scholarly journals Research on the Failure and Fracture Evolution of Mylonite with a Prefabricated Circular Opening by Discrete Element Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Kunmeng Li ◽  
Yuanhui Li ◽  
Shuai Xu ◽  
Zhipeng Xiong ◽  
Long An
Keyword(s):  
Numerical Simulation ◽  
Shear Failure ◽  
Biaxial Loading ◽  
Shear Fracture ◽  
Side Wall ◽  
Fracture Pattern ◽  
Circular Opening ◽  
Fracture Evolution ◽  
Loading Tests ◽  
Average Size

In this paper, the failure and fracture process of mylonite with a prefabricated circular opening under biaxial loading is studied by PFC2D code. Firstly, the hoop stress change law of opening wall in the process of loading is theoretically analyzed and three fracture patterns of rocks are proposed. Secondly, the biaxial loading tests of mylonite for numerical simulation are carried out, and the failure and fracture are analyzed from three aspects of space-time evolution of microcracks, energy conversion process, and final damage patterns. As the load progresses, the microcracks start to initiate at the side wall of the opening and the growth velocity of microcracks develops from the slow to fast and then slows down again. The final damage pattern of mylonite with a prefabricated circular opening belongs to shear fracture. The fracture zones start with the side wall spalling and then gradually extend to the border of the rock, which widen from the opening boundary to the border of the rock and slightly twist in the middle. The final fault zone width is about 6 times wider than the average size of simulation particles. Finally, based on the uniaxial compressive strength of mylonite in the laboratory, it is inferred that the fracture pattern of mylonite with a prefabricated circular opening by theoretical analysis is indeed shear failure, which is consistent with the result of numerical simulation.

Study on the Containment Performance of MOX Fuel Processing Glovebox in Earthquake -Loading and Leakage Tests for Window Panels-

2010 ◽  
Vol 5 (4) ◽  
pp. 463-468
Author(s):  
Akihiro Matsuda ◽  
◽  
Yuichi Uchiyama ◽  
Masakatsu Inagaki ◽  
Susumu Tsuchino ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Biaxial Loading ◽  
Acrylic Resin ◽  
Deformation Analysis ◽  
Fuel Processing ◽  
Rubber Seal ◽  
User Subroutine ◽  
Mox Fuel ◽  
Hyperelastic Model ◽  
Loading Tests

This paper shows the results of the leakage tests and the large deformation analysis of a full-scale glovebox window to establish the capacity of the containment of the MOX fuel manufacturing glovebox during an earthquake. In leakage tests, the stainless steel container installed on the reverse of the glovebox window was pressurized with a halogen-air mixture after deformation was applied to the upper part of window frame using 6 micro handy jacks, and to the four glove-ports using electrical actuators. A numerical model for the rubber seal was obtained with biaxial loading tests of chloroprene sheet specimens. Tensile loading tests of acrylic resin specimens were conducted to measure the material modulus. The FEM code ABAQUS was applied to the numerical simulation and the user-subroutine function for the hyperelastic model was used to predict the deformation of the rubber seal. These tests demonstrated that a glovebox window constructed with a rubber seal and a resin panel shows no leakage larger than 0.1 vol%/h with large static deformation. The results of the numerical simulation showed that the rubber seal resolved the effects of deformation of a window panel on the containment barrier, and that two lips of the rubber seal play a key role on the containment of the glovebox.

scholarly journals Prefabricated Urban Underground Utility Tunnels: A Case Study on Mechanical Behaviour with Strain Monitoring and Numerical Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yonggang Xiao ◽  
Jubing Zhang ◽  
Jie Cao ◽  
Changhong Li
Keyword(s):  
Numerical Simulation ◽  
Working Conditions ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Low Cost ◽  
Side Wall ◽  
Operating Conditions ◽  
Land Occupation ◽  
Depth Analysis ◽  
Simulation Results

The prefabricated urban utility tunnels (UUTs) have many advantages such as short construction period, low cost, high quality, and small land occupation. However, there is still a lack of in-depth analysis of the mechanical performance of the prefabricated urban utility tunnel (UUT) structure with bolted connections under different working conditions. In this paper, the force performance of a prefabricated UUT in Tongzhou District, Beijing, was studied under different working conditions using two methods: field monitoring and numerical simulation. The multichannel strain monitor was used for monitoring, and the internal wall concrete and bolt strain change data under the two conditions of installation and backfill were obtained. Combined with the construction process of the UUTs, a three-dimensional numerical model was established by COMSOL, where the build-in bolt assembly was used to simulate the longitudinal connection of the tunnel. The simulation results were compared with the measured data to verify the rationality of the computational model. The simulation results showed that the concrete and bolts on the inner wall of the tunnel work well under the two conditions of installation and backfilling; The deformation of the top plate of the prefabricated tunnel was approximately parabolic, with the largest vertical displacement (0.37 mm) in the middle and the most sensitive to the vertical load in the central part of the roof. The central portion of the side wall had the largest displacement (0.17 mm) in the inner concave. The tensile stress of bolt 3 increased the most (30.75 MPa) but was still much smaller than the yield strength of the bolt. The concrete and bolts of the UUT were found to work well through force analysis under operating conditions. In conclusion, analysis of structural forces and deformation failure modes will help design engineers understand the basic mechanisms and select the appropriate UUT structure.

