scholarly journals Bridge Damping Extraction Method from Vehicle–Bridge Interaction System Using Double-Beam Model

2021 ◽  
Vol 11 (21) ◽  
pp. 10304
Author(s):  
Fengzong Gong ◽  
Fei Han ◽  
Yingjie Wang ◽  
Ye Xia
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Traffic Flow ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Element Model ◽  
Beam Model ◽  
Modal Shape ◽  
Structural Dynamic ◽  
Double Beam

When vehicles interact with a bridge, a vehicle–bridge interaction (VBI) system is created. The frequency and modal shape of VBI systems have been widely studied, but the damping of VBI systems has not been adequately investigated. In recent years, several incidents of abnormal bridge vibration due to changes in bridge damping have occurred and aroused widespread concern in society. Damping is an important evaluation index of structural dynamic performance. Knowing the damping ratio of a VBI system is useful for analyzing the damping changes while a bridge is in service. This paper presents a method to extract bridge damping values from a VBI system, which can serve as a guide for bridge damping evaluation. First, a double-beam theoretical model was used to simplify the VBI system for cases involving uniform traffic flow. The damping ratio equation for the simplified VBI system was obtained using the extended dynamic stiffness method (EDSM). A double-beam finite element model and a VBI finite element model were established. The damping ratios of the two models were separately calculated and then compared with the simplified VBI model results. The results verified the accuracy of the simplified method. This paper then explains that bridge damping values can be extracted by estimating the equivalent traffic flow parameters and using the damping formula for the simplified VBI system. The bridge damping ratios extracted using this method in an engineering case ranged from 0.75% to 0.78%, which is smaller than the range that was directly identified using monitoring data (0.83–1.19%). The results show that the method can effectively extract bridge damping ratios and improve damping ratio identification.

Application of a FRF Based Model Updating Technique for the Validation of Finite Element Models of Components of the Automotive Industry

1995 ◽  
Author(s):  
Stefan Lammens ◽  
Marc Brughmans ◽  
Jan Leuridan ◽  
Ward Heylen ◽  
Paul Sas
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Automotive Industry ◽  
Stiffness Matrix ◽  
Model Updating ◽  
Dynamic Stiffness ◽  
Element Model ◽  
Model Parameters ◽  
Finite Element Models ◽  
Analytical Dynamic

Abstract This paper presents two applications of the RADSER model updating technique (Lammens et al. (1995) and Larsson (1992)). The RADSER technique updates finite element model parameters by solution of a linearised set of equations that optimise the Reduced Analytical Dynamic Stiffness matrix based on Experimental Receptances. The first application deals with the identification of the dynamic characteristics of rubber mounts. The second application validates a coarse finite element model of a subframe of a Volvo 480.

Identification of Dynamic Rates of Elastomeric Vibration Isolators in Automotive Vehicles

2004 ◽  
Author(s):  
Donald J. Nefske ◽  
Shung H. (Sue) Sung ◽  
Douglas A. Feldmaier
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Stiffness ◽  
Element Model ◽  
Interior Noise ◽  
Rear Suspension ◽  
Model Comparisons ◽  
Vibration Isolators ◽  
Vehicle System ◽  
Stiffness And Damping

Dynamic stiffness and damping rates of elastomeric vibration isolators used in automotive vehicles are identified from static isolator tests and the use of an isolator finite element model. Comparisons are made of the predicted versus measured dynamic stiffness and damping rates from 0 to 300 Hz of a rear suspension isolator to validate the technique. The identified dynamic rates of the elastomeric isolators of a representative vehicle are then input to the vehicle system finite-element model to compare the predicted versus measured vehicle vibration and interior noise response for laboratory shaker excitation.

scholarly journals A Study on Fluid Self-Excited Flutter and Forced Response of Turbomachinery Rotor Blade

2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
Chih-Neng Hsu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Power Plants ◽  
Single Mode ◽  
Element Model ◽  
Forced Response ◽  
Structural Dynamic ◽  
Turbine Engine ◽  
Forcing Function ◽  
Structural Dynamic Characteristics

Complex mode and single mode approach analyses are individually developed to predict blade flutter and forced response. These analyses provide a system approach for predicting potential aeroelastic problems of blades. The flow field properties of a blade are analyzed as aero input and combined with a finite element model to calculate the unsteady aero damping of the blade surface. Forcing function generators, including inlet and distortions, are provided to calculate the forced response of turbomachinery blading. The structural dynamic characteristics are obtained based on the blade mode shape obtained by using the finite element model. These approaches can provide turbine engine manufacturers, cogenerators, gas turbine generators, microturbine generators, and engine manufacturers with an analysis system to remedy existing flutter and forced response methods. The findings of this study can be widely applied to fans, compressors, energy turbine power plants, electricity, and cost saving analyses.

