Steady-State Dynamic Response of a Kirchhoff’s Slab on Viscoelastic Kelvin’s Foundation to Moving Harmonic Loads

2007 ◽  
Vol 74 (6) ◽  
pp. 1212-1224 ◽  
Author(s):  
Lu Sun
Keyword(s):  
Dynamic Response ◽  
Material Properties ◽  
Critical Speed ◽  
Complex Analysis ◽  
The Other ◽  
Maximum Response ◽  
Damping Coefficient ◽  
Harmonic Load ◽  
Load Frequency ◽  
Moving Harmonic Load

In this paper, fast Fourier transform and complex analysis are used to analyze the dynamic response of slabs on a viscoelastic foundation caused by a moving harmonic load. Critical speed and resonance frequency of the slab to a moving harmonic load are obtained analytically. It is proved that there exists a bifurcation in critical speed. One branch of critical speed increases as load frequency increases, while the other branch of critical speed decreases as load frequency increases. There are two critical speeds when the load frequency is low, but only one critical speed exists when the load frequency is high. A parametric study is also performed to study the effect of load speed, load frequency, material properties of the slab and the damping coefficient on dynamic response. It is found that the damping coefficient has significant influence on dynamic response. For small damping, the maximum response of the slab increases with increased load speed and frequency. However, for large damping, the maximum response of the slab decreases with increased load speed and frequency.

scholarly journals Study on dynamic response of track structures under a variable speed moving harmonic load

2017 ◽  
Vol 14 ◽  
pp. 214-219
Author(s):  
Yan Qi Liu ◽  
Yan Zhang ◽  
Chun Fang Song ◽  
Long Long Xu
Keyword(s):  
Dynamic Response ◽  
Harmonic Load ◽  
Variable Speed ◽  
Moving Harmonic Load

scholarly journals Nonlinear Dynamic Response of an Axially Functionally Graded (AFG) Beam Resting on Nonlinear Elastic Foundation Subjected to Moving Load

2019 ◽  
Vol 8 (1) ◽  
pp. 250-260 ◽  
Author(s):  
Mehdi Alimoradzadeh ◽  
Mehdi Salehi ◽  
Sattar Mohammadi Esfarjani
Keyword(s):  
Differential Equations ◽  
Dynamic Response ◽  
Nonlinear Vibration ◽  
Natural Frequency ◽  
Nonlinear Dynamic ◽  
Vibration Analysis ◽  
Functionally Graded ◽  
Harmonic Load ◽  
Nonlinear Dynamic Response ◽  
Moving Harmonic Load

Abstract In recent years, structures made of Functionally Graded materials (FGMs) are used in industries due to the continuously compositional variation of the constituents in FGMs along different directions. In order to develop FGMs, nonlinear vibration analysis to study dynamic behavior is needed. This study proposes nonlinear vibration analysis of a simply supported axially functionally graded (AFG) beam subjected to a moving harmonic load as an Euler-Bernoulli beam utilizing Green’s strain tensor. Axial variation of material properties of the beam is based on the power law. The governing equations of motion are derived via Hamilton’s principle. The Galerkin’s method is implemented to reduce the nonlinear partial differential equations of the system to a number of nonlinear ordinary differential equations. He’s variational method is applied to obtain approximate analytical expressions for the nonlinear frequency and the nonlinear dynamic response of the AFG beam. The effect of some parameters such as the power index and stiffness coefficients, among others, on the nonlinear natural frequency has been investigated. The influence of above mentioned parameters as well as the velocity of the moving harmonic load on the nonlinear dynamic response has been studied. The results indicate that these parameters have a considerable effect on both nonlinear natural frequency and response amplitude.