Effect of Slag Layer on Flow Patterns in a Gas Stirred Ladle

2006 ◽  
Vol 510-511 ◽  
pp. 490-493 ◽  
Author(s):  
Sung-Ho Cho ◽  
Sung Hwan Hong ◽  
Jeong Whan Han ◽  
Byung Don You
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Model Experiment ◽  
Central Area ◽  
Side Wall ◽  
Slag Layer ◽  
Flow Patterns ◽  
Water Model ◽  
Slag Viscosity ◽  
Mixing Behavior

Flow patterns and mixing behaviors in a gas stirred steelmaking ladle with a slag layer were discussed using a water model experiment as well as a numerical simulation. While the water model experiment was performed to investigate the effect of slag on the mixing behavior in ladle, the numerical simulation was carried out to figure out the flow pattern in ladle with a slag layer. Slag viscosity and its thickness in ladle were considered as major variables. It was found that a slag layer made a great change in the flow pattern in ladle, which, in turn, affected on the mixing behavior in ladle. A flow pattern without a slag layer showed that rising bubbles eventually made a recirculation loop at the central area of the ladle and this flow pattern was regarded as a favorable flow pattern for the better mixing behavior. However, a flow pattern with a slag layer showed distorted and localized recirculating loop near side wall below slag layer. This eventually gave a longer mixing time in ladle with a slag layer. Moreover, as the gas flow rate increases, slag existing on top of the ladle was found to be entrained into the melt. Slag viscosity and its thickness were found to be major variables affecting the behavior of slag entrainment. Lower the slag viscosity and thicker the slag layer, much more slag on top of the melt was entrained into the melt.

The Studies on Numerical Simulation of Unidirectional Solidification Process in 23t Steel Ingot

2012 ◽  
Vol 502 ◽  
pp. 46-50
Author(s):  
Guang Wu Ao ◽  
Ming Gang Shen ◽  
Zhen Shan Zhang ◽  
Li Li Hong
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Temperature Distribution ◽  
Steel Ingot ◽  
Side Wall ◽  
Solidification Process ◽  
Unidirectional Solidification ◽  
Finite Element Software ◽  
Solidification Processes

In this paper, by using the commercial finite-element software of ProCAST, unidirectional solidification processes in 23t steel ingot were simulated. Emphasis is placed on analysis of required time for complete solidification of steel ingot and temperature distribution about ingot and side wall during the solidification process. By comparing simulation values and measured values of side wall during the solidification process, the simulated results conclusively demonstrate that our developed model is feasible and valuable.

scholarly journals Numerical Simulation Virtual Test of Torsion Shear for Asphalt Mixture

2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Jun Xie ◽  
Yougang Yang
Keyword(s):  
Numerical Simulation ◽  
Shear Failure ◽  
Failure Process ◽  
Asphalt Mixture ◽  
Test Method ◽  
Reconstruction Method ◽  
Virtual Test ◽  
Torsional Shear ◽  
Shear Process ◽  
Air Void

In order to analyze the torsional shear process of asphalt mixtures in a microscopic view, the numerical simulation of a torsional shear test of an asphalt mixture was carried out by discrete element method. Based on the defects of existing algorithms, the method of random reconstruction of the existing 3D model of the asphalt mixture was improved, and a new reconstruction method was proposed. A 3D numerical model of the asphalt mixture contained irregular-shaped coarse aggregate, mineral gradation, and asphalt mortar; furthermore, the particle algorithm established the air void distribution. Then, the numerical simulation of the asphalt mixture’s torsional shear was completed; in addition, the stress, displacement, and contact of the specimens at each stage were analyzed. The results showed that the stress and displacement in different stages changed greatly with the loading, i.e., the crack generated from a weak point on the surface and then spread to the ends with an oblique angle of about 45°. At the same time, the shear failure process of the asphalt mixture was studied. The virtual test method could accomplish the implementation of the numerical simulation of torsional shear; it also provided a good research method for analysis of the asphalt mixture’s shear failure process.