Updating of Finite Element Model in Considering Mode Errors with Fuzzy Theory

2009 ◽  
Vol 413-414 ◽  
pp. 785-792 ◽  
Author(s):  
Yang Liu ◽  
Zhong Dong Duan ◽  
Hui Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Fuzzy Theory ◽  
Dynamic Properties ◽  
Fuzzy Model ◽  
Element Model ◽  
Structural Dynamic ◽  
Fuzzy Variables ◽  
Design Variables

Finite element model updating aims at reconciling the analytical model with the test one, to acquire a refined model with high-fidelity in structural dynamic properties. However, testing data are inevitable polluted by noises. In this study, the mode parameters and design variables are modeled as fuzzy variables, and a fuzzy model updating method is developed. Instead of a single optimal model, a set of satisfactory models is obtained. The most physically compatible solution is sorted by insights to the structures. The proposed method is applied to a real concrete bridge, for which a physically meaningful model is identified.

scholarly journals FINITE ELEMENT MODEL OF DYNAMIC TRAIN-BRIDGE INTERACTION

2020 ◽  
Vol 22 (6) ◽  
pp. 154-166
Author(s):  
S. V. Efimov ◽  
K. O. Zhunev
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Properties ◽  
Accumulation Rate ◽  
Dynamic Stiffness ◽  
Oscillation Amplitude ◽  
Element Model ◽  
Operating Conditions ◽  
Railway Bridges ◽  
Bridge Span

Innovative heavy wagons with a 25–27 tf axle load and the freight train movement organization having a higher weight and length are being put into operation in Russia. New operating conditions of railway bridges require an assessment of bearing capacity, durability, accumulation rate of fatigue damage and reliability. The important parameters are the dynamic properties of railway bridges (frequencies and modes of natural vibrations, decay rate, dynamic stiffness).The aim of this work is to determine the dynamic interaction of trains having different structure, weight and length with a railway bridge using numerical modeling in the midas Civil bridge software. The proposed model is verified by the dynamic parameters of spans (natural vibration frequencies), which are determined during the bridge inspection using a Tensor-MS system.The modal analysis is given to the finite element model. The lowest natural modes of the bridge are determined. Based on numerical simulation of the interaction between the train and the bridge unfavorable speed of trains is calculated leading to an increase in the oscillation amplitude of the bridge span as well as in the bridge dynamic coefficient with regard to the design features of the train structure and composition.

Finite Element Analysis of Beams With Constrained Damping Treatment Modeled Via Fractional Derivatives

1997 ◽  
Vol 50 (11S) ◽  
pp. S216-S224 ◽  
Author(s):  
Luis E. Sua´rez ◽  
Arsalan Shokooh ◽  
Jose´ Arroyo
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Single Layer ◽  
Element Model ◽  
Beam Element ◽  
Element Formulation ◽  
Beam Model ◽  
Element Analysis ◽  
Damping Material ◽  
Derivatives Of

This paper presents a finite element formulation for the modeling of beams and frames with artificial damping provided by means of a constrained single layer of damping material. The behavior of the damping material is described using the fractional derivative model of viscoelasticity. In this model, the first order derivatives of the strains in the constitutive equations of the viscoelastic materials are replaced by derivatives of order α < 1. The finite element model developed is a one-dimensional beam element with three degrees of freedom per node. The dynamic response is calculated with a procedure involving a transformation of the original equations of motion to the state space and its decoupling with the eigenvectors of a special eigenvalue problem. The accuracy of the modal properties obtained with the beam model is compared with those calculated from a more elaborate plane stress finite element model. It was found that the proposed beam element provides very accurate results and with much lower computational costs than the 2-D model.

