Vibration of an Elastic Beam Subjected to Discrete Moving Loads

1978 ◽  
Vol 100 (3) ◽  
pp. 514-519 ◽  
Author(s):  
M. Kurihara ◽  
T. Shimogo
Keyword(s):  
Spectral Density ◽  
Poisson Process ◽  
Time History ◽  
Elastic Beam ◽  
Moving Loads ◽  
Simply Supported ◽  
Power Spectral ◽  
Vibration Problems ◽  
Load Sequence ◽  
Input Load

In this paper, vibration problems of a simply-supported elastic beam subjected to randomly spaced moving loads with a uniform speed are treated under the assumption that the input load sequence is a Poisson process. In the case in which the inertial effect of moving loads is neglected, the time history, the power spectral density, and the various moments of the response are examined and the effects of the speed of moving loads upon the beam are made clear.

Stability of a Simply-Supported Beam Subjected to Randomly Spaced Moving Loads

1978 ◽  
Vol 100 (3) ◽  
pp. 507-513 ◽  
Author(s):  
M. Kurihara ◽  
T. Shimogo
Keyword(s):  
Elastic Beam ◽  
Inertia Force ◽  
Moving Loads ◽  
Simply Supported ◽  
Stability Chart ◽  
Vibration Problems ◽  
Load Sequence ◽  
Analytical Result ◽  
The Stability ◽  
Input Load

In this paper, vibration problems of a simply-supported elastic beam subjected to randomly spaced moving loads with a uniform speed are treated under the assumption that the input load sequence is a Poisson process. In the case in which the inertial effect of moving loads is taken into account, the stability problem relating to the speed and the mass of loads is dealt with, considering the inertia force, the centrifugal force, and the Coriolis force of the moving loads. As an analytical result a stability chart of the mean-squared deflection was obtained for the moving speed and the moving masses.

An Intermittent Poisson Process Generating 1/f Noise with Possible Application to Fluorescence Intermittency

2014 ◽  
Vol 13 (02) ◽  
pp. 1450015 ◽  
Author(s):  
Ferdinand Grüneis
Keyword(s):  
Power Spectrum ◽  
Spectral Density ◽  
Poisson Process ◽  
Power Spectral Density ◽  
High Frequency ◽  
Frequency Region ◽  
Excess Noise ◽  
State Process ◽  
Power Spectral ◽  
Fluorescence Intermittency

Quantum dots (QD) and other nanoparticles exhibit fluorescence intermittency switching irregularly between bright ("on") and dark ("off") states. On- and off-times follow a power-law statistics with exponents ranging from -1 to -2. The empirical power spectral density of this two-state process shows a 1/fx shape with an exponent x reverting from ≈1 at low frequencies to ≈2 at high frequency. Based on theoretical considerations, the low frequency region can be attributed to the on-state; however, there are some discrepancies in attributing the off-states to the high frequency region. This difficulty can be overcome by introducing a Poisson process which is gated by the two-state process giving rise to an intermittent Poisson process (IPP); in this way, the statistical features of the two-state process are transferred to the IPP. The power spectral density of the IPP can be derived in closed form for arbitrarily distributed on/off-states. Besides shot noise the power spectrum of the IPP exhibits excess noise with two scaling regions which can be attributed to the respective on/off-states. The results are applied to interpret the power spectrum of fluorescence intermittency in QDs.

SPECTRAL FEATURES OF THE ALTERNATING CLUSTER PROCESS

2010 ◽  
Vol 09 (03) ◽  
pp. 301-312
Author(s):  
FERDINAND GRÜNEIS
Keyword(s):  
Spectral Density ◽  
Poisson Process ◽  
Power Spectral Density ◽  
Random Noise ◽  
Excess Noise ◽  
Spectral Features ◽  
Cluster Process ◽  
State Process ◽  
Power Spectral ◽  
The Impact

The alternating cluster process is a Poisson process the rate of which is modulated by an underlying two-state process. We derive the power spectral density of the alternating cluster process; besides random noise we obtain excess noise due to the impact of modulation.

