Model for predicting displacement-dependent lateral earth pressure

2009 ◽  
Vol 46 (8) ◽  
pp. 969-975 ◽  
Author(s):  
Guoxiong Mei ◽  
Qiming Chen ◽  
Linhui Song
Keyword(s):  
Earth Pressure ◽  
The State ◽  
Passive State ◽  
Test Results ◽  
Lateral Earth Pressure ◽  
The Earth ◽  
Proposed Model ◽  
Pressure Changes ◽  
The Relationship ◽  
Good Agreement

A model for predicting displacement-dependent lateral earth pressure was proposed based on an earth pressure – displacement relationship commonly observed in practice. The proposed model is a monotonically increasing and bounded function, with an inflection point at the displacement of s = 0 at which the earth pressure changes from the intermediate active state (the state between active and at-rest) to the intermediate passive state (the state between at-rest and passive). The proposed model can predict the relationship between earth pressure and retaining structure movement for any condition intermediate to the active and passive states, which was verified by the experimental data reported in published literature. The predicted lateral earth pressure coefficients are in good agreement with the test results of model tests reported in the literature.

The Prediction of Thermal Conductivity of Agricultural Residues from Straw for Biomass Energy

2013 ◽  
Vol 779-780 ◽  
pp. 1419-1422 ◽  
Author(s):  
Lin Lu ◽  
Li Jiang ◽  
Qing Feng ◽  
He Ping Wang
Keyword(s):  
Thermal Conductivity ◽  
Rice Straw ◽  
Agricultural Residues ◽  
Biomass Energy ◽  
Thermal Probe ◽  
Moisture Contents ◽  
Proposed Model ◽  
Wire Method ◽  
The Relationship ◽  
Good Agreement

Agricultural residues from straw are widely used for energy and other applications. The thermal conductivity is one of the most important thermophysical properties considered when using agricultural residues, such as rice straw, in renewable energy engineering. In this paper, the thermal conductivity of rice straw was measured using a thermal probe by the transient hot wire method at selected moisture contents, temperatures and dry densities. The moisture contents of the samples ranged from 0 to 21.47 percent wet basis and the dry densities ranged from 90.7 to 136.4 kg/m3 and the temperature ranged from 0 to 170°C. Under those conditions, the thermal conductivity was measured and analyzed. Experiment results showed that the thermal conductivity increases with the increases of the density, moisture content and temperature, and the relationship among them is approximately described in a linear way. A new model to predict the thermal conductivity of agricultural residues from straw was proposed. The calculated results by the proposed model are in good agreement with the experimental data.

Mathematical Modeling of Ultra-High-Pressure Waterjet Peening

2005 ◽  
Vol 127 (2) ◽  
pp. 186-191 ◽  
Author(s):  
S. Kunaporn ◽  
M. Ramulu ◽  
M. Hashish
Keyword(s):  
Mathematical Modeling ◽  
High Pressure ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Analytical Models ◽  
Test Results ◽  
Ultra High Pressure ◽  
Proposed Model ◽  
Compressive Residual Stresses ◽  
Good Agreement

Waterjet peening is a recent promising method in surface treatment. It has the potential to induce compressive residual stresses that benefit the fatigue life of materials similar to the conventional shot peening process. However, there are no analytical models that incorporate process parameters (i.e., supply pressure, jet exposure time, and nozzle traverse rate, etc) to allow predicting the optimized peening process. Mathematical modeling of high-pressure waterjet peening was developed in this study to describe the relation between the waterjet peening parameters and the resulting material modifications. Results showed the possibility of using the proposed mathematical model to predict an initial range for effective waterjet peening under the variation of waterjet peening conditions. The high cycle fatigue tests were performed to validate the proposed model and fatigue test results showed good agreement with the predictions.

Investigation on arc light intensity in gas metal arc welding. Part 1: Relationship between arc light intensity and arc length

1997 ◽  
Vol 211 (5) ◽  
pp. 345-353 ◽  
Author(s):  
C D Yoo ◽  
Y S Yoo ◽  
H-K Sunwoo
Keyword(s):  
Light Intensity ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Arc Length ◽  
Metal Arc Welding ◽  
Proposed Model ◽  
Welding Part ◽  
The Relationship ◽  
Good Agreement

The arc length has been detected through the arc because the welding current and voltage vary linearly with the arc length. In this work, the relationship between the arc light intensity and arc length is investigated through analytic modelling. The arc light intensity is derived as a function of the arc length and welding current using the heat balance in the plasma. Experiments are carried out to verify the proposed model and to find out the effects of welding conditions on the arc light intensity in gas metal arc welding (GMAW). The arc light intensity varies proportionally to the arc length and signal quality is enhanced with a fast weaving speed. The predicted results of the arc light intensity show reasonably good agreement with the experimental data.

