scholarly journals Influence of the rotation speed on the dynamic behaviour of a cracked rotating beam

2021 ◽  
pp. 103209
Author(s):  
B. Valverde-Marcos ◽  
B. Muñoz-Abella ◽  
P. Rubio ◽  
L. Rubio
Keyword(s):  
Dynamic Behaviour ◽  
Rotation Speed ◽  
Rotating Beam

scholarly journals Theoretical and Experimental Investigation of the Dynamic Behaviour of Centrifugal Fans

2000 ◽  
Vol 6 (3) ◽  
pp. 227-233 ◽  
Author(s):  
G. Mariaux ◽  
Y. Gervais ◽  
L. Crespeau
Keyword(s):  
Experimental Investigation ◽  
Theoretical Model ◽  
Flow Rate ◽  
Dynamic Behaviour ◽  
Rotation Speed ◽  
Experimental Measurements ◽  
Transient Behaviour ◽  
Centrifugal Fans

In this paper, a theoretical model is proposed to investigate the centrifugal fans' transient behaviour in response to sudden imposed changes in pressure or flow rate. We are especially interested in the dissipative or creative energy transient behaviour of the fans located in actual aeraulic networks.The model is based on the global modelisation of the motor and resistant torques (due to pressure and viscosity actions on the blades) which are present on the rotor and by their coupling with its inertia.The model is then validated by experimental measurements which show its validity. In the case of the tested fan, the instantaneous characteristics (in particular the flow rate and rotation speed) have been correctly predicted by the model, with regard to time as well as amplitudes, provided the flow is not reversed.

Rotation Effects on Vibration of Structures Seen From a Rotating Beam Simply Supported off the Rotation Axis

2005 ◽  
Vol 128 (3) ◽  
pp. 328-337 ◽  
Author(s):  
J. Kim
Keyword(s):  
Coriolis Force ◽  
Natural Frequencies ◽  
Rotation Speed ◽  
Rotation Axis ◽  
Slenderness Ratio ◽  
Rotating Beam ◽  
Simply Supported ◽  
Axis Of Rotation ◽  
Vibration Responses ◽  
Practical Implications

In rotating beams, the Coriolis force acts through the mass and rotary inertias of the beam. A rotating beam simply supported off the axis of rotation is used as an example to study effects of this Coriolis force on vibration of structures. By adopting such a simple model, mass- and rotary inertia-induced terms in the free vibration responses can be obtained in separate, closed forms. The effect of each of these terms on vibration characteristics of the rotating beam is discussed in relation to parameters such as nonrotating natural frequencies, the rotation speed, and the slenderness ratio. Practical implications of these results in analyses of rotating structures of other types are discussed, for example estimating the significance of rotary inertias in relation to the slenderness ratio and the rotation speed.

Determination of Isospectral Nonuniform Rotating Beams

2012 ◽  
Vol 79 (6) ◽  
Author(s):  
Sandilya Kambampati ◽  
Ranjan Ganguli ◽  
V. Mani
Keyword(s):  
Natural Frequencies ◽  
Rotation Speed ◽  
Rectangular Cross Section ◽  
Rotating Beam ◽  
Element Analysis ◽  
Rotating Beams ◽  
Type Transformation ◽  
The Given ◽  
Nonuniform Beam

In this paper we look for nonuniform rotating beams that are isospectral to a given uniform nonrotating beam. A rotating nonuniform beam is isospectral to the given uniform nonrotating beam if both the beams have the same spectral properties, i.e., both the beams have the same set of natural frequencies under a given boundary condition. The Barcilon-Gottlieb type transformation is proposed that converts the governing equation of a rotating beam to that of a uniform nonrotating beam. We show that there exist rotating beams isospectral to a given uniform nonrotating beam under some special conditions. The boundary conditions we consider are clamped-free and hinged-free with an elastic hinge spring. An upper bound on the rotation speed for which isospectral beams exist is proposed. The mass and stiffness distributions for these nonuniform rotating beams which are isospectral to the given uniform nonrotating beam are obtained. We use these mass and stiffness distributions in a finite element analysis to show that the obtained beams are isospectral to the given uniform nonrotating beam. A numerical example of a beam having a rectangular cross section is presented to show the application of our analysis.

