assessing the geometry transferability of the previously calibrated CDM model investigating in different geometry and loading conditions. Four different types of plane stress specimens have been designed to get different stress triaxialities which cover shear dominant and high triaxiality failure. Experimental tests were also done and the obtained data were critically compared with the results from numerical models. The tested material is Ti-6Al-4V titanium alloy which is a widely used material in aerospace industry because of its high strength and low density.

Fracture-Damage Model for Anchored Discontinuous Jointed Rockmass and its Application

2007 ◽  
Vol 353-358 ◽  
pp. 973-976 ◽  
Author(s):  
Gang Wang ◽  
Shu Cai Li ◽  
Shu Gang Wang ◽  
Jing Long Li ◽  
Xiao Jing Li
Keyword(s):  
Constitutive Relation ◽  
Damage Mechanics ◽  
Damage Model ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Equivalent Strain ◽  
Complex Stress ◽  
The State ◽  
Constructive Model ◽  
Fracture Damage

According to the theories of fracture mechanics and damage mechanics, the constructive model and fracture damage mechanism of brittle discontinuous jointed rockmass are systematically studied under the state of complex stress in this paper. By the aid of the method of equivalent strain energy, the constitutive relation of anchored brittle discontinuous jointed rockmass is derived under the state of compression-shearing. The constitutive relation under the state of tension-shearing is also developed according to the theory of self-consistence. Finally, based on the above constructive models, the three-dimensional finite element procedure has been developed to model the ground movements that occur when underground power-houses of pumped-storage power station are installed in discontinuous jointed rockmass. The anchor supporting is an important component of this underground power-houses excavation work. Besides the displacement field and the secondary state of stress induced by the excavation disturbance, the effect of anchoring and the damage evolution around the power-houses have been particularly described during the process of installation. The numerical results obtained by numerical simulation were compared with that of field monitoring in order to verify the validity of the proposed models.

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