Study on Mechanical Characteristic of Two-Layer Steel Plate Concrete Shaft Lining under Non Uniform Pressure

2013 ◽  
Vol 351-352 ◽  
pp. 17-21
Author(s):  
Hai Bing Cai ◽  
Hua Cheng ◽  
Yi Chun Huang
Keyword(s):  
Mechanical Characteristic ◽  
Steel Plate ◽  
Concrete Strength ◽  
Simulation Method ◽  
Structure Design ◽  
Actual Condition ◽  
Uniform Pressure ◽  
Research Findings ◽  
Shaft Lining ◽  
Layer Steel

Aiming at the actual condition that non uniform pressure act on shaft linging, adopting finite element numerical simulation method, mechanical characteristic of two-layer steel plate concrete shaft lining is researched. Based on pertinent regulations of concrete strength improving coefficient in the state of triaxiality stress, designed twolayer steel plate concrete shaft lining meet strength need under non uniform pressure. The research findings can provide referrence for similar structure design.

scholarly journals Hydraulic structure design and downhole flow field optimization of geophysical drill bits in a limestone stratum

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093125
Author(s):  
Jing Zhu ◽  
Zhiqiang Huang ◽  
Yachao Ma ◽  
Dou Xie ◽  
Xueying Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Hydraulic Structure ◽  
Field Tests ◽  
Simulation Method ◽  
Flow Path ◽  
Structure Design ◽  
Drill Bit ◽  
Drilling Performance ◽  
Flow Field Characteristics ◽  
Shaft Lining

The hydraulic structure of conventional geophysical drill bit is designed for the general stratum. When conventional geophysical drill bit pierces into a limestone stratum, the shape of cuttings is large because of the high brittleness of limestone. The cuttings are ground repeatedly; this phenomenon can reduce drilling efficiency and increase drilling costs. According to the characteristics of limestone cuttings, the numerical simulation method is used to research downhole flow field characteristics of conventional geophysical drill bit. First, the influence of key hydraulic structure parameters on cuttings removal performance is found. Then, the hydraulic structure is optimized. The flow field characteristics of the hydraulic structure of the geophysical drill bit before and after optimization in the flow path is analyzed, at the bottom of the bit and the annulus area of the shaft lining. The optimized downhole crossflow area increased from 50% to 98%. No vortex was observed at the exit of the flow path and cuttings groove. The downhole pressure gradient increased from 0.12 Mpa to 0.15 Mpa. The cutting removal space in the annulus area of the shaft lining is fully utilized. Field tests show that the cutting removal and drilling performance of optimized geophysical drill bit has improved and the drilling speed increases by 20.6%.

Combination of Support Vector Machine and K-Fold cross-validation for prediction of long-term degradation of the compressive strength of marine concrete

2018 ◽  
Vol 1 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Chunxiang Qian ◽  
Wence Kang ◽  
Hao Ling ◽  
Hua Dong ◽  
Chengyao Liang ◽  
...  
Keyword(s):  
Support Vector Machine ◽  
Environmental Factors ◽  
Cross Validation ◽  
Concrete Strength ◽  
Simulation Method ◽  
Support Vector ◽  
Svm Model ◽  
Artificial Neural Network Ann ◽  
Influence Degree ◽  
Fold Cross Validation

Support Vector Machine (SVM) model optimized by K-Fold cross-validation was built to predict and evaluate the degradation of concrete strength in a complicated marine environment. Meanwhile, several mathematical models, such as Artificial Neural Network (ANN) and Decision Tree (DT), were also built and compared with SVM to determine which one could make the most accurate predictions. The material factors and environmental factors that influence the results were considered. The materials factors mainly involved the original concrete strength, the amount of cement replaced by fly ash and slag. The environmental factors consisted of the concentration of Mg2+, SO42-, Cl-, temperature and exposing time. It was concluded from the prediction results that the optimized SVM model appeared to perform better than other models in predicting the concrete strength. Based on SVM model, a simulation method of variables limitation was used to determine the sensitivity of various factors and the influence degree of these factors on the degradation of concrete strength.

