scholarly journals Vertical Vibrations of Footbridges Due to Group Loading: Effect of Pedestrian–Structure Interaction

2021 ◽  
Vol 11 (4) ◽  
pp. 1355
Author(s):  
Paweł Hawryszków ◽  
Roberto Pimentel ◽  
Rafaela Silva ◽  
Felipe Silva
Keyword(s):  
Dynamic Systems ◽  
Resonance Condition ◽  
Realistic Model ◽  
Vertical Vibration ◽  
Structure Interaction ◽  
Codes Of Practice ◽  
Vibration Serviceability ◽  
Vertical Vibrations ◽  
Pedestrian Crossing ◽  
Vibration Signatures

The vibration serviceability of footbridges has evolved from the adoption of a single pedestrian crossing in the resonance condition to load cases in which several pedestrians cross the structure simultaneously. However, in spite of this improvement, pedestrians continue to be considered as applied loads in codes of practice. Recent research has pointed out that modeling pedestrians as dynamic systems is a step further in the search for a more realistic design approach. This is explored in this paper, focusing on the case of vertical vibration. A two-span cable-stayed test structure was selected, and accelerations were measured from single and group crossings, both at the structure and at a pedestrian’s waist. Numerical simulations considering the pedestrians modeled as loads only and also as dynamic systems were implemented, and numerical and experimental time response vibration signatures were compared. Reductions of up to 25% and 20% in peak and RMS acceleration, respectively, were obtained when pedestrians were modeled as dynamic systems, in comparison with the less realistic model of pedestrians as loads only. Such reductions were shown to depend on the number of pedestrians involved in the group. The results, thus, highlight that pedestrian–structure interaction is an asset for the vibration serviceability design of footbridges.

Research of the Vertical Vibrations of Tandem Mill Based on Wavelet Analysis

2015 ◽  
Vol 724 ◽  
pp. 279-282
Author(s):  
Chun Hua Ren ◽  
Xu Ma ◽  
Ze Ming Li ◽  
Yan Hong Ding
Keyword(s):  
Wavelet Analysis ◽  
Wavelet Decomposition ◽  
Vibration Signal ◽  
Vertical Vibration ◽  
Rolling Speed ◽  
Vibration Data ◽  
Signal Features ◽  
Operating Side ◽  
Vertical Vibrations ◽  
Vibration Parameters

In this paper, the defect sheet was captured coincidentally. According to the defective product’s characteristics, we suspected to be caused by the vertical vibration of the roll. When the rolling speed reached a certain value, the vibration of the fourth stand can be feel. The experiment of the vibration data collection was taken to compare the vibration parameters of rolling operating side with those of drive side by wavelet analysis. The result states that the abnormal vibration signal features can be extracted in a special frequency segment of wavelet decomposition, and the vibration frequency to the roll is confirmed which appeared product defects.

scholarly journals Pulsating fields of a thin film in a static magnetic field under vertical vibrations

2021 ◽  
Vol 2103 (1) ◽  
pp. 012233
Author(s):  
I V Volodin ◽  
A A Alabuzhev
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Surface Wave ◽  
Film Thickness ◽  
Static Magnetic Field ◽  
Surface Profile ◽  
Vertical Vibration ◽  
Vibrational Amplitude ◽  
Gravitational Forces ◽  
Vertical Vibrations

Abstract In the present paper a dynamics of a thin ferrofluid film under the vertical vibration in a static magnetic field is examined. The vibrational amplitude is assumed to be greater than film thickness so that vibrational force is greater than magnetic and gravitational forces. The pulsating part and the averaged part of the hydrodynamics fields are obtained. The solution of pulsating part for the traveling surface wave is found. The equation for the averaged surface profile is found.

scholarly journals Effect of the Anti-Yaw Damper on Carbody Vertical Vibration and Ride Comfort of Railway Vehicle

2020 ◽  
Vol 10 (22) ◽  
pp. 8167
Author(s):  
Mădălina Dumitriu ◽  
Dragoș Ionuț Stănică
Keyword(s):  
Ride Comfort ◽  
Vertical Vibration ◽  
Theoretical Research ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
Damping Force ◽  
Comfort Index ◽  
Lateral Vibrations ◽  
Power Spectral ◽  
Vertical Vibrations