Investigation of fused silica dynamic behaviour

2006 ◽  
Vol 134 ◽  
pp. 929-934 ◽  
Author(s):  
F. Malaise ◽  
J.-M. Chevalier ◽  
I. Bertron ◽  
F. Malka
Keyword(s):  
Dynamic Behaviour ◽  
Fused Silica

A MODEL FOR THE FATIGUE SATURATION RANGE OF ALUMINIUM FROM DYNAMIC BEHAVIOUR AND INTERACTIONS OF DISLOCATIONS

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-155-C8-160
Author(s):  
R. FOUGERES ◽  
J. CHICOIS ◽  
A. HAMEL ◽  
A. VINCENT
Keyword(s):  
Dynamic Behaviour

Analysis of the Multi-Channel Epileptiform EEG Using the Markov Chains Formalism

1989 ◽  
Vol 28 (03) ◽  
pp. 160-167 ◽  
Author(s):  
P. Penczek ◽  
W. Grochulski
Keyword(s):  
Dynamic Behaviour ◽  
Joint Probability ◽  
Drug Effects ◽  
Anticonvulsant Drug ◽  
Channel System ◽  
Markov Network ◽  
Eeg Data ◽  
Multi Level ◽  
Joint Probability Functions ◽  
Dependent State

Abstract:A multi-level scheme of syntactic reduction of the epileptiform EEG data is briefly discussed and the possibilities it opens up in describing the dynamic behaviour of a multi-channel system are indicated. A new algorithm for the inference of a Markov network from finite sets of sample symbol strings is introduced. Formulae for the time-dependent state occupation probabilities, as well as joint probability functions for pairs of channels, are given. An exemplary case of analysis in these terms, taken from an investigation of anticonvulsant drug effects on EEG seizure patterns, is presented.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

An appraisal of characteristic mechanical properties and microstructure of friction stir welding for Aluminium 6061 alloy – Silicon Carbide (SiCp) metal matrix composite

2019 ◽  
Vol 13 (4) ◽  
pp. 5804-5817
Author(s):  
Ibrahim Sabry
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Welded Joint ◽  
Rotation Speed ◽  
Fusion Welding ◽  
Friction Stir ◽  
Al 6061

It is expected that the demand for Metal Matrix Composite (MMCs) will increase in these applications in the aerospace and automotive industries sectors, strengthened AMC has different advantages over monolithic aluminium alloy as it has characteristics between matrix metal and reinforcement particles.  However, adequate joining technique, which is important for structural materials, has not been established for (MMCs) yet. Conventional fusion welding is difficult because of the irregular redistribution or reinforcement particles.  Also, the reaction between reinforcement particles and aluminium matrix as weld defects such as porosity in the fusion zone make fusion welding more difficult. The aim of this work was to show friction stir welding (FSW) feasibility for entering Al 6061/5 to Al 6061/18 wt. % SiCp composites has been produced by using stir casting technique. SiCp is added as reinforcement in to Aluminium alloy (Al 6061) for preparing metal matrix composite. This method is less expensive and very effective. Different rotational speeds,1000 and 1800 rpm and traverse speed 10 mm \ min was examined. Specimen composite plates having thick 10 mm were FS welded successfully. A high-speed steel (HSS) cylindrical instrument with conical pin form was used for FSW. The outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt. %) was 195 MPa at rotation speed 1800 rpm, the outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt.%) was 165 MPa at rotation speed 1000 rpm, that was very near to the composite matrix as-cast strength. The research of microstructure showed the reason for increased joint strength and microhardness. The microstructural study showed the reason (4 %) for higher joint strength and microhardness.  due to Significant   of SiCp close to the boundary of the dynamically recrystallized and thermo mechanically affected zone (TMAZ) was observed through rotation speed 1800 rpm. The friction stir welded ultimate tensile strength Decreases as the volume fraction increases of SiCp (18 wt.%).

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