Dynamic Modal Analysis of a Passenger Bus: Theoretical and Numerical Studies

2021 ◽  
pp. 036119812110288
Author(s):  
Rogério Lopes ◽  
Behzad V. Farahani ◽  
Francisco Q. de Melo ◽  
Nuno V. Ramos ◽  
Pedro M. G. P. Moreira
Keyword(s):  
Modal Analysis ◽  
Environmental Sustainability ◽  
Dynamic Models ◽  
Dynamic Assessment ◽  
Elastic Behavior ◽  
Fem Modeling ◽  
Simplified Approach ◽  
Safety Standards ◽  
The Road ◽  
Deformation Models

The dynamic assessment of a passenger bus is of the highest importance when aiming at high safety standards and low emissions for environmental sustainability. This work studies the dynamic response of a bus considering its modal analysis, for which simple dynamic models were developed for fast determination of the lowest frequencies, mainly arising from the suspension flexibility. In addition, complex natural vibration modes, impossible to determine using simplified models, were calculated via finite element method (FEM) modeling. To study the tire elastic behavior, as the key link between the vehicle and the road, specific deformation models, leading to a stiffness matrix to be combined with that of the vehicle spring suspension at each wheel/axis, were developed. This study aims at proposing a set of mathematical formulations to describe the modal behavior of passenger buses in detail, which could be applicable in any other long vehicle with similar conditions. Two main factors are studied, namely the suspension and the tire deformation effect. An acceptable agreement was verified between the simplified approach and FEM model results for the evaluation of natural frequencies and associated modes.

Modeling and Controlling of Anti-Slip Regulation Based on Limited-Slip Differential

2011 ◽  
Vol 86 ◽  
pp. 762-766
Author(s):  
Jian Jun Hu ◽  
Peng Ge ◽  
Zheng Bin He ◽  
Da Tong Qin
Keyword(s):  
Dynamic Models ◽  
Fuzzy Controller ◽  
Rear Wheel ◽  
Pi Controller ◽  
Hydraulic Control ◽  
Electronic Throttle ◽  
Adhesion Coefficient ◽  
The Road ◽  
Wheel Drive ◽  
Hydraulic Control System

The dynamic models of whole rear-wheel drive vehicle, limited-slip differential, hydraulic control system and electronic throttle were established. Simulations of acceleration course on split-µ road, checkerboard-µ road, low-µ road and step-µ road were carried out combining electronic throttle PI controller and limited-slip differential fuzzy controller. The results show that the Anti-slip Regulation quickly works according to the road adhesion coefficient, effectively inhibits the slip of driving wheels on low adhesion coefficient road, the acceleration performance driving on bad roads was improved obviously, and show a good adaptability.

scholarly journals A Double Sky-Hook Algorithm for Improving Road-Holding Property in Semi-Active Suspension Systems for Application to In-Wheel Motor

2021 ◽  
Vol 11 (19) ◽  
pp. 8912
Author(s):  
Seunghoon Woo ◽  
Donghoon Shin
Keyword(s):  
Computer Simulations ◽  
Dynamic Models ◽  
Active Suspension ◽  
The Other ◽  
Driving Mode ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Main Disadvantage ◽  
Advanced Development

This paper presents a double sky-hook algorithm for controlling semi-active suspension systems in order to improve road-holding property for application in an in-wheel motor. The main disadvantage of the in-wheel motor is the increase in unsprung masses, which increases after shaking of the wheel, so it has poor road-holding that the conventional theoretical sky-hook algorithm cannot achieve. The double sky-hook algorithm uses a combination of damper coefficients, one from the chassis motion and the other from the wheel motion. Computer simulations using a quarter and full car dynamic models with the road conditions specified by ISO2631 showed the effectiveness of the algorithm. It was observed that the algorithm was the most effective in the vicinity of the wheel hop frequency. This paper also proposed the parameter set of the double sky-hook algorithm to differentiate the driving mode of vehicles under advanced development.

Evaluation of Dynamic Characteristics of Masonry Arch Bridges: Linking Full-Scale Experiment and FEM Modeling

2010 ◽  
Vol 133-134 ◽  
pp. 605-610 ◽  
Author(s):  
Joanna M. Dulinska
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Spectral Density Function ◽  
Fem Modeling ◽  
Masonry Arch ◽  
The Road ◽  
Power Spectral ◽  
Impulse Load ◽  
Scale Experiment ◽  
Arch Bridges

The paper presents calculated and experimentally determined dynamic characteristics of masonry arch bridges. Two bridges were considered: the road viaduct at Zaborow and the bridge at Kamienica Dolna (South Poland). Finite element models were built considering all parts of the structures: arch, spandrel walls, fill, soil-structure interaction. For verification of calculations in situ investigations of dynamic characteristics of bridges were conducted. As a basic ways of realization of dynamic loads impulse load (drop of a lorry wheels from a threshold) as well as kinematic excitation (train passage under the viaduct) were applied. For determination of natural frequencies power spectral density function and transfer function of measured signals were applied. Basing upon the recorded vibrations the value of logarithmic decrement of damping was evaluated. The results of measured and calculated natural frequencies were compared. With regard to the degree of complexity of structures the differences between experimental and computational results can be accepted.

