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This work highlights the significant variation of the natural frequencies of the segmented wind turbine blade by the assembling load of the segments versus blade rotating speed. ... In this paper, numerical and experimental modal analysis of a segmented wind turbine blade assembled with a steel threaded shaft and a nut are presented. ... The results show the increase of the blade natural frequencies of all modes due to increasing tightening torque applied by the nut to assemble the blade segments, in addition to an increase in the rotational ...doi:10.15632/jtam-pl.57.1.85 fatcat:uiplp57cufgdhadaw4ou5s6rda
The results of the modal analysis of the stationary rotor blade were compared with the results obtained by the bump test, which confirmed the numerical model of the blade. ... A modal analysis of a rotating rotor blade was performed on the same numerical model, and Campbell diagrams were plotted to determine the critical speed ... When the frequency of the excitation force coincides with the natural frequency of the rotor blades, resonance occurs, which is manifested by an increase in the amplitude of vibrations and consequently ...doi:10.31803/tg-20210302210045 fatcat:cp7kxslwifhvtkkmjlta2oqr5e
Naval Engineers Journal
In these methods the blade receives an impulsive force each time it passes the magnet, or air jet, and determination of any but the lowest mode of vibration is extremely difficult. ... TURBINE BLADE VIBRATION “ENGINEERING” frequency of the principal exciting forces and also those of the natural modes of vibration of the blades. ...
As the largest load, according to MIL-STD-810D, we considered a short-term impulse in the radial and axial direction with a magnitude of 50 g (force amplitude 25 kN). ... INTRODUCTION Demands for increased power of the main (internal combustion) engine in combat vehicles require cooling systems with an increased heat dissipation capability. ...doi:10.20855/ijav.2002.7.3117 fatcat:tdz3uyah4bgu7caajwnt7nhjgi
Naval Engineers Journal
It was shown that free blades could be excited by the smallest impulses even if the frequency of the exciting impulses was only a fraction of frequency of free vibration. ... These experiments were mede as those previously described by directing a stream of compressed air against the blading which stream was interrupted by a rotating disc with a hole, the speed of which could ...
The article present an overview of the infrared measurement techniques and algorithms proposed research design based on the selected infrared measurement techniques. ... In particular it focuses on the analysis of the possibility of studying the dynamics of the rotor and the detection of its failures during operation. ... OPTICAL EXCITED THERMOGRAPHY Thermography with optical excitation is a method of dynamic measurements based on measurement with an external excitation, the source of which is thermal radiation The forcing ...doi:10.24136/jaeee.2021.001 fatcat:5bwg7nxhnbcb7bg2vl3ndbjege
The low-frequency in-plane thickness noise generating from the displacement of air by rotating blades has an important influence on helicopter detection. ... Following the theoretical study on the mechanism of thickness noise reduction using in-plane unsteady force, a 2-m diameter rotor with an active trailing-edge winglet are designed and tested in a fully ... Conflicts of Interest: The authors declare no conflict of interest. Appl. Sci. 2019, 9, 1351 ...doi:10.3390/app9071351 fatcat:jmdq5fkg4vd2hbptynsqciuv3i
An efficient multiharmonic balance method is proposed in order to compute the forced response of bladed disks with contact and friction nonlinearities in blade roots. ... For experimental validation purposes, a rotating bladed disk was tested in a vacuum chamber, with excitation being provided by piezoelectric actuators. ... An example of frequency responses for blades 1 and 2, to an excitation on blade 2, is shown in Figure 4 for a given excitation level of 80 Volts and for a 3000 rpm rotating speed. ...doi:10.1155/ijrm/2006/71302 fatcat:guefhsiocfb5piafw4opa2qw5y
The measurement response for the impulse excitation of the ball shooter device is compared to the results of impulse modal tests performed with a micro hammer. ... We propose an online measurement method with an automatic ball shooter device which can excite a wide frequency range of the flexible workpiece. ... Conflicts of Interest: The authors declare no conflict of interest. ...doi:10.3390/jmmp4030078 fatcat:s42pzvmd75b33lx6ywttj2wq4e
when the negative allowance on the bearing bushing disappears, excitation of blade harmonics, etc.) are described in brief. ... Blade frequencies of the compressor and turbines on turbochargers with cylindrical and elliptical sliding bearings have been found in the high-frequency part of the vibration spectrum. ... , which causes an increase in centrifugal forces  . ...doi:10.14419/ijet.v7i4.3.19556 fatcat:felvnngumrd7fmymqzaxdh4q4m
An advanced instrument set is used to monitor both vibrating structures and the surrounding flow. The paper highlights the interaction between vibrating guide vanes and the flow behavior. ... The pressure fluctuations in the stay vanes region are found to be strongly influenced by the amplitude of the vibrating guide vanes. ... Acknowledgments The present investigation was carried out in the frame of HYDRODYNA II project (Eureka N° 4150), in a partnership with ALSTOM Hydro, ANDRITZ Hydro, VOITH Hydro and UPC-CDIF. ...doi:10.1088/1755-1315/12/1/012074 fatcat:au4zucdjrzeojjkovqfarepzgy
Blade vibration has to be considered in the design of high pressure ratio / high mass flow centrifugal compressors with increasing rotational speed values due to the reduced blade thickness. ... Results of blade vibration measurements on compressors with a vaneless diffuser carried out with semiconductor strain gages and an 8-channel telemetry system are presented for constant rotational speed ... Results in figure 15 show increasing intensity of blade excitation towards higher values of rotational speed due to the effect of increasing forces in the flow. ...doi:10.1515/tjj.1987.4.1-2.107 fatcat:frzsn4t7hjahfdtbez2wa5kh7u
The varied parameters are the ratio of x-axis distance of blade profile with the aid of chord length and ratio of maximum peak of blade profile in y-path to the chord period. ... The steam turbine offers the better thermodynamic performance with the aid of the usage of a couple of levels inside the growth of steam. ... Ultimate level of steam turbine impulse-response blades are very lots immediately have an effect on performance of plant. ...doi:10.22214/ijraset.2021.37806 fatcat:jtpegamqd5ee7oitvn23uhhcta
Through the application of the VES an aimed vibration excitation is realised in a co-rotating coordinate system, which enables a non-invasive and precise modal analysis of rotating components. ... A vibration excitation system (VES) in a form of an active coupling is proposed, designed and manufactured. ... Therefore, the VES was mounted onto a vibration isolated table and excited using an impactor with integrated force sensor, that delivered the reference of the excitation signal. ...doi:10.3390/s19010092 fatcat:foci52fv7zfzlpsvtxlkst6gtu
The method is demonstrated by considering the first two bending modes with an inter-blade phase angle (IBPA) of 0° on a transonic compressor. ... A novel method has been developed to predict aerodynamic damping by employing two single time-domain simulations, specifically, one with the blade impulsed naturally in a vacuum and one with the blade ... Conflicts of Interest: The authors declare no conflict of interest. Appl. Sci. 2019, 9, 4411 ...doi:10.3390/app9204411 fatcat:ohzwqm44yjbepjp2zompw5mxg4
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