The relationship between structural vibration and noise of railway vehicles

2012 ◽  
Vol 131 (4) ◽  
pp. 3264-3264 ◽  
Author(s):  
Gong Lv ◽  
Junhai Liang ◽  
Jinzhu Liu ◽  
Jianmin Ge
Keyword(s):  
Structural Vibration ◽  
Railway Vehicles ◽  
The Relationship

scholarly journals Active control of structures and sound radiation modes and its application in vehicles

2016 ◽  
Vol 35 (4) ◽  
pp. 291-302 ◽  
Author(s):  
He-Xuan Hu ◽  
Bo Tang ◽  
Yang Zhao
Keyword(s):  
Radiation Power ◽  
Low Frequency ◽  
Sound Radiation ◽  
Diagonal Element ◽  
Structural Vibration ◽  
Structural Dynamic ◽  
First Order ◽  
Sound Radiation Efficiency ◽  
Sound Radiation Power ◽  
The Relationship

This paper presents computation of structural sound power and sound radiation modes, combined with structural dynamic equations to obtain the coupling relationship between sound and structures. As a result, the relationship between sound radiation modes of structures and structural vibration modes is established. The influence of the number and position of optimal secondary force sources on control of sound radiation modes is considered. Results show that sound radiation efficiency of sound radiation modes at the first order was more than that of sound radiation modes at other orders. The main diagonal element of coupling matrix between modes and sound radiation impedances was more than elements at other positions. Sound radiation modes at the first order were dominant sound radiation modes. When the number of secondary force sources was 4, the sound radiation power of structures was the lowest. Four force sources were taken as the basis to conduct on the related experiments in the anechoic chamber and compare with the computational result. Their results had a good consistency, which showed that the mentioned theory method was effective. Finally, the control strategy was applied to roofs of the vehicle. Experiments verified that sound pressure level of the driver in the low frequency was obviously improved, which remedied the defect of other optimization strategies for solving noises in the low frequency.

Thickness Optimization Study of Constrained Damping Plate

2012 ◽  
Vol 226-228 ◽  
pp. 436-439
Author(s):  
Hao Chuan Wan ◽  
Ling Zheng ◽  
Yi Nong Li
Keyword(s):  
Natural Frequency ◽  
Loss Factor ◽  
Added Mass ◽  
Structural Vibration ◽  
Viscoelastic Layer ◽  
Thickness Optimization ◽  
Damping Effect ◽  
Optimization Study ◽  
Constrained Damping ◽  
The Relationship

Based on Kirchhoff hypothesis, the vibration equations of constrained damping plate are established and the equations are solved. Influence of the thicknesses of constrained layer and viscoelastic layer on structural vibration character are analyzed, the curves of natural frequency and loss factor with different thicknesses of viscoelastic layer and constrained layer are obtained. The figures indicated that it is not the more thickness of the viscoelastic layer and constrained layer the higher of the loss factor. Both of the thicknesses have optimum values, which are interact. The relationship between of loss factor and added mass is investigated. The results show that various thickness plans can obtain the same loss factor but very different added mass. So it is very necessary to optimize the thickness of viscoelastic layer and constrained layer to obtain the best damping effect.

scholarly journals Influence of Bending Vibration on the Vertical Vibration Behaviour of Railway Vehicles Carbody

2021 ◽  
Vol 11 (18) ◽  
pp. 8502
Author(s):  
Mădălina Dumitriu ◽  
Ioana Izabela Dihoru
Keyword(s):  
Ride Comfort ◽  
Reference Points ◽  
Structural Vibration ◽  
Railway Vehicle ◽  
Type Model ◽  
Vertical Acceleration ◽  
Bending Vibration ◽  
Railway Vehicles ◽  
Bending Mode ◽  
Vertical Vibrations

The topic of reducing structural vibrations in the case of flexible carbodies of railway vehicles has been intensively studied, but it is still an active research topic thanks to the importance of the perspective of improving the ride comfort. However, no study has been identified in the specialty literature to feature the contribution of the vibration structural modes upon the vibration behaviour of the railway vehicle carbody. The structural vibration modes of the flexible carbodies are particularly complex; however, the first vertical bending mode holds great significance in terms of the ride comfort. This paper analyses the influence of the first vertical bending mode on the vibration behaviour in three reference points of the railway vehicle carbody in correlation with the carbody flexibility, the vehicle velocity and the suspension damping. This study relies on comparisons between the results of the numerical simulations obtained for a ‘flexible carbody’ type model of the vehicle and the ones obtained for a ‘rigid carbody’ type model. The first part of this study analyses the characteristics of the vertical vibrations behaviour of the flexible carbody based on the dynamic response of the vehicle and expressed as the acceleration power spectral density. In the second part, the influence of the vertical bending on the vertical vibrations level of the carbody is analysed using the root mean square of the vertical acceleration.

scholarly journals Approaches for reducing structural vibration of the carbody railway vehicles

2017 ◽  
Vol 112 ◽  
pp. 07006
Author(s):  
Mădălina Dumitriu ◽  
Cătălin Cruceanu
Keyword(s):  
Structural Vibration ◽  
Railway Vehicles

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Tinkering with cognitive gadgets: Cultural evolutionary psychology meets active inference

2019 ◽  
Vol 42 ◽  
Author(s):  
Paul Benjamin Badcock ◽  
Axel Constant ◽  
Maxwell James Désormeau Ramstead
Keyword(s):  
Evolutionary Psychology ◽  
Research Program ◽  
Active Inference ◽  
Innovative Research ◽  
Cognitive Faculties ◽  
Cultural Evolutionary ◽  
The Relationship

Abstract Cognitive Gadgets offers a new, convincing perspective on the origins of our distinctive cognitive faculties, coupled with a clear, innovative research program. Although we broadly endorse Heyes’ ideas, we raise some concerns about her characterisation of evolutionary psychology and the relationship between biology and culture, before discussing the potential fruits of examining cognitive gadgets through the lens of active inference.

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

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