Experimental modal analysis for dynamic models of spacecraft

1991 ◽  
Vol 14 (3) ◽  
pp. 686-688 ◽  
Author(s):  
Keiji Komatsu ◽  
Masaaki Sano ◽  
Takashi Kai ◽  
Akio Tsujihata ◽  
Hidehiko Mitsuma
Keyword(s):  
Modal Analysis ◽  
Dynamic Models ◽  
Experimental Modal Analysis

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Identification and Significance of the First Structural Modes of Vibration of Two Wheeled Vehicles

2010 ◽  
Author(s):  
Alberto Doria ◽  
Luca Trombetta ◽  
Roberto Pegoraro
Keyword(s):  
Modal Analysis ◽  
Rigid Bodies ◽  
Elastic Behavior ◽  
Local Modes ◽  
System Of Rigid Bodies ◽  
Swing Arm ◽  
Modes Of Vibration ◽  
Small Set ◽  
Vehicle Chassis ◽  
Motorcycle Dynamics

In motorcycles and scooters the structural modes of vibration are important because they influence both vehicle’s comfort and vehicle’s stability and handling. Some researchers have shown that instabilities, which may occur when the vehicle is running (weave and wobble), are influenced by the modes of vibration, of the vehicle. At the Motorcycle Dynamics Research Group of Padova University many motorcycles have been tested with the method of modal analysis. The results of this research highlight that the whole motorcycle is a complex system that shows many kinds of modes of vibration: rigid modes, in which the structural components of the vehicle (chassis, fork, handlebars) behave as rigid bodies and deflection is given by tires and suspensions; local modes, in which deflection is concentrated in some subsystem of the vehicle (e.g. handlebars) and the rest of the motorcycle behaves as a system of rigid bodies; global modes with relevant deflection of the whole vehicle. This paper focuses on a specific issue, which is important for motorcycle design: the identifications of the frequencies of the first modes that show relevant deflection of the front fork and swing-arm. First, experimental equipment and testing methods are presented and discussed. Then the modal properties (natural frequencies, damping coefficients and modal shapes) of four motorcycles of different categories are presented, the characteristics of some modes are highlighted. Finally, the paper focuses on the identification of the frequencies that represent the borderline between rigid and elastic behavior of front fork and swing-arm. A method that requires the analysis of the characteristics of a small set of frequency response functions, without carrying out a long and expensive modal analysis of the whole vehicle, is presented. It is based on the properties of rigid modes (variation in vibration amplitude along a set of measurement points).

scholarly journals Testing Photovoltaic Pavers for Roadway Applications

2019 ◽  
Vol 4 (2) ◽  
pp. 86 ◽  
Author(s):  
Ronald A. Coutu, Jr. ◽  
David Newman ◽  
James Crovetti ◽  
Ashish Kumar Mishra ◽  
Mohiuddin Munna ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Construction Materials ◽  
Extreme Temperature ◽  
Cost Savings ◽  
Motor Vehicles ◽  
Safety Standards ◽  
Pavement Materials ◽  
Roadway Construction ◽  
Materials Used ◽  
Dynamic Loading Conditions

<p><em>Concrete and asphalt are the primary materials used to construct roadways for motor vehicles, bike paths for pedestrians and bicyclists, and runways for aircraft. Solar Roadways®, Inc. (SR) in Sandpoint, ID, proposed using robust, Solar Road Panels (SRPs) as an alternative roadway material due to the potential for creating a modular, multi-functional infrastructure product with cost-savings, user-safety, power-generation, and a better alternative in terms of environmental sustainability when compared to contemporary pavement materials. Typical roadway construction materials, on average, need to be replaced every 10-15 years while also requiring regular annual maintenance to maintain proper safety standards. SR’s novel roadway material is intended to extend roadway replacement timelines, lower annual maintenance costs, and provide energy to the power grid. In this study, we tested the mechanical properties of the “SR3” model prototype SRP and evaluated its suitability as a replacement roadway material with the added benefit of generating electric power. Specifically, we tested this unique pavement material in submerged water environments, under extreme temperature conditions, and under dynamic loading conditions.</em></p>

scholarly journals Specifics of road safety inspection in tunnels

2021 ◽  
Vol 67 (3) ◽  
pp. 33-38
Author(s):  
Emir Smailovic ◽  
Boris Antić ◽  
Dalibor Pešić ◽  
Slaviš Beronja
Keyword(s):  
Energy Efficiency ◽  
Road Safety ◽  
Traffic Accident ◽  
Road Network ◽  
Road Traffic ◽  
State Of The Art ◽  
Safety Standards ◽  
The Road ◽  
Road Users ◽  
Road Tunnels

Tunnels are underground passages, placed horizontally, which serve to lead the road through them. In order to fulfill its purpose in road traffic, the tunnel must fit into the traffic infrastructure and as such not create an obstacle in movement and enable the movement of vehicles from entrance to exit without danger, but with increased restriction of freedom of lateral evacuation. Tunnels are among some of the most risky parts of the road network, primarily due to space constraints, where there is a possibility of a traffic accident. Managing the risks associated with the passage of road traffic, and in particular the safety of traffic in tunnels, is a serious problem in many countries. With the growing number of road users, it is necessary to adopt stricter standards regarding road tunnels. In addition to meeting these safety standards, factors such as operational requirements, economic efficiency, energy efficiency and state-of-the-art technology should also be taken into account when planning and equipping tunnels.

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