scholarly journals Excellent Performance of Earth Dams under Resonance Motion Using Isolator Damping Layer

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Behrouz Gordan ◽  
Azlan Adnan
Keyword(s):  
Scale Parameter ◽  
Free Vibration Analysis ◽  
Dominant Frequency ◽  
Earth Dam ◽  
Soil Mechanic ◽  
Seismic Zone ◽  
River Sand ◽  
Earthquake Effect ◽  
Small Models ◽  
Thickness Layer

The effect of blanket layer using isolator damping layer (IDL) between river sand foundation and short embankment to remove damage under severe earthquake was investigated in the present study. In case of numerical analysis by ANSYS program, dominant frequency (DF) was computed by free vibration analysis. Soil mechanic tests for thirteen samples to design IDL formula were carried out. In terms of critical condition for earthquake effect such as resonance, five physical small models were tested using vibrator table under the dominant frequency with scale parameter 1/100. As a result, dam was significantly damaged without blanket layer IDL. In order to reduce damage, the best performance was observed using blanket layer (IDL) when this layer was expanded below the reservoir region. The reinforced thickness layer size is one-fourth of dam height. This method is a novel suggestion for earth dam design in seismic zone.

Vibration Analysis of Anisotropic Simply Supported Plates by Using Variable Kinematic and Rayleigh-Ritz Method

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Erasmo Carrera ◽  
Fiorenzo Adolfo Fazzolari ◽  
Luciano Demasi
Keyword(s):  
Vibration Analysis ◽  
Ritz Method ◽  
Single Layer ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Virtual Displacement ◽  
Simply Supported ◽  
Order Expansion ◽  
Thickness Layer ◽  
Made In

This work deals with accurate free-vibration analysis of anisotropic, simply supported plates of square planform. Refined plate theories, which include layer-wise, equivalent single layer and zig-zag models, with increasing number of displacement variables are take into account. Linear up to fourth N-order expansion, in the thickness layer-plate direction have been implemented for the introduced displacement field. Rayleigh-Ritz method based on principle of virtual displacement is derived in the framework of Carrera’s unified formulation. Regular symmetric angle-ply and cross-ply laminates are addressed. Convergence studies are made in order to demonstrate that accurate results are obtained by using a set of trigonometric functions. The effects of the various parameters (material, number of layers, and fiber orientation) upon the frequencies and mode shapes are discussed. Numerical results are compared with available results in literature.

scholarly journals In-process detection of fiber cutting in low consistency refining based on measurement of forces on refiner bars

TAPPI Journal ◽  
2017 ◽  
Vol 16 (04) ◽  
pp. 189-199 ◽  
Author(s):  
R. Harirforoush ◽  
J. Olson ◽  
P. Wild
Keyword(s):  
Fiber Length ◽  
Scale Parameter ◽  
Threshold Value ◽  
Dominant Frequency ◽  
Sensor Data ◽  
Weibull Function ◽  
Pulp Fibers ◽  
Major Drawback ◽  
Normal Forces ◽  
Process Detection

A major drawback of low consistency refining is the degradation of mechanical properties due to fiber cutting at high refining energies. Conventional strategies to avoid fiber cutting are based on post-refining measurement of pulp properties and, typically, this does not enable rapid adjustment of refiner operation in response to the onset of fiber cutting. The objective of this study is to detect the onset of fiber cutting by using custom-designed piezoelectric force sensors that measure shear and normal forces applied to pulp fibers by the refiner bars. Trials are performed in an AIKAWA/Advanced Fiber Technologies Inc. 16-in. single-disc low consistency refiner. The trials are run using mechanical softwood SPF (spruce, pine, and fir) pulp with 378 ml CSF at 2.5% and 3.5% consistency at rotational speeds of 800 rpm, 1000 rpm, and 1200 rpm. Distributions of the peak normal and shear forces and peak coefficient of friction are determined for each operating condition, and a two-parameter Weibull function is fit to each of these distributions. The scale parameter, which is one of the key parameters of the Weibull function, is calculated, and length-weighted fiber length is plotted as a function of this parameter. The results show that the onset of fiber cutting consistently corresponds to a distinct transition in the plot of length-weighted fiber length versus scale parameter. This transition is believed to be caused by a fundamental transition in the fiber-bar interaction. Moreover, frequency analysis of the sensor data shows that the magnitude of the dominant frequency remains relatively constant while the plate gap is reduced, up to a threshold value, which corresponds to the onset of fiber cutting. These results suggest that these sensors have potential to be used for in-process detection of the onset of fiber cutting.

scholarly journals Stability Assessment of Zoned Earth Dam under Water Particles Fluidity Effect: Hemren Dam as Case Study

2021 ◽  
Vol 79 (2) ◽  
pp. 27-38
Author(s):  
Saad Shauket Sammen ◽  
Marwah Qaddoori Majeed ◽  
Qutaiba G. Majeed
Keyword(s):  
Numerical Modeling ◽  
Water Level ◽  
Seismic Response ◽  
Factor Of Safety ◽  
Water Levels ◽  
Earth Dam ◽  
Seismic Zone ◽  
Earth Dams ◽  
The Core