Stability Prediction of Surrounding Rocks and Optimum Design of Roof-Bolt Parameters in Deep Roadway

2013 ◽  
Vol 353-356 ◽  
pp. 436-439
Author(s):  
De Sen Kong ◽  
Yong Po Chen
Keyword(s):  
Prediction Method ◽  
Simulation Method ◽  
Complex Stress ◽  
Roof Bolt ◽  
Deformation And Failure ◽  
Long Run ◽  
Research Findings ◽  
Stress Environment ◽  
Classification Prediction ◽  
The Stability

In order to forecast the stability of deep roadway and optimize the parameters of bolts, the complex stress environment and the multivariate surrounding rocks characteristics of deep roadway were analyzed. Then the classification prediction method and the numerical simulation method were simultaneously used to analysis the stability of surrounding rocks. Furthermore, the supporting parameters of bolts were also designed optimally. It was shown that the characteristics of stress distribution, deformation and failure zone of surrounding rocks are not ideal. So it is necessary to optimize the supporting parameters of deep roadway. All these research findings will provide the theory basis for bolts of deep roadway and will ensure the optimization of bolts and the stability of deep roadway in the long run.

Numerical Simulation of Ultrasonic Shear Wave Propagation Based on the Finite Element Method

2014 ◽  
Vol 488-489 ◽  
pp. 926-929 ◽  
Author(s):  
Jian Ma ◽  
Yang Zhao ◽  
Ji Hua Sun ◽  
Shuai Liu
Keyword(s):  
Numerical Simulation ◽  
Shear Wave ◽  
Present Method ◽  
Steel Plate ◽  
Mode Conversion ◽  
Simulation Method ◽  
The Finite Element Method ◽  
Propagation Process ◽  
The Time Domain ◽  
Ultrasonic Shear

The present paper provided a kind of numerical simulation method which was employed to guide the process of ultrasonic nondestructive testing and analyze the inspection results. The simulation concerning the propagation process of shear wave in the steel plate was carried out using the ANSYS, according to the mechanism of ultrasonic mode conversion. Then, the frequency, velocity and refraction angle were extracted from the time-domain date in order to verify the simulation. It is found that the result of simulation agrees well with the theoretical one, which shows that the present method is correct and reliable.

Analysis and Design Recommendations for the Collapse of a Concrete Silo

2011 ◽  
Vol 250-253 ◽  
pp. 2877-2880 ◽  
Author(s):  
Guang Lin Yuan ◽  
Lu Dan Tian
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Structure Design ◽  
Test Results ◽  
Reinforcing Bars ◽  
Design Recommendations ◽  
Analysis And Design ◽  
The Future ◽  
Design And Construction

Accidents of the cement manufacturers’ reinforced concrete silo structures frequently occurred currently in China, because of quality problems, causing enormous losses. The collapse status of a cement raw meal silo is investigated. Combined with the test results of the location and spacing of silo wall’s reinforcing bars, concrete strength, cracks and defects, the reasons for collapse of silo wall are analyzed and design recommendations for concrete silo structures are made. This can give reference to reinforced concrete silo structure design and construction in the future.

scholarly journals Structure parameter optimization and bearing limit analysis of the expansion unit of three-roller tube expander

2020 ◽  
Vol 7 (5) ◽  
pp. 191630
Author(s):  
Gang Bi ◽  
Zhan Qu ◽  
Zhenquan Wang ◽  
Liangbin Dou ◽  
Mengmeng Li
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Gauge Length ◽  
Structure Design ◽  
Design Parameters ◽  
Roller Tube ◽  
Unit Structure ◽  
Drilling Technology ◽  
Expansion Force ◽  
Proper Length

