Grinding Damage Prediction for Ceramics via CDM Model

1999 ◽  
Vol 122 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Bi Zhang ◽  
Xianghe Peng
Keyword(s):  
Damage Mechanics ◽  
Coupling Effect ◽  
Three Dimensional ◽  
Continuum Damage Mechanics ◽  
Inelastic Behavior ◽  
Finite Element Program ◽  
Damage Prediction ◽  
Grinding Conditions ◽  
Element Program ◽  
Three Dimensional Finite Element

A continuum damage mechanics (CDM) model is proposed to predict grinding damage of ceramics. The model takes into account the inelastic behavior of ceramics, the effect of grinding induced hydrostatic pressure and the coupling effect between volumetric and deviatoric deformations on damage. A numerical algorithm is proposed and a three-dimensional finite element program is developed for the model. Damage is analyzed for silicon nitride ceramics subjected to single grit grinding conditions. The damage predicted by the model shows good agreement to the measurement results obtained by experiments. The model can also be used to predict grinding damage for other types of materials. [S1087-1357(00)70301-7]

Comparative Analysis of Several Construction Scheme of a Large-Sized Tie-Arch Aqueduct

2011 ◽  
Vol 94-96 ◽  
pp. 2350-2354
Author(s):  
Shu Zhong Lei ◽  
Zhong Xin Wang ◽  
Jian Ting Xu ◽  
Chi Peng Liu
Keyword(s):  
Comparative Analysis ◽  
Prestressed Concrete ◽  
Three Dimensional ◽  
Stability Control ◽  
River Diversion ◽  
Finite Element Program ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Stress And Deformation ◽  
Three Dimensional Finite Element

An aqueduct of larger-span prestressed concrete arch structure for river diversion project is located in coastal areas, and raises difficult questions on deformation and stability control of the construction process due to greater wind load and poor soil. Due to the limited width of bracket erection, this paper put forward five possible construction schemes, and does the comparative analysis using three-dimensional finite element program, and gets the economic and reasonable one. Finally conduct a pressure test after the bracket erection, and verify the analysis results using measured stress and deformation data.

Effect of Cavities from Gypsum Dissolution on Bearing Capacity of Soil under Square Footing

2020 ◽  
Vol 857 ◽  
pp. 221-227
Author(s):  
Israa Saleh Hussein ◽  
Lamyaa Najah Snodi
Keyword(s):  
Bearing Capacity ◽  
Water Flow ◽  
Three Dimensional ◽  
Cavity Volume ◽  
Finite Element Program ◽  
Square Footing ◽  
Gypsum Content ◽  
Element Program ◽  
Three Dimensional Finite Element ◽  
Gypseous Soil

This study deals with cavities under square footing which resulted from gypsum dissolving due to water flow in gypseous soil. This process leads to collapse of soil structure and progressive compression. A model was developed for governing the mass-transport to assess the variation of gypsum content of the soil during dissolution by ground water flow then cavity formation was adopted. A general three-dimensional finite element program (PLAXIS 3D) was selected for numerical analysis method to generate the solution. The study included a number of variables and their effect on bearing capacity of gypseous soil such as (gypsum content, cavity volume and location). The cavity was represented as axis and plane cavity which has square section. The results show that the most dangerous case is found when the cavity locates at the center of footing base (Z/B = 0), where the bearing capacity decreased by (14, 37, and 69%) for (20, 30, and 40%) gypsum dissolving ratio respectively. Also, the bearing capacity decreased when the cavity volume increases due to increasing dissolution ratio. The effect of cavity became disappear after (Z/B = 4). While, when using plane cavity, there was no cavity at center of footing base (Z/B = 0) because it considered as a hole not cavity. When using plane cavity, the bearing capacity decreased by (28, 43, and 53%) for (20, 30, and 40%) dissolving ratio respectively when (Z/B=1). The effect of cavity on the bearing capacity would be disappear as the distance from footing center increase until it became disappear at (Z/B = 6 m). The plane cavity is more dangerous than axis cavity.