Pull-out capacity of single batter piles in sand

1986 ◽  
Vol 23 (3) ◽  
pp. 387-392 ◽  
Author(s):  
A. M. Hanna ◽  
A. Afram
Keyword(s):  
Design Method ◽  
Soil Mechanics ◽  
Earth Pressure ◽  
Axial Loading ◽  
Test Results ◽  
Passive Earth Pressure ◽  
Sand Soil ◽  
Pull Out ◽  
Batter Piles ◽  
Good Agreement

The pull-out capacity of single rigid vertical and batter piles in sand and subjected to axial loading has been investigated. Good agreement was found when test results on instrumented model piles were compared with theoretical estimates. The effect of pile inclination on the pull-out capacity has been explained by means of variable mobilized passive earth pressure on the pile's perimeter. A design method and charts are presented. Key words: pile foundation, pull-out capacity, vertical pile, batter pile, sand–soil mechanics.

scholarly journals The Brandon mathematical model describing the effect of calcination and reduction parameters on specific surface area of ex-ADU UO₂ powders

2016 ◽  
Vol 6 (3) ◽  
pp. 54-59
Author(s):  
Trong Hung Nguyen ◽  
Ba Thuan Le
Keyword(s):  
Mathematical Model ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Uranyl Carbonate ◽  
Proposed Model ◽  
And Control ◽  
The Relationship ◽  
Fabrication Parameters ◽  
Good Agreement

The report “Brandon mathematical model describing the effect of calcination and reduction parameters on specific surface area of UO2 powders” [14] has built up a mathematical model describing the effect of the fabrication parameters on SSA (Specific Surface Area) of ex-AUC (Ammonium Uranyl Carbonate) UO2 powders. In the paper, the Brandon mathematical model that describe the relationship between the essential fabrication parameters [reduction temperature (TR), calcination temperature (TC), calcination time (tC) and reduction time (tR)] and SSA of the obtained ex-ADU (Ammonium Di-Uranate) UO2 powder product has established. The proposed model was tested with Wilcoxon’s rank sum test, showing a good agreement with the experimental parameters. The proposed model can be used to predict and control the SSA of ex-ADU UO2 powders

Predicting the Strength of Rectangular Reinforced Concrete Columns Confined with FRP Sheets

2022 ◽  
Vol 906 ◽  
pp. 17-23
Author(s):  
Ashot G. Tamrazyan ◽  
Yehia A.K. Sayed
Keyword(s):  
Compressive Strength ◽  
Regression Analysis ◽  
Concrete Columns ◽  
Test Results ◽  
Rc Columns ◽  
New Model ◽  
Proposed Model ◽  
Axial Compressive Strength ◽  
Frp Sheet ◽  
Good Agreement

A complete reorganization about the behavior of rectangular RC columns confined with FRP sheet is very important to predict the axial compressive strength values of the strengthened rectangular RC columns. That is because the process of strengthening RC rectangular column depending on several parameters that role this type of strengthening. These parameters include the characteristics of the used fiber, the grade of concrete and the geometry of the cross section including the rectangularity aspect ratio, corner radius, and size of specimens. Besides that, using a wide scope of experimental data may affect positively to generalize a model that considers the whole parameters affect the value of the axial strength. So, in this paper a review about parameters that affect the axial compressive strength values of rectangular RC columns was conducted. After that, based on the test results regarding FRP-confined rectangular RC columns available in the literature or conducted by the author, some existing confinement models for rectangular RC columns were assessed. Further, a new model is proposed through regression analysis of the database. A new model is proposed through regression analysis of the database. The proposed model was found to be in good agreement with the test results in the database. Finally, based on the results conclusions were drawn.

Study on Vertical Earth Pressure of Slab Culvert under High Embankment

2012 ◽  
Vol 256-259 ◽  
pp. 1898-1902 ◽  
Author(s):  
Bao Kuan Ning ◽  
He Fan ◽  
Lei Gong ◽  
Guo Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Conditions ◽  
Field Test ◽  
Structural Design ◽  
Earth Pressure ◽  
Test Results ◽  
Soil Pressure ◽  
Vertical Earth Pressure ◽  
The Impact ◽  
Good Agreement

With the increasing of embankment culvert engineering applications, there has been due in part to the structural design is too conservative and not economic or select unreasonable structural form, leading to the phenomenon of cracking or even collapse of the culvert structure, and the phenomenon has seriously affected the normal use of the highway. In this paper, the numerical simulation of vertical earth pressure distribution on different structural forms of embankment on culverts, to discuss the impact of boundary conditions, fill height, the thickness of the culvert culverts vertical earth pressure. Combined with Heda highway a culvert covert field test results and numerical simulation results were compared and analyzed. The results show that the numerical simulation and field test results in good agreement with the culvert structure in the form of vertical earth pressure of the embankment culverts have a greater impact; the structure of different forms of the culvert in the upper soil pressure is significantly different. In addition, analysis of the impact of boundary conditions, filling height of culvert vertical earth pressure values. The results can reference for the study of the structural design of the embankment culverts security.