Ground Vibration Test Planning of a Fighter Aircraft by Using a Rough Finite Element Model

2013 ◽  
Author(s):  
Sertac Koksal ◽  
Erdinc Nuri Yildiz ◽  
Yigit Yazicioglu ◽  
Gokhan Osman Ozgen
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ground Vibration ◽  
Aircraft Design ◽  
Element Model ◽  
Fighter Aircraft ◽  
Structural Dynamic ◽  
Planning Stage ◽  
Certification Process ◽  
Flutter Testing

Certification process is one of the crucial procedures for safety in the design of a new aerial platform. Flight flutter testing is the most critical component for the certification process. Usually a flutter analysis is performed beforehand for the planning of flight flutter testing of an aircraft which mostly requires the Finite Element Model (FEM) together with Ground Vibration Testing (GVT) to construct the structural dynamic model of the complete aircraft for the flutter analyses. GVT is not only required for new aircraft design but also when considerable changes are made to an existing aircraft or when new external load configurations are introduced. Experimental methods require high effort, high budget, long time, and much repetition. Therefore, the computational and theoretical studies seem more applicable in the early phase. However, GVT of an available fighter aircraft in defense projects becomes an issue for the designers if a detailed FEM of the aircraft is not available prior to test. Hence, planning of the GVT in early stage is vital for project leaders. In this study, a rough FEM of a fighter aircraft is developed and correlated to available GVT data for planning purpose. The representative mode shapes are evaluated by estimation of the several sections of the aircraft. It is also shown that a rough FEM of the aircraft can be utilized for determination of the measurement and excitation points on the aircraft in planning stage. The geometrical properties, physical limitations and basic requirements of GVT are also taken into account for an efficient planning.

scholarly journals Damping Prediction Technique of the Bolted Joint Structure Considering Pretension Force

2015 ◽  
Vol 9 (1) ◽  
pp. 622-626
Author(s):  
Delin Sun ◽  
Ridong Liao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damping Ratio ◽  
Element Model ◽  
Experimental Result ◽  
Bolted Joint ◽  
Lap Joint ◽  
Joint Structure ◽  
Modal Damping ◽  
Prediction Approach

At the initial phase of the mechanical product development, it is very important to effectively obtain the modal damping ratio of the bolted joint structure for accurately predicting dynamic response. The energy dissipation has been estimated using a finite element model incorporating the effect of pretension force of the bolted joint. First, the modal damping ratios of the first four modes are extracted by experimental method. Secondly, the lap joint finite element model with pretension force parameter is constructed and based on which, modal analysis of the structure is conducted. The modal shape scaling results are used as the boundary conditions of the finite element model and the energy dissipations and modal damping ratios of the lap joint under different pretension forces are calculated out. By comparing the numerical calculation result and the experimental result, the validation of the damping prediction approach proposed in this paper is proved.

scholarly journals Influence of Non-Homogeneous Foundations On the Dynamic Responses of Railway Sleepers

2020 ◽  
pp. 2150002
Author(s):  
Le-Hung Tran ◽  
Tien Hoang ◽  
Denis Duhamel ◽  
Gilles Foret ◽  
Samir Messad ◽  
...  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Dynamic Stiffness ◽  
Substantial Reduction ◽  
Element Model ◽  
Dynamic Responses ◽  
Railway Track ◽  
Computational Time ◽  
Beam Model ◽  
The One

In a railway track, the sleeper’s responses on a non-homogeneous foundation have been investigated by researchers focusing on the foundation behavior along the rails. However, the foundation can also vary along the sleeper length, particularly when the track is newly tamped. The foundation at the sleeper center is often weaker than those under the rails and this non-homogeneity directly affects the sleeper responses. This paper presents a new model to calculate the influence of such foundations on the dynamic responses of the railway sleepers. This model is developed by combining a finite element model for the sleepers and foundation and a model of periodically supported beams subjected to moving loads for the rails. In this paper, the foundation contains three parts with different mechanical behaviors. The sleeper’s responses can be calculated by transforming the finite-element dynamic stiffness matrix to the one considering the boundary conditions and the relation between the rail seat forces and rail displacements governed by the beam model. This method reduces all the degrees of freedom of the railway track to its one period which gives a substantial reduction in computational time. The numerical applications show that the more homogeneous (so-called consolidated) the foundation is, the larger the sleeper strain is at its center. This result shows the potential application of the sleeper responses to estimating the consolidation level of the foundation.

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