scholarly journals Influences of Two Calculation Methods about Dynamic Tension on Vibration Characteristics of Cable-Bridge Coupling Model

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Guangyun Min ◽  
Xiaohui Liu ◽  
Chuan Wu ◽  
Shuguang Yang ◽  
Mengqi Cai
Keyword(s):  
Bridge Deck ◽  
Multiple Scales ◽  
Nonlinear Coefficient ◽  
Coupling Model ◽  
Vibration Characteristics ◽  
Parameter Analysis ◽  
Calculation Methods ◽  
Dynamic Tension ◽  
Linear Coefficient ◽  
Vibration Equation

For the cable-bridge coupling model, the dynamic tension of cables is an important parameter to study the vibration characteristics of the model. Based on this concept, two calculation methods about dynamic tension of cables were introduced in great detail, and the influences of these two calculation methods on the vibration characteristics of cable-bridge coupling model were systematically investigated. Firstly, the vibration equation of the cable was derived based on the variational principle for Hamiltonian, and the vibration equation of the bridge deck was obtained by Newton’s law. Then, the vibration equation of the cable and bridge deck was transformed into ordinary differential vibration equation by the Galerkin method. In addition, the differences of the coefficients in the ordinary differential vibration equation obtained by these two calculation methods about dynamic tension were compared, and a parameter analysis was listed. Finally, the resonance mode of the cable-bridge coupling model was analyzed by a multiple scales method, and an example analysis was listed. The results of parameter analysis show that there are obvious differences in the linear coefficient and nonlinear coefficient of the ordinary differential vibration equation obtained by these two calculation methods. The results of example analysis show that, for the cable-bridge coupling model with 1 : 1 resonance, the amplitude of the model would not be different because of the two calculation methods about dynamic tension, but the amplitude of the cable would be affected by the calculation method significantly. It can be found that the research conclusions here can be helpful to the perfection of theoretical modeling and has certain guiding value for practical engineering.

Research on Vibration Characteristics of Barrel Considered Gas Pressure

2015 ◽  
Vol 727-728 ◽  
pp. 501-504 ◽  
Author(s):  
Da Wei Zhu ◽  
Jie Zhou ◽  
Xue Ping Zhang
Keyword(s):  
Transverse Vibration ◽  
Great Influence ◽  
Forced Response ◽  
Vibration Characteristics ◽  
Gas Pressure ◽  
Charge Weight ◽  
Considerable Influence ◽  
Analysis Method ◽  
Vibration Equation ◽  
Simulation Results

The vibration of barrel has considerable influence on accuracy when firing, for obtaining the disciplinarian of barrel vibration, barrel is considered as a cantilever in this paper, on that base, its transverse vibration equation has been established, and forced response can be figured out by using modal analysis method. The vibration characteristics of barrel were numerically simulated for different charge weight, besides, two situations that the barrel with or without gas pressure have been compared. In solving process, the displacement、velocity and acceleration of projectile are real dates. The simulation results indicate that static offset has a great influence on vibration characteristics, with the increasing of the projectile′s initializing speed, the amplitude of the barrel′s vibration is lower without static offset, and the effect of gas pressure can decrease the amplitude of vibration considerably.

Buckling Strength and Parameter Analysis on Stiffened Flange Plate under Compression

2013 ◽  
Vol 838-841 ◽  
pp. 1159-1164
Author(s):  
Wen Ru Lu ◽  
Jin Di
Keyword(s):  
Highway Bridges ◽  
Parameter Analysis ◽  
Steel Bridge ◽  
Design Codes ◽  
Test Results ◽  
Calculation Methods ◽  
Buckling Strength ◽  
Calculation Results ◽  
Design Theories ◽  
Plate Width

The buckling strength of stiffened flange plate under compression was researched by referring to BS5400, Japanese Specification for Highway Bridges and Eurocode in order to research calculation methods of stiffened flange plate under compression in foreign design codes of steel bridge which were based on different design theories. Test results of ultimate bearing capacity of stiffened flange plate under compression were compared with calculation results according to those codes. The effects of constructive parameters such as the thickness of flange plate, width of subpanel, thickness of plate and width of inclined web plate in rib on buckling strength of stiffened flange plate under compression were researched respectively. The results showed, when increasing the thickness of flange or decreasing the width of plate divided by rib's web, calculation results of buckling strength increased at first and then leveled off according to Japanese Specification for Highway Bridges. However the buckling strength declined slowly according to BS5400 and Eurocode. When increasing the thickness of plate or decreasing the width of inclined web plate of rib, calculation results increased at the beginning and leveled out then. If ribs satisfy the rigidity demands, calculation results of buckling strength would remain the same as the sizes of rib were changed according to Japanese Specification for Highway Bridges.