Dynamic Response of Bridge Subjected to Moving Harmonic Load

2012 ◽  
Vol 178-181 ◽  
pp. 2019-2022
Author(s):  
Ke Li ◽  
Jing Ji
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Vibration Control ◽  
Vibration Analysis ◽  
Element Model ◽  
Harmonic Load ◽  
Moving Loads ◽  
Ansys Software ◽  
Moving Harmonic Load ◽  
Pass Through

On the basis of typical theory on vibration analysis of the bridge and vehicles, by using the ANSYS software, a finite element model of the bridge is established. The character on dynamic response of bridge is analyzed when harmonic Loads with different frequencies pass through the bridge, and inner-force of bridge is given. The research will give beneficial rules for the vibration control of bridge under moving loads.

scholarly journals Erratum: Study on dynamic response of track structures under a variable speed moving harmonic load

2017 ◽  
Vol 15 ◽  
pp. 165-165
Author(s):  
Yan Qi Liu ◽  
Yan Zhang ◽  
Chun Fang Song ◽  
Long Long Xu
Keyword(s):  
Dynamic Response ◽  
Harmonic Load ◽  
Variable Speed ◽  
Moving Harmonic Load

Formation of Standing Waves in Radial Tires

1984 ◽  
Vol 12 (1) ◽  
pp. 44-63 ◽  
Author(s):  
Y. D. Kwon ◽  
D. C. Prevorsek
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Unit Length ◽  
Standing Waves ◽  
Rolling Resistance ◽  
Damping Coefficient ◽  
Circular Membrane ◽  
Critical Speeds ◽  
Steel Cord ◽  
The Individual

Abstract Radial tires for automobiles were subjected to high speed rolling under load on a testing wheel to determine the critical speeds at which standing waves started to form. Tires of different makes had significantly different critical speeds. The damping coefficient and mass per unit length of the tire wall were measured and a correlation between these properties and the observed critical speed of standing wave formation was sought through use of a circular membrane model. As expected from the model, desirably high critical speed calls for a high damping coefficient and a low mass per unit length of the tire wall. The damping coefficient is particularly important. Surprisingly, those tire walls that were reinforced with steel cord had higher damping coefficients than did those reinforced with polymeric cord. Although the individual steel filaments are elastic, the interfilament friction is higher in the steel cords than in the polymeric cords. A steel-reinforced tire wall also has a higher density per unit length. The damping coefficient is directly related to the mechanical loss in cyclic deformation and, hence, to the rolling resistance of a tire. The study shows that, in principle, it is more difficult to design a tire that is both fuel-efficient and free from standing waves when steel cord is used than when polymeric cords are used.

Optimum Design of Journal Bearings Dimensions for Rotating Machines

2020 ◽  
Vol 38 (10A) ◽  
pp. 1481-1488
Author(s):  
Tariq M. Hammza ◽  
Ehab N. Abas ◽  
Nassear R. Hmoad
Keyword(s):  
Aspect Ratio ◽  
Dynamic Response ◽  
Numerical Solution ◽  
Critical Speed ◽  
Design Method ◽  
Considerable Effect ◽  
Journal Bearings ◽  
Rotating Machines ◽  
Bearing Clearance ◽  
Study Results

The values of Many parameters which involve in the design of fluid film journal bearings mainly depend on the bearing applied load when using the conventional design method to design the journal bearings, in this study, as well as applied bearing load, the dynamic response and critical speed have been used to calculate the dimensions of journal bearings. In the field of rotating machine, especially a heavy-duty rotating machines, the critical speed and response are the main parameters that specify bearing dimensions. The bearing aspect ratio (bearing length to bore diameter) and bearing clearance have been determined based on rotor maximum critical speed and minimum response displacement. The analytical solution of rotor Eq. of motion was verified by numerical solution via using ANSYS Mechanical APDL 18.0 and by comparing the numerical solution with the preceding study. The final study results clearly showed that the bearing aspect ratio has little effect on the critical speed, but it has a high effect on the dynamic response also the bearing clearance has little effect on the critical speed and considerable effect on the dynamic response. The study showed that the more accurate values of bearing aspect ratio to make the response of rotor as low as possible are about 0.65 - 1 and bearing percent clearance is about 0.15 - 0.2 for different rotor dimensions.

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