scholarly journals DISPLACEMENT ANALYSIS OF SHEET PILE WITH TIE BEAM ON BREAKWATER CONSTRUCTION BY USING PLAXIS

2020 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Maulana Arif
Keyword(s):  
Dynamic Condition ◽  
Input Parameter ◽  
Main Tool ◽  
Static Condition ◽  
Wave Force ◽  
Ocean Waves ◽  
Sheet Pile ◽  
Sand Column ◽  
Open Sea ◽  
D Model

The breakwater construction usually founded in coastal area with many public or company facilities. It is very useful to break the ocean waves so it can not reach the shore line. Furthermore, the breakwater construction is also applied as a barier for a port for ship docked. One of the type of breakwaters is tube column filled with compacted sand reinforced by sheet file and tie beam. This research will discuss about the sheet pile displacement in static and dynamic condition. Plaxis is applied as the main tool to built the 2-D model based on given data from field observation. The input parameter for this model is applied in soil stratigraphy, compacted sand column, sheet pile, tie beam, pseudostatic wave force, sea level and earthquake acceleration. The running of this model divided in three condition. There are static condition, static condition with pseudostatic wave force, and dynamic condition. The results show different displacement between the conditions. The sheet pile displacement in static condition is 3.35 cm at harbor side and 1.91 cm at open sea. The sheet pile displacement in static condition with pseudostatic wave force is 12.14 cm at harbor side and 12.08 cm at open sea. The sheet pile displacement in dynamic condition has 5 cm peak both harbor side and open sea. 

scholarly journals Postural Control Disturbances Induced by Virtual Reality in Stroke Patients

2021 ◽  
Vol 11 (4) ◽  
pp. 1510
Author(s):  
Charles Morizio ◽  
Maxime Billot ◽  
Jean-Christophe Daviet ◽  
Stéphane Baudry ◽  
Christophe Barbanchon ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Postural Control ◽  
Virtual Environments ◽  
Center Of Pressure ◽  
Dynamic Condition ◽  
Static Condition ◽  
Stroke Patients ◽  
Post Stroke ◽  
Subacute Stroke

People who survive a stroke are often left with long-term neurologic deficits that induce, among other impairments, balance disorders. While virtual reality (VR) is growing in popularity for postural control rehabilitation in post-stroke patients, studies on the effect of challenging virtual environments, simulating common daily situations on postural control in post-stroke patients, are scarce. This study is a first step to document the postural response of stroke patients to different challenging virtual environments. Five subacute stroke patients and fifteen age-matched healthy adults were included. All participants underwent posturographic tests in control conditions (open and closed eyes) and virtual environment without (one static condition) and with avatars (four dynamic conditions) using a head-mounted device for VR. In dynamic environments, we modulated the density of the virtual crowd (dense and light crowd) and the avoidance space with the avatars (near or far). Center of pressure velocity was collected by trial throughout randomized 30-s periods. Results showed that more challenging conditions (dynamic condition) induced greater postural disturbances in stroke patients than in healthy counterparts. Our study suggests that virtual reality environments should be adjusted in light of obtaining more or less challenging conditions.

scholarly journals Fatigue Analysis of Aluminum Alloy Wheel Under Radial Load

2012 ◽  
pp. 112-117
Author(s):  
N. Satyanarayana ◽  
Ch. Sambaiah
Keyword(s):  
Shear Stress ◽  
Aluminum Alloy ◽  
Static Condition ◽  
Fatigue Analysis ◽  
Radial Load ◽  
Dimensional Model ◽  
Total Deformation ◽  
3 Dimensional ◽  
Alloy Wheel ◽  
D Model

In this paper a detailed “Fatigue Analysis of Aluminum Alloy Wheel under Radial Load”. During the part of project a static and fatigue analysis of aluminum alloy wheel A356.2 was carried out using FEA package. The 3 dimensional model of the wheel was designed using CATIA. Then the 3-D model was imported into ANSYS using the IGES format. The finite element idealization of this modal was then produced using the 10 node tetrahedron solid element. The analysis was performed in a static condition. This is constrained in all degree of freedom at the PCD and hub portion. The pressure is applied on the rim. We find out the total deformation, alternative stress and shear stress by using FEA software. And also we find out the life, safety factor and damage of alloy wheel by using S-N curve. S-N curve is input for a A.356.2 material.