Kinetic Model of Thermoelastic Martensite Transformation in Niti and NiMn Based Shape Memory Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
K. H. Wu ◽  
J.D. Shi ◽  
F. Yang ◽  
Z. J. Pu
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Quantitative Model ◽  
Proposed Model ◽  
Series Of Experiments ◽  
The Relationship ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTA new, quantitative model was developed to describe the martensite transformation kinetics of thermoelastic shape memory alloys (SMAs). In addition, a series of experiments were conducted to study the Kinetics of thermoelastic martensite transformation in four SMA systems: NiTi, NiTi-15at%Hf, NiTi-20at%Zr and NiMn-7.5at%Ti alloys. Comparisons between data of the kinetic of martensite transformation with the present theoretic models show that the proposed model is in good agreement and concurs with the experimental data. Also, a comparison of data from the proposed model with data from existing kinetic models, such as Liang's and Magee's [1,7], indicates that the proposed model can better describe the experimental data, including the relationship between dξ(T)/dT and ξ, and dξ(T)/dT and T.

The earth pressure behind full-height frame integral abutments supporting granular fill

2007 ◽  
Vol 44 (3) ◽  
pp. 284-298 ◽  
Author(s):  
Ming Xu ◽  
Chris RI Clayton ◽  
Alan G Bloodworth
Keyword(s):  
Particle Shape ◽  
Radial Strain ◽  
Earth Pressure ◽  
Length Change ◽  
Coarse Sand ◽  
Lateral Earth Pressure ◽  
The Earth ◽  
Granular Particle ◽  
Integral Abutments ◽  
Full Height

Compared with conventional bridges, integral bridges have no bearings or joints between the deck and abutments and thus can significantly reduce maintenance requirements and costs over the bridge's lifetime. However, there is uncertainty about the ultimate magnitude of the lateral earth pressure behind such abutments, as they are forced to move with the deck length change caused, for example, by daily and annual variations in the effective bridge temperature. This research investigated the earth pressure that would be expected to occur behind full-height frame integral abutments backfilled by granular materials. Radial strain-controlled cyclic stress path testing has been conducted on coarse sand specimens and a glass ballotini specimen. The results suggest that for integral abutments retaining uniform coarse sand, the lateral earth pressure will experience systematic increases for almost all cyclic strain levels, eventually reaching states of stress close to both active and passive. The mechanism of the buildup of lateral stress is explored, and it appears to be associated with nonspherical granular particle shape. The implications for frame integral abutment design are discussed.Key words: integral abutments, granular, particle shape, earth pressure, stiffness.

Comprehensive Nonlinear Modeling of a Pilot Operated Relief Valve

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Osama Gad
Keyword(s):  
Steady State ◽  
Coulomb Friction ◽  
Nonlinear Modeling ◽  
Critical Parameters ◽  
Relief Valve ◽  
Proposed Model ◽  
Mode Of Operation ◽  
Velocity Changes ◽  
Pressure Changes ◽  
Good Agreement

This paper is directed toward a comprehensive nonlinear modeling and simulation of the performance of a class of a pilot operated relief valves. A mathematical model is deduced to predict the performance of the valve in the steady state and transient modes of operations. The developed model takes into consideration most nonlinearities of the valve and is studied within the MATLAB-SIMULINK environment. The validity of the proposed model is assessed experimentally in the steady state and transient modes of operations. The detailed modeling has resulted in a good agreement between simulation and experimental results. During the simulation studied, it was found that, nonlinearity occurs due to three factors: the pressure changes cause nonlinear velocity changes of the flow rate, the throttling area of the valve restriction usually changes nonlinearly, and the discharge coefficient of the throttling area of the valve restriction does not remain constant. In the transient mode of operation, the simulation studied identified some critical parameters which have a significant effect on the transient response of the valve. Most of the model’s parameters can be evaluated readily by direct measurement of the valve components dimensions thought the Coulomb friction factor and bulk modulus are tuned to match the model to the measurements.

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