The critical technical issues for the structure design of three-roller tube expander were first studied and analysed in this paper. Then, the major design parameters of the expansion unit structure and the bearing limit of 12¼″ three-roller tube expander were optimized and investigated by finite-element numerical simulation method. Results from study show that the required expansion force increases when the taper angle of the roller outer surface gets larger, taking the axial expansion force as the quantitative indicators. It is suggested that the roller tape angle of the expansion unit should be in the range of 9–12° considering the proper length of the roller and the non-self-locking tube expansion process. The required expansion force of the bellows first decreases and then increases when the gauge length of the expansion unit becomes longer. The optimal value of the gauge length is 50 mm considering the proper length of the roller. And according to the numerical simulation results, the designed three-roller tube expander meets the strength requirements. The results of this study are of great significance to the expend bellows drilling technology.

Influence Analysis of Different Prestress Stretching Order to Rectangle Aqueduct

2011 ◽  
Vol 255-260 ◽  
pp. 1138-1141
Author(s):  
Ze Yu Wu ◽  
Xin Li Bai ◽  
Yu He Li
Keyword(s):  
Steel Plate ◽  
Local Stress ◽  
Simulation Method ◽  
Water Transfer ◽  
Construction Period ◽  
Finite Element Software ◽  
Order Variation ◽  
Calculation Results ◽  
North Water ◽  
Stretching Process

Large finite element software is used to analyze Shuangji River rectangle aqueduct in the South-to-North Water Transfer Project. The stress and displacement of the whole structure are obtained under different stretching order of prestress during the aqueduct construction period. Calculation results show that, from the point of stress, the better prestress stretching order is stretching longitudinal first, then the transverse and finally vertical; from the point of displacement, drawing order variation has little influence on displacements in the stretching process; it is a relatively good simulation method to add a steel plate to the area where the prestressed strands are acted on. In this way, the real anchor state can be simulated, and the local stress concentration can be reduced.

Extraction Shafting Oscillation Characteristic of Hydro Turbine Generating Sets Based on Prony Algorithm

2014 ◽  
Vol 889-890 ◽  
pp. 563-568
Author(s):  
Zhe Wu ◽  
Yun Zeng ◽  
Yan Yan Zeng ◽  
Shi Ge Yu
Keyword(s):  
Optimization Design ◽  
Attenuation Factor ◽  
Vibration Signal ◽  
Simulation Method ◽  
Structure Design ◽  
Operating Conditions ◽  
Transient Model ◽  
Hydro Turbine ◽  
Generating Sets ◽  
Prony Algorithm

Hydro turbine generating sets vibration is an important factor affecting the safe operation of hydropower stations. The research on the vibration characteristics is basic for the unit structure design, control design and hydropower station powerhouse structure optimization design. Based on built transient model of the hydropower turbine generating sets shafting, this paper constructed the whole hydropower turbine generating sets operating system by combine the hydro turbine, the generator object model, the governor and the excitation controller. Using numerical simulation method to obtained the shafting vibration data under different operating conditions. And then used Prony algorithm to extract the oscillation characteristics of amplitude, frequency, attenuation factor and phase angle from the vibration signal of hydro turbine generating sets shafting parameters. The simulation results show that the proposed method is effective.

Development and some Prospects of the Shaft Lining Structure

2012 ◽  
Vol 166-169 ◽  
pp. 636-639
Author(s):  
Lin Lin Wu ◽  
Yong Guang Lian ◽  
Yong Xiang Kong ◽  
Yong Jun Ma ◽  
Bin Jiang ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Steel Plate ◽  
High Strength ◽  
Damage Mechanism ◽  
Strength Concrete ◽  
Advantages And Disadvantages ◽  
Composite Shaft ◽  
Lining Structure ◽  
Shaft Lining

The damage mechanism and causes of the shaft lining structures are introduced, and the advantages and disadvantages of some current shaft lining structures are analyzed. The prospects of steel plate-high strength concrete composite shaft lining structure are proposed in this paper.

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