scholarly journals A Measurement-Data-Driven Control Approach towards Variance Reduction of Micromachined Resonant Accelerometer under Multi Unknown Disturbances

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 294 ◽  
Author(s):  
Qiang Shen ◽  
Dengfeng Yang ◽  
Jie Zhou ◽  
Yixuan Wu ◽  
Yinan Zhang ◽  
...  
Keyword(s):  
Variance Reduction ◽  
Dynamic Condition ◽  
Measurement Data ◽  
Static Condition ◽  
Measurement Model ◽  
Data Driven ◽  
Least Mean Square ◽  
Accelerometer Sensor ◽  
Control Approach ◽  
Resonant Accelerometer

This paper first presents an adaptive expectation-maximization (AEM) control algorithm based on a measurement-data-driven model to reduce the variance of microelectromechanical system (MEMS) accelerometer sensor under multi disturbances. Significantly different characteristics of the disturbances, consisting of drastic-magnitude, short-duration vibration in the external environment, and slowly-varying, long-duration fluctuation inside the sensor are first constructed together with the measurement model of the accelerometer. Next, through establishing a data-driven model based on a historical small measurement sample, the window length of filter of the presented algorithm is adaptively chosen to estimate the sensor state and identify these disturbances simultaneously. Simulation results of the proposed AEM algorithm based on experimental test are compared with the Kalman filter (KF), least mean square (LMS), and regular EM (REM) methods. Variances of the estimated equivalent input under static condition are 0.212 mV, 0.149 mV, 0.015 mV, and 0.004 mV by the KF, LMS, REM, and AEM, respectively. Under dynamic conditions, the corresponding variances are 35.5 mV, 2.07 mV, 2.0 mV, and 1.45 mV, respectively. The variances under static condition based on the proposed method are reduced to 1.9%, 2.8%, and 27.3%, compared with the KF, LMS, and REM methods, respectively. The corresponding variances under dynamic condition are reduced to 4.1%, 70.1%, and 72.5%, respectively. The effectiveness of the proposed method is verified to reduce the variance of the MEMS resonant accelerometer sensor.

scholarly journals Wave interaction with Floating platform of different shapes and supports using BEM approach

2017 ◽  
Vol 14 (2) ◽  
pp. 115-133
Author(s):  
Anoop I. Shirkol ◽  
Nasar Thuvanismail
Keyword(s):  
Numerical Model ◽  
Elastic Plate ◽  
Wave Interaction ◽  
Wave Force ◽  
Ocean Waves ◽  
Wave Forces ◽  
Thin Elastic Plate ◽  
Floating Platform ◽  
Floating Elastic Plate ◽  
Different Shapes

Wave interaction with a floating thin elastic plate which can be used as floating platform is analyzed using Boundary Element Method (BEM) for different shapes such as rectangular, circular and triangular. Different support conditions are considered and the performance of the floating platform under the action of ocean waves is explored. The study is performed under the assumption of linearized water wave theory and the floating elastic plate is modelled based on the Euler-Bernoulli beam theory. Using Galerkin’s approach, a numerical model has been developed and the hydrodynamic loading on the floating elastic plate of shallow draft (thickness) is investigated. The wave forces are generated by the numerical model for the analysis of the floating plate. The resulting bending moment and optimal deflection due to encountering wave force is analysed. The present study will be helpful in design and analysis of the large floating platform in ocean waves.

scholarly journals A 3-D model for ocean waves over a Columb-damping poroelastic seabed

2004 ◽  
Vol 31 (5-6) ◽  
pp. 561-585
Author(s):  
M. Lin ◽  
D.-S. Jeng
Keyword(s):  
Ocean Waves ◽  
Poroelastic Seabed ◽  
D Model

Experimental Investigation of a New Derived Oleochemical Corrosion Inhibitor

2019 ◽  
Vol 796 ◽  
pp. 112-120
Author(s):  
Mysara Eissa Mohyaldinn ◽  
Wai Lin ◽  
Ola Gawi ◽  
Mokhtar Che Ismail ◽  
Quosay A. Ahmed ◽  
...  
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Corrosion Inhibition ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Dynamic Condition ◽  
Methyl Esters ◽  
Static Condition ◽  
Chemical Corrosion ◽  
Boron Fluoride