The Impact Analysis of Ground Stability Caused by Exploiting Underground Coal

2011 ◽  
Vol 243-249 ◽  
pp. 3147-3150
Author(s):  
Shu Xian Liu ◽  
Xiao Gang Wei ◽  
Shu Hui Liu ◽  
Li Ping Lv
Keyword(s):  
Numerical Simulation ◽  
Coal Mining ◽  
Impact Analysis ◽  
Shear Failure ◽  
Failure Process ◽  
Wall Rock ◽  
Strong Impact ◽  
Element Analysis ◽  
Deformation And Failure ◽  
The Impact

Disaster caused by exploiting underground coal is due to original mechanical equilibrium of underground rock has been destroyed when underground coal is exploited. And Stress redistribution and stress concentration of wall rock in the goaf happened too. As many complex factors exist such as complex structures of ground, multivariate stope boundary conditions, many stochastic mining factors and so on, it is difficult to evaluate the damage of the geological environment caused the excavation by surrounding underground coal accurately. Besides that, the coexistence of continuous and discontinuous of deformation and failure of wall rock make a strong impact on the ground, and the co-exist of tension, compression and shear failure also pay a great deal contribution to the destroy. Due to the mechanical property and deformation mechanism of goaf are complex , changeable, nonlinear and probabilistic, which changes with in space and time dynamically, it can not be studied analytically by the classical mathematical model and the theory of mechanics computation. Through finite element analysis software ABAQUS, a numerical simulation of the process of underground coal mining have been made. After make a research of the simulation process, it shows the change process of stress environment of wall rock and deformation and failure process of rock mass during the process of coal mining. The numerical simulation of the process can provide theoretical basis and technical support to the protection and reinforcement of laneway the process of coal excavation. Besides that, it also provides a scientific basis and has a great significance to reasonable Excavation and control of mind-out area.

scholarly journals Numerical simulation of natural convection in an inclined porous cavity under time-periodic boundary conditions with a partially active thermal side wall

RSC Advances ◽  
2017 ◽  
Vol 7 (28) ◽  
pp. 17519-17530 ◽  
Author(s):  
Feng Wu ◽  
Gang Wang
Keyword(s):  
Numerical Simulation ◽  
Natural Convection ◽  
Boundary Conditions ◽  
Periodic Boundary ◽  
Side Wall ◽  
Periodic Boundary Conditions ◽  
Porous Cavity ◽  
Thermal Boundary Conditions ◽  
The Right ◽  
Time Periodic

Natural convection in an inclined porous cavity with positively or negatively inclined angles is studied numerically for time-periodic boundary conditions on the left side wall and partially active thermal boundary conditions on the right wall.

scholarly journals NUMERICAL SIMULATION OF CYCLIC LOADING TESTS OF COMBINED COLUMNS WITH FRICTION DAMPING MECHANIZM

2014 ◽  
Vol 70 (4) ◽  
pp. I_101-I_108
Author(s):  
Hisakazu SAKAI ◽  
Sumio SAWADA ◽  
Yoshikazu TAKAHASHI ◽  
Akira IGARASHI ◽  
Kazumasa MANABE ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Cyclic Loading ◽  
Friction Damping ◽  
Loading Tests ◽  
Cyclic Loading Tests

Numerical Simulation of Polyurethane Pad Punching Process

2014 ◽  
Vol 941-944 ◽  
pp. 1817-1821
Author(s):  
Xiao Xiong Wang ◽  
Jing Liu ◽  
Jing Tao Han ◽  
Qian Liu
Keyword(s):  
Numerical Simulation ◽  
Cross Section ◽  
Shear Failure ◽  
Sheet Thickness ◽  
Control Parameters ◽  
Arbitrary Lagrangian Eulerian ◽  
Adaptive Meshing ◽  
Finite Element Program ◽  
Element Program ◽  
Punching Process

A numerical simulation was conducted to investigate the effect of the punching clearance, the thickness of sheet, and the hardness of polyurethane pad on the process of punching by finite element program ABAQUS which based on shear failure criterion and arbitrary Lagrangian-Eulerian adaptive meshing method. And the collapse height dimension and width dimension tendency of the sheet under different control parameters was analyzed after punching process according to this simulation result. The results show that the collapse height dimension and width dimension decreased with the increase of the polyurethane hardness, it means the cross section quality perspicuously has been increased; the collapse height dimension and width dimension decreased with the increasing of the sheet thickness; while the influence of the punching gap is indistinctive.

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