scholarly journals Power Spectral Density Response of Bridge-Like Structures Loaded by Stochastic Moving Forces

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Silvio Sorrentino
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Spectral Density Function ◽  
Mean Value ◽  
Moving Loads ◽  
Mean Values ◽  
Power Spectral ◽  
Potential Applications ◽  
Spectral Density Functions ◽  
The Mean

In this study, simple and manageable closed form expressions are obtained for the mean value, the spectral density function, and the standard deviation of the deflection induced by stochastic moving loads on bridge-like structures. As a basic case, a simply supported beam is considered, loaded by a sequence of concentrated forces moving in the same direction, with random instants of arrival, constant random crossing speeds, and constant random amplitudes. The loads are described by three stochastic processes, representing an idealization of vehicular traffic on a bridge in case of negligible inertial coupling effects between moving masses and structure. System’s responses are analytically determined in terms of mean values and power spectral density functions, yielding standard deviations, with the possibility to easily extend the results to more refined models of single span bridge-like structures. Potential applications regard structural analysis, vibration control, and condition monitoring of traffic excited bridges.

Analysis on Random Response of a Simply Supported Beam Subjected to Distributed Load

2014 ◽  
Vol 518 ◽  
pp. 120-125 ◽  
Author(s):  
Xiao Jing Li
Keyword(s):  
Spectral Density ◽  
Density Function ◽  
Power Spectral Density ◽  
Random Vibration ◽  
Spectral Density Function ◽  
Random Response ◽  
Power Spectral Density Function ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Power Spectral

The random vibration of simply-supported beam is simplified of the random vibration of the SDOF theory ,the paper analyse its random response. We get the displacement power spectral density function the velocity power spectral density and the acceleration power spectral density function of the maximum displacement point. The same example is calculated by ANSYS, it also get the same results.It proved that using the finite element analysis software ANSYS to anlaysis the random vibration of the simply-supported beam has advantages of fast speedhigh precisioneasy stepsthe small error and so on..

Calculation of Evolutionary Power Spectral Density of Bridge Response to Earthquakes by Convolution Summation

2019 ◽  
Vol 19 (04) ◽  
pp. 1950041
Author(s):  
Xianting Du ◽  
Hong Qiao ◽  
Chaoyi Xia ◽  
He Xia
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Degrees Of Freedom ◽  
Computational Cost ◽  
Time History ◽  
Dynamic Component ◽  
Rigid Frame ◽  
Power Spectral ◽  
History Analysis ◽  
Constant Coefficients

This paper presents a method for calculating the evolutionary power spectral density (EPSD) of the seismic response of bridges using the convolution summation. With zero initial values, a formula for the dynamic component of the response of bridges to spatially varying seismic ground motions is derived as the convolution summation, by assuming the seismic acceleration to vary linearly between two adjacent time stations. The convolution summation is used for calculating the convolution integral of the dynamic component response factor in the EPSD, in which the constant coefficients are independent of the harmonically modulated excitation. The constant coefficients are obtained by the time-history analysis using triangular unit impulse acceleration excitations. The computational cost of the EPSD depends mainly on the amount of degrees-of-freedom (DOFs) numbers of bridge supports in contact. The corresponding computational scheme is proposed, and its validity is indirectly verified with a single DOF system, by comparing the results obtained with those of the existing methods. Finally, a three-span continuous rigid-frame bridge is taken as a case study to illustrate the applicability and effectiveness of the proposed scheme.

Fuzzy Modeling of Multi-Degree-of-Freedom Power Spectral Density Systems

2009 ◽  
Vol 2 (1) ◽  
pp. 40-47
Author(s):  
Montasser Tahat ◽  
Hussien Al-Wedyan ◽  
Kudret Demirli ◽  
Saad Mutasher
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Fuzzy Modeling ◽  
Degree Of Freedom ◽  
Power Spectral
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