Most of the corrosion inhibitors that are used in industry contain chemicals that are harmful to health and environment. Corrosion inhibitors derived from green sources are, therefore, believed to be a good option for replacing the chemical corrosion inhibitors. In this work, a green oleochemical corrosion inhibitor derived from Jatropha Curcas is introduced. The paper discusses the methodology of deriving the corrosion inhibitor as well as the experimental test conducted for evaluating its corrosion inhibition efficiency. The new oleochemical corrosion inhibitor was derived via two reactions. Jatropha oil was firstly saponified with sodium hydroxide to yield gras acid and glycerol, which was then esterified with boron fluoride in presence of excess methanol to produce the oil methyl esters, which is used as oleo-chemical corrosion inhibitor. To evaluate the oleo-chemical corrosion inhibitor, the corrosion rate of mild steel in NaCl corrosive medium with CO2 is tested at static condition and two dynamic conditions, namely 500 and 1500 rpm. This is to simulate the transitional and turbulent flow in a pipeline. At each dynamic condition, the proposed corrosion inhibitor was tested at concentration dosages of 0, 50, 100, and 150 ppm. The experiments results revealed a good performance of the new oleochemical corrosion inhibitor. The inhibition efficiency was found to be highly affected by the concentration of corrosion inhibitor. Total corrosion inhibition of the mild steel was noticed by using 150 ppm at dynamic condition of 500 rpm.

Nonlinear System Identification in Offshore Structural Reliability

1995 ◽  
Vol 117 (3) ◽  
pp. 171-177 ◽  
Author(s):  
P. D. Spanos ◽  
R. Lu
Keyword(s):  
System Identification ◽  
Nonlinear System ◽  
Structural Reliability ◽  
Transfer Functions ◽  
Nonlinear System Identification ◽  
Simulated Data ◽  
Wave Force ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Analysis And Design

Nonlinear forces acting on offshore structures are examined from a system identification perspective. The nonlinearities are induced by ocean waves and may become significant in many situations. They are not necessarily in the form of Morison’s equation. Various wave force models are examined. The force function is either decomposed into a set of base functions or it is expanded in terms of the wave and structural kinematics. The resulting nonlinear system is decomposed into a number of parallel no-memory nonlinear systems, each followed by a finite-memory linear system. A conditioning procedure is applied to decouple these linear sub-systems; a frequency domain technique involving autospectra and cross-spectra is employed to identify the linear transfer functions. The structural properties and the force transfer parameters are determined with the aid of the coherence functions. The method is verified using simulated data. It provides a versatile and noniterative approach for dealing with nonlinear interaction problems encountered in offshore structural analysis and design.

Prediction of the Damping-Controlled Response of Offshore Structures to Random Wave Excitation

1980 ◽  
Vol 20 (01) ◽  
pp. 5-14 ◽  
Author(s):  
Kim J. Vandiver
Keyword(s):  
Wave Spectrum ◽  
Wave Force ◽  
Ocean Waves ◽  
Radiation Damping ◽  
Explicit Calculation ◽  
Random Wave ◽  
Wave Forces ◽  
Linear Wave ◽  
Radiation Wave ◽  
Diffraction Effects