The theoretical research on means to reduce the vertical vibrations and improve the ride comfort of the railway vehicle relies on a mechanical model obtained from the simplified representation of the vehicle, while considering the important factors and elements affecting the vibration behaviour of the carbody. One of these elements is the anti-yaw damper, mounted longitudinally, between the bogie and the vehicle carbody. The anti-yaw damper reduces the lateral vibrations and inhibits the yaw motion of the vehicle, a reason for which this element is not usually introduced in the vehicle model when studying the vertical vibrations. Nevertheless, due to the position of the clamping points of the anti-yaw damper onto the carbody and the bogie, the damping force is generated not only in the yawing direction but also in the vertical and longitudinal directions. These forces act upon the vehicle carbody, impacting its vertical vibration behaviour. The paper analyzes the effect of the anti-winding damper on the vertical vibrations of the railway vehicle carbody and the ride comfort, based on the results derived from the numerical simulations. They highlight the influence of the damping, stiffness and the damper mounting angle on the power spectral density of the carbody vertical acceleration and the ride comfort index.

Simulations of a Truck Driving on a Flexible Bridge

1997 ◽  
Author(s):  
Olof Friberg ◽  
Peter Möller ◽  
Boris Thorvald
Keyword(s):  
Computer Program ◽  
Multibody Dynamics ◽  
Time Integration ◽  
Realistic Model ◽  
Bridge Structure ◽  
Control Logic ◽  
Structure Interaction ◽  
Time Stepping ◽  
Common Time ◽  
Vehicle Structure

Abstract In this work, the main object was to perform simulations using a realistic model of a truck and trailer passing over a flexible bridge structure. Two driving cases were considered: straight forward driving with and without braking. In the latter case control logic was used to distribute the braking torques to the wheel axles. A general multibody dynamics computer program, DADS, and its tire subroutines were interfaced with our FEM routines in order to create a vehicle/structure interaction computer program. A part of this process was to integrate different time stepping algorithms from the multibody dynamics and FEM disciplines into a “common” time integration procedure. Another part was to write code to search for finite elements where tire/structure interaction takes place.

A Review on Fluid Structure Interaction Modeling Using Bondgraph Method

2006 ◽  
Author(s):  
M. Afzaal Malik ◽  
Badar Rashid ◽  
Shahab Khushnood
Keyword(s):  
Dynamic Systems ◽  
Fluid Dynamic ◽  
Fluid Structure Interaction ◽  
Original Research ◽  
Hydraulic Motor ◽  
Comprehensive Review ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Formidable Challenge ◽  
Interaction Modeling

Modeling of complex multi-dynamic systems is a formidable challenge. Extensive research has already been carried out focusing on modeling of fluid flow using conventional techniques. This research paper aims at carrying out review on fluid structure interaction specifically adopting bondgraph approach. A comprehensive review, on modeling of fluid dynamic systems, osmosis and hydraulics, rotary piston hydraulic motor, with the help of bondgraph method is carried out. This will facilitate to explore important areas of original research using bondgraph method.

scholarly journals Human-structure interaction experiments to determine the dynamic properties of the standing human body in vertical vibration

Structures ◽  
2020 ◽  
Vol 26 ◽  
pp. 934-946 ◽  
Author(s):  
Raad Hashim ◽  
Tianjian Ji ◽  
Parthasarathi Mandal ◽  
Qingwen Zhang ◽  
Ding Zhou
Keyword(s):  
Human Body ◽  
Dynamic Properties ◽  
Vertical Vibration ◽  
Structure Interaction

The Influence of Geometry, Manufacturing Asymmetry and Asymmetric Excitation on Vertical Vibration of a Mechanical System

2013 ◽  
Vol 302 ◽  
pp. 429-434 ◽  
Author(s):  
Martin Svoboda ◽  
Josef Soukup
Keyword(s):  
Mathematical Model ◽  
Simple Model ◽  
Mechanical System ◽  
Complete Solution ◽  
Experimental Methods ◽  
Vertical Vibration ◽  
Numerical Results ◽  
Space System ◽  
Experimental Solution ◽  
Vertical Vibrations

The article deals with the analysis of vertical vibrations of symmetric and asymmetric systems (possibility of application on vibration of vehicles and machinery units flexibly loaded machines). Vibration solution was performed by using numerical and experimental methods on a simple model of a vehicle. The complete solution of a space system has been made. The aim of the work was to build a mathematical model and its solution with use of FEM. The experimental solution was used to verify the numerical results and their verification.

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