Recently the numerical modeling using finite element method is take into account as a very effective tool to investigate the desired behavior of structures in geotechnical engineering. Earth dams are a water retention structures that are normally wide constructed around the world due to its significant features. These structures may be failed due to exposure to an earthquake and this will result in disaster. The main objective of this study is to assess the slope stability and the seismic response of an earthen dam. Since the matter of seismic response is still have a considerable lack of information for earth dams as a unique structure. Hemren zoned earth dam that is located in Diyala governorate, northeast of Iraq that considered as an active seismic zone has been considered as case study. Numerical modeling has been done in this study using Geo studio software. Factor of safety was calculated with different water levels in order to evaluate the dam safety with different operation water level. The excited earthquake is Elcentro while three values of peak ground acceleration were used which are 0.2, 0.25 and 0.3 g and the duration time is scaled to 10 seconds. In addition, three key points (at the core, the shell and the foundation) that represent the dam construction material are used to evaluate the dynamic response within the dam body. The results revealed that the factor of safety is increased when the water level is increase, but in the increasing in the magnitude of factor of safety with water depths of (10 and 15) m was more than the other depth. The zone of the dam core shows a negative pore water pressure value. That leads to an increasing in effective stress at the core of the dam.

The Optimized Dynamic Behavior of Short Embankment Based on Frequency Performance

2015 ◽  
Vol 6 (2) ◽  
pp. 1-11
Author(s):  
Behrouz Gordan ◽  
Azlan Adnan
Keyword(s):  
Response Spectrum ◽  
New Technology ◽  
Free Vibration Analysis ◽  
Horizontal Displacement ◽  
Relative Displacement ◽  
Dominant Frequency ◽  
Modulus Ratio ◽  
Depth Ratio ◽  
Vertical Displacements ◽  
The Impact

Due to the performance of embankment under the earthquake, relative displacement at both edges of the crest is very important for body cracks. It can be computed by dynamic analysis. In this way, response spectrum analysis and Rayleigh damping coefficient are dependent factors to dominant frequency. Based on the new technology using advanced programs to compute frequency, free vibration analysis as the basic technique and considering of different vibration modes is accessible. This research tried to evaluate the distribution of dominant frequencies for short embankment (H=30 meter) using Finite-Element Method (ANSYS 13). To evaluate of the frequency, elasticity modulus ratio and foundation depth ratio were the main objectives. Both were defined by the ratio between the embankment and foundation. As a result, maximum and minimum vertical displacements were located on both slopes, and maximum horizontal displacement was exposed at the crest. The dominant frequency increased as the modulus ratio decreased. In addition, dominant frequency decreased as the depth ratio increased. The impact of the modulus ratio to enhance frequency was greater than the depth ratio. In terms of contributing engineering, the amplitude of the dominant frequency (Hz) was finally optimized for modulus ratios (0.25-1.00) and depth ratios (0.1-1.00). For critical situation, modulus ratio was more than three, and the depth ratio was half of the unit. More research about medium embankment is recommended.

scholarly journals Critical State of Sand Matrix Soils

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Aminaton Marto ◽  
Choy Soon Tan ◽  
Ahmad Mahir Makhtar ◽  
Tiong Kung Leong
Keyword(s):  
Critical State ◽  
Kaolin Clay ◽  
Soil Mechanic ◽  
Test Apparatus ◽  
River Sand ◽  
Liquefaction Susceptibility ◽  
Reconstituted Soil ◽  
Isotropic Consolidation ◽  
The Relationship ◽  
Critical State Parameters

The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters,M,λ, andΓ. The range of the value ofM,λ, andΓis 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

Modeling Vibration-Induced Tire-Pavement Interaction Noise in the Mid-frequency Range

2020 ◽  
Author(s):  
Sterling McBride ◽  
Ricardo Burdisso ◽  
Corina Sandu
Keyword(s):  
Sound Intensity ◽  
Element Model ◽  
Dominant Frequency ◽  
Contact Forces ◽  
Surface Velocity ◽  
New Wave ◽  
Normal Surface ◽  
Radiated Noise ◽  
Physical Effects ◽  
Effects Of Rotation

ABSTRACT Tire-pavement interaction noise (TPIN) is one of the main sources of exterior noise produced by vehicles traveling at greater than 50 kph. The dominant frequency content is typically within 500–1500 Hz. Structural tire vibrations are among the principal TPIN mechanisms. In this work, the structure of the tire is modeled and a new wave propagation solution to find its response is proposed. Multiple physical effects are accounted for in the formulation. In an effort to analyze the effects of curvature, a flat plate and a cylindrical shell model are presented. Orthotropic and nonuniform structural properties along the tire's transversal direction are included to account for differences between its sidewalls and belt. Finally, the effects of rotation and inflation pressure are also included in the formulation. Modeled frequency response functions are analyzed and validated. In addition, a new frequency-domain formulation is presented for the computation of input tread pattern contact forces. Finally, the rolling tire's normal surface velocity response is coupled with a boundary element model to demonstrate the radiated noise at the leading and trailing edge locations. These results are then compared with experimental data measured with an on-board sound intensity system.

Investigational Studies on Quantity of Salinity in Netravati River Estuary Sand-Coastal Karnataka

2018 ◽  
Vol 6 (6) ◽  
pp. 46
Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu
Keyword(s):  
Brackish Water ◽  
Sea Water ◽  
Salt Water ◽  
Construction Material ◽  
Salt Content ◽  
River Estuary ◽  
Sand Sample ◽  
River Sand ◽  
Natural Aggregates

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.

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