Abstract A method is presented for predicting the damping-controlled response of a structure at a known natural frequency to random wave forces. The principal advantage of the proposed method over those in current use proposed method over those in current use is that explicit calculation of wave forces is not required in the analysis. This is accomplished by application of the principle of reciprocity: that the linear wave force spectrum for a particular vibration mode is proportional to the radiation (wave-making) proportional to the radiation (wave-making) damping of that mode. Several example calculations are presented including the prediction of the heave response of a prediction of the heave response of a tension-leg platform. The directional distribution of the wave spectrum included in the analysis. Introduction This paper introduces a simple procedure for estimating the dynamic response of a structure at each of its natural frequencies to the random excitation of ocean waves. The principal advantage of the proposed method is that the explicit calculation of wave forces has been eliminated from the analysis. This is made possible by a direct applications of the reciprocity relations for ocean waves, originally established by Haskind and described by Newman, in a form that is easy to implement. Briefly stated, fore many structures it is possible to derive a simple expression for the wave force spectrum in terms of the radiation damping and the prescribed wave amplitude spectrum. In general, such a substitution is of little use because the radiation damping coefficient may be equally difficult to find. However, the substitution leads to a very useful result when the dynamically amplified response at a natural frequency is of concern. In such cases it is shown that, contrary to popular belief, the response is not inversely proportional to the total damping but is, in fact, proportional to the ratio of the radiation damping to the total damping. Therefore, in the absence of a reliable estimate of either the total damping or the ratio of the radiation component to the total, an upper bound estimate of the response still may be achieved because of the existence of this upper bound is one of the key contributions of this paper.Linear wave theory is assumed; therefore, excitation caused by drag forces is not considered. However, for many structures drag excitation is negligible except for very large wave events. In the design process extreme events are modeled deterministically process extreme events are modeled deterministically by means of a prescribed design wave and not stochastically as is done here. In many circumstances linear wave forces will dominate, and the results shown here will be applicable. Although drag-exciting forces are not included, damping resulting from hydrodynamic drag is included. Wave diffraction effects are extremely difficult to calculate. This analysis includes diffraction effects but never requires explicit evaluation of them.It has been recognized that directional spreading of the wave spectrum is an important consideration in the estimation of dynamic response. In this paper such effects are accounted for in closed-form expressions. The evaluation of the expressions requires knowledge of estimates of the variation of the modal exciting force with wave incidence angle. However, only the relative variation of the modal exciting force as a percent of that at an arbitrarily chosen reference angle is required. Evaluation of the wave force in absolute terms still is not required. SPEJ p. 5

scholarly journals Research on Rubber Spring Model of High-speed EMU Based on Non-hyperelastic Forces

Mechanika ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 12-21
Author(s):  
Chuanbo XU ◽  
Maoru CHI ◽  
Liangcheng DAI ◽  
Yiping JIANG ◽  
Yongfa CHEN ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Prediction Accuracy ◽  
High Speed ◽  
Dynamic Condition ◽  
Static Condition ◽  
Good Prediction ◽  
Calculation Formula ◽  
Good Prediction Accuracy ◽  
Calculation Results ◽  
Better Than

The research on the mechanical model of rubber spring is one of the hot spots in train dynamics. In order to accurately calculate the viscoelastic force of the rubber spring, especially the non-hyperelastic forces (NHEF) part, a NHEF model is proposed based on the elliptic approximation method. Furthermore, the calculation formula of periodic energy consumption is put forward. The NHEF model is verified by experiments, and the function λ isconstructed to verify the formula of periodic energy consumption. The calculation results showed that the NHEF model had high accuracy in predicting the dynamic and quasi-static NHEF of rubber spring, the prediction accuracy of shear condition was better than that of compression condition, and the accuracy of quasi-static condition was better than that of dynamic condition; the calculation formula of periodic energy consumption had a good prediction accuracy in all working conditions.

scholarly journals Noninformative Vision of Body Movements can Enhance Tactile Discrimination

i-Perception ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 204166952110592
Author(s):  
Yosuke Suzuishi ◽  
Souta Hidaka
Keyword(s):  
Visual Information ◽  
Dynamic Condition ◽  
Discrimination Performance ◽  
Static Condition ◽  
The Body ◽  
Enhancement Effect ◽  
Body Parts ◽  
Body Movements ◽  
Tactile Discrimination ◽  
Noninformative Vision

Vision of the body without task cues enhances tactile discrimination performance. This effect has been investigated only with static visual information, although our body usually moves, and dynamic visual and bodily information provides ownership (SoO) and agency (SoA) sensations to body parts. We investigated whether vision of body movements could enhance tactile discrimination performance. Participants observed white dots without any textural information showing lateral hand movements (dynamic condition) or static hands (static condition). For participants experiencing the dynamic condition first, it induced a lower tactile discrimination threshold, as well as a stronger SoO and SoA, compared to the static condition. For participants observing the static condition first, the magnitudes of the enhancement effect in the dynamic condition were positively correlated between the tactile discrimination and SoO/SoA. The enhancement of the dynamic visual information was not observed when the hand shape was not maintained in the scrambled white dot images. Our results suggest that dynamic visual information without task cues can enhance tactile discrimination performance by feeling SoO and SoA only when it maintains bodily information.

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