Nonlinear Vibration Control of Flexible Structures Using Nonlinear Modified Positive Position Feedback Approach

2014 ◽  
Author(s):  
Ehsan Omidi ◽  
S. Nima Mahmoodi
Keyword(s):  
Multiple Scales ◽  
Flexible Structures ◽  
Primary Resonance ◽  
Oscillatory System ◽  
Parameter Analysis ◽  
Superior Performance ◽  
Closed Loop System ◽  
Positive Position Feedback ◽  
Position Feedback ◽  
Nonlinear Vibration Control

A new Nonlinear Modified Positive Position Feedback (NMPPF) controller is proposed in this paper to suppress the nonlinear resonant vibrations in flexible structures. The NMPPF uses a nonlinear second-order feedback compensator to overcome the vibrations at exact primary resonance frequency, and a first-order integrating term to lower the remaining peak amplitudes in the frequency domain. For the closed-loop system, an innovative implementation of the Method of Multiple Scales is employed to obtain the modulation equations. Results demonstrate the superior performance of the NMPPF controller compared to the conventional approach i.e. Positive Position Feedback (PPF), as the suppression performance is improved by 62% in the peak amplitude reduction. The presented parameter analysis of the NMPPF controller also proposes the optimal controller parameters to provide the highest suppression level in the nonlinear oscillatory system.

scholarly journals A Vibration Similarity Model of Converter Transformers and Its Verification Method

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 143
Author(s):  
Hao Wang ◽  
Li Zhang ◽  
Youliang Sun ◽  
Guan Wang ◽  
Liang Zou
Keyword(s):  
Similarity Criterion ◽  
Reference Value ◽  
Coupling Model ◽  
Vibration Characteristics ◽  
Magnetic Flux Density ◽  
Verification Method ◽  
Distribution Shape ◽  
Similarity Model ◽  
Before And After ◽  
Flux Density Distribution

According to the vibration characteristics of converter transformers, considering the Maxwell equation, magnetostrictive effect, Lorentz force and structural mechanics, the similarity criterion suitable for converter transformers is deduced in this paper. Using the finite element simulation platform, the multi physical field coupling model of converter transformers is constructed, and the scale coefficient is 0.1. The magnetic flux density distribution, stress distribution, shape variable and vibration characteristics of the model before and after the similarity are analyzed. The results show that the variation law of the model before and after the similarity conforms to the similarity criterion, and the correctness of the similarity criterion is verified. The converter transformer vibration similarity model and its verification method can effectively reduce the unnecessary waste of resources before the preparation of converter transformers and have important reference value for the analysis and improvement of converter transformer vibration characteristics.

Analysis of transmission box vibration characteristics under random road torsional excitation

2021 ◽  
pp. 095440702110642
Author(s):  
Shengping Fu ◽  
Shanming Luo ◽  
Hanlin Huang
Keyword(s):  
Dynamic Response ◽  
Simulation Method ◽  
Coupling Model ◽  
Step Length ◽  
Vibration Characteristics ◽  
Road Surface ◽  
Test Scheme ◽  
Superposition Method ◽  
Coupling Mechanism ◽  
Torsional Excitation

Random road torsional excitation is a key excitation condition for transmission box vibration of tracked vehicles. In order to accurately analyze influences of random road torsional excitation on the vibration characteristics of the transmission box, a calculation method of this excitation for tracked vehicle is proposed based on the random expression of the roughness of standard road surface. Furthermore, random road torsional excitations under different road grades and vehicle speeds are simulated. With the finite element method and modal superposition method, the box body is discretized, and the elastic characteristics of the box body are characterized to explore the dynamics coupling mechanism of gear shafting and the box body. By considering bending-torsional coupling vibration of gear shafting under multi-source excitations, such as the fluctuated torque of engine and dynamic meshing stiffness of gears, dynamic coupling model of gear shafting and box body under random road torsional excitation is established. The dynamic response of the gearbox under random road torsion excitation is obtained by co-simulation with the variable step length Runge-Kutta method. Influences of different road grades, track preload and vehicle speeds on dynamic response characteristics of the gearbox are analyzed. Real vehicle road test scheme is designed to obtain surface acceleration response of the box body at different speeds on the cement road surface. Both test and simulation results are compared and analyzed to verify the accuracy of the simulation method, which provides a theoretical reference for dynamic optimization of the transmission box.

Study of Dynamic Analysis Model on Subway Vehicle-Tunnel Vertical Coupled System

2012 ◽  
Vol 170-173 ◽  
pp. 1497-1503
Author(s):  
Bo Liang ◽  
Hong Luo ◽  
Wei Qing
Keyword(s):  
Dynamic Analysis ◽  
Coupled System ◽  
Coupling Model ◽  
Vertical Vibration ◽  
The Body ◽  
Analysis Model ◽  
Vibration Equation ◽  
Vibration Model ◽  
Dynamic Coupling Model ◽  
Tunnel System

In this paper, vehicle systems and track-tunnel system are regarded as an interactional, mutual coupling overall system and the interaction between wheel and rail is regarded as the “ligament” of these two subsystems. The vehicle vibration model and vibration equation are established by considering the body vertical vibration, a suspension of vertical vibration and wheelset vertical vibration. By the displacement compatibility condition of the vehicle and track, integrating the vehicle equations and discretized track-tunnel vibration equation, the dynamic coupling model and the equations that reflect the vehicle-track systematicness is constituted. It provides a reference for the further research of the dynamic analysis of vehicle-tunnel coupled system.