FE Modeling of FRP-Concrete Interface for very High Cycle Fatigue Behavior

2013 ◽  
Vol 577-578 ◽  
pp. 165-168 ◽  
Author(s):  
M. Mahal ◽  
T. Blanksvärd ◽  
B. Täljsten
Keyword(s):  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Finite Element Program ◽  
Element Program ◽  
Three Dimensional Finite Element ◽  
Concrete Interface

The fatigue damage of FRP-concrete interface is a major problem in strengthened structures subjected to fatigue loading. The available FRP-concrete interface models published in the literature usually deal with fracture mechanism approach, which is unsuitable for high cycle fatigue damage. In this study, a constitutive micro model is developed for FRP-concrete interface for high cycle fatigue and incorporated into a three dimensional finite-element program. Numerical analysis of a double lap joint is carried out, and the results show that the proposed model is reasonably accurate.

Analysis on Avoid Incision in Underground Engineering Reinforcement Technique against Cutting Resistance

2013 ◽  
Vol 853 ◽  
pp. 596-599
Author(s):  
Bo Wang ◽  
Yong Zhang ◽  
Hong Wei Liu
Keyword(s):  
Three Dimensional ◽  
Penetration Resistance ◽  
Surrounding Rock ◽  
Underground Engineering ◽  
Finite Element Program ◽  
Cutting Resistance ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Three Dimensional Finite Element ◽  
Poor Stability

In view of serious degree of mouth formation rock weathering, poor stability, the construction excavation characteristics such as easy to collapse of underground engineering, incision reinforcement technology is used in underground engineering in the mouth period of construction, which changes the mechanical properties of surrounding rock and improves the penetration resistance of surrounding rock. Using three dimensional finite element program (ls-dyna) numerical simulations show that the stratified structure of the grouting tube in the surrounding rock is similar with covering layer thickness steel ball, which makes the projectile yaw in the process of penetration movement. As is shown through comprehensive calculation and analysis, the zero incision reinforcement technology can make the penetration resistance of the underground engineering mouth period increased by 30% ~ 40%.

Hydroelasticity Vibration of a Rectangular Tank Wall

2005 ◽  
Author(s):  
K. S. Kim ◽  
D. W. Kim ◽  
Y. B. Lee ◽  
S. H. Choi ◽  
Y. S. Kim
Keyword(s):  
Fluid Velocity ◽  
Three Dimensional ◽  
Tank Wall ◽  
Finite Element Program ◽  
Assumed Mode Method ◽  
Rectangular Tank ◽  
Mode Method ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Three Dimensional Finite Element

A theoretical study is carried out on the hydroelasticity vibration of a rectangular tank wall. It is assumed that the tank wall is clamped along the plate edges. The fluid velocity potential is used for the simulation of fluid domain and to obtain the added mass due to wall vibration. In addition, the vibration characteristics of stiffened wall of the rectangular tank are investigated. Assumed mode method is utilized to the stiffened plate model and hydrodynamic force is obtained by the proposed approach. The coupled natural frequencies are obtained from the relationship between kinetic energies of a wall including fluid and the potential energy of the wall. The proposed analytical approach was found to be in good agreement with the results of a well-known commercial three-dimensional finite element program.

Estimation of Bearing Capacity Dropping Due to Cavities from Gypseous Soils Melting

2020 ◽  
Vol 857 ◽  
pp. 409-416
Author(s):  
Ahmed Al-Obaidi ◽  
Reem S. Najim
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Horizontal Distance ◽  
Finite Element Program ◽  
Significant Movement ◽  
Gypsum Content ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Permeable Soil ◽  
Three Dimensional Finite Element

The presence of gypsum in the soil will cause problems if the source of freshwater is available and permeable soil permitting significant movement of water is to take place. The solubility of gypsum by excess water from irrigation or localized leak into the gypseous soil may cause cavity formation. In this research, a model was developed for governing the mass-transport to assess the variation of gypsum content of the soil during dissolution. A general three-dimensional finite element program (PLAXIS tunnel) was selected for the numerical analysis method to generate the solution. Parameters that affect the bearing capacity of a square footing represented by the gypsum content, the cavity volume, and the location of the cavity which represent by three offset distances from the footing center to the cavity center (x, y, and z), where (X) represents the horizontal distance, (Y) represents the vertical (depth) distance, and (Z) represents the diagonal distance. The main results show that the cavity location found to be the most parameter that affects the bearing capacity ratio (BCR). The minimum values are found when the cavity locates at the center of the footing base, and the lowest one (0.211) when the gypsum dissolved equal to 40%, also there is no effect of the cavity location when the ratio of (X/B) and (Z/B) exceed (3.0) for any depth and when the gypsum dissolved less than 10%. For high gypsum dissolution (more than 30%), the dimensionless ratios (X/B), (Z/B), and (Y/B) of the cavity must be more than 5.0.

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