Calculation of Lumped Parameter of Two-Port Network for Volume Conduction Energy Delivery

2013 ◽  
Vol 680 ◽  
pp. 649-655
Author(s):  
Zhi De Tang ◽  
Xiu Fa Chen
Keyword(s):  
Coupling Model ◽  
Variable Load ◽  
Volume Conduction ◽  
Calculation Methods ◽  
Skin Electrode ◽  
Energy Delivery ◽  
Lumped Parameter ◽  
Equivalent Impedance ◽  
Impedance Parameters ◽  
Implanted Device

Skin electrode unit is the channel through which energy can be transferred to the implanted device by volume conduction. The unit can be equivalent to lumped circuit, but so far there are no appropriate calculation methods of these circuit parameters. In this paper, the field- circuit coupling model of skin electrode unit is established to compute the voltages and currents at electrode ports, then their amplitudes and phases are extracted by using all phase FFT spectrum analysis, at last the equivalent impedance parameters of the skin electrode unit are calculated by the application of variable load method. These impedance parameters can be used for optimizing the volume conduction energy delivery system.

scholarly journals Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1055
Author(s):  
Min Wang ◽  
Qifeng Guo ◽  
Pengfei Shan ◽  
Yakun Tian ◽  
Bing Dai
Keyword(s):  
Fluid Flow ◽  
Normal Stress ◽  
Contact Area ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Nonlinear Coefficient ◽  
Flow Characteristics ◽  
Shear Displacement ◽  
Navier Stokes Equation ◽  
Linear Coefficient

The hydraulic properties of fractures are greatly affected by the stress. Knowing the fluid flow behavior of fractures is of great importance to underground engineering construction and environmental safety. The main purpose of this paper is to study the fluid flow characteristics of rough fractures under different stress states. First, rough fracture surfaces were generated by using the corrected successive random addition (SRA) algorithm. Then, the sheared fracture models subjected to different stress condition were obtained under the boundary condition of constant normal stiffness (CNS). Finally, the hydraulic characteristics of the three-dimensional rough rock fractures were analyzed by numerically solving the full Navier–Stokes equation. It has been found that (1) the aperture of fractures all obeys the Gaussian distribution. The dilatancy effect is gradually obvious and aperture becomes larger with the increase of shear displacement. (2) When the initial normal stress increases, the contact area of fracture becomes larger and the reverse flow can be observed around the contact area. (3) The relationship between hydraulic gradient and flowrate exhibits nonlinearity which can be described by the Forchheimer’s law. The linear coefficient a and the nonlinear coefficient b gradually decrease with the increase of shear displacement and finally stabilize. The values of a and b are reduced by 1–2 and 1–3 orders of magnitude respectively during the shear. The critical Reynolds number increases with the increase of shear displacement and decrease as the initial normal stress increases.

Dynamic response and parameter analysis on the vehicle–bridge coupling of cable-stayed bridge under over-limit transportation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yao Lu ◽  
Dejian Li ◽  
Kai Wang ◽  
Zhen Li
Keyword(s):  
Dynamic Response ◽  
Limit Load ◽  
Simulation Method ◽  
Coupling Model ◽  
Parameter Analysis ◽  
Coupling Vibration ◽  
Distribution Width ◽  
Content Type ◽  
Finite Element Software ◽  
Cable Stayed Bridge

PurposeOver-limit transportation has the characteristics of large axle load, large number of axles and lateral distribution width. Under the action of over-limit load, the coupling vibration effect of vehicle–bridge is more obvious, and the deformation of bridge components is large. Thus, research and analysis of the vehicle–bridge coupling dynamic response of long-span bridges under over-limit transportation has practical engineering significance.Design/methodology/approachBased on the principle of invariable elastic potential energy, this paper derives dynamic model of over-limit transportation n-axis flat vehicle. The numerical simulation method is used to model and calculate a cable-stayed bridge, and the static effect of the cable-stayed bridge and the dynamic response of vehicle–bridge coupling under different parameters are compared and analyzed.FindingsThe focus is on the influence of vehicle load and vehicle velocity parameters on the stress and amplitude of different cables under over-limit transportation, and the corresponding variation law is obtained.Originality/valueThe research on the coupled dynamic response of cable-stayed bridges has attracted the attention of many scholars, but there are relatively few studies on the coupled vibration of out-limit vehicles and bridges. In this paper, based on finite element software, a vehicle–bridge coupling model under bulk transportation is established.

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