scholarly journals THE INVESTIGATION OF VIBRO-ISOLATING FEATURES OF TRANSMISSIONS OF VEHICLES IN ELASTIC CENTRIFUGAL COUPLINGS USING THE METHOD OF IDENTIFICATION OF DYNAMIC PROCESSES IN HALF-COUPLINGS ON THE UNIVERSAL DYNAMIC TEST STAND

Transport ◽  
2002 ◽  
Vol 17 (3) ◽  
pp. 77-84
Author(s):  
Bronislovas Spruogis ◽  
Leonas Zubavičius
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Dynamic Test ◽  
Power Saving ◽  
Wide Frequency Range ◽  
Test Stand ◽  
Dynamic Processes ◽  
Frequency Range ◽  
Rotor Systems ◽  
Resonance Frequencies

The presented paper describes the investigation of vibro-isolating features of transmissions of vehicles using universal dynamic test stand. The stand is protected by copyright and distinguishes itself for many advantages in comparison with the existing stands: it is contactless, precise in a wide frequency range, power-saving, high-speed. Due to low exploitation expenses and wide possibilities it is fit for the investigation of dynamic characteristics of various vehicles. On the said stand using the method of the identification of experiment dynamic processes, the investigation of vibroisolating features of rotor systems has been performed. The errors caused by the unevenness of rotation of connecting shafts, the adequacy of the calculated models and the dangerous resonance frequencies have been determined.

VIBRATION-ISOLATING BALL-TYPE CLUTCH AS A SOURCE OF INCREASED VIBRATION ACTIVITY IN THE SYSTEM: AMORTIZED MECHANISM – SHAFT LINE

Akustika ◽  
2021 ◽  
pp. 177
Author(s):  
Irina Kudryavtseva ◽  
Sergey A. Rykov ◽  
Sergey V. Rykov
Keyword(s):  
Experimental Data ◽  
Experimental Studies ◽  
Wide Frequency Range ◽  
Test Stand ◽  
Frequency Range ◽  
Diagnostic Features ◽  
Shaft Line

The results of experimental studies of vibration activity of a vibration-insulating ball-type clutch installed on a shaft line are presented. These studies were made on the test stand. It is shown that, depending on the value of the shaft line fracture, the vibration activity of the ball-type clutch can increase in a wide frequency range up to 30 dB. The diagnostic features of the ball-type clutch which allow estimating its vibration activity have been identified on the basis of the analysis of experimental data.

Investigation of an OHC Valve Train With Respect to Sound Quality

1995 ◽  
Author(s):  
In-Soo Suh ◽  
Sophie Debost
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Transfer Functions ◽  
Sound Quality ◽  
Valve Train ◽  
Subjective Response ◽  
Frequency Range ◽  
Lumped Mass ◽  
Mass Model ◽  
Resonance Frequencies

Abstract Although the vibration generated by high speed dynamic movement of a valve train (VT) in an overhead camshaft SI engine is not a major source of engine noise, it still affects the overall sound quality of the engine, which is important to the subjective response of the customer. The purpose of this research is to determine the specific mechanism of the valve train dynamic behavior, which is responsible for noise generation, and the vibration transmission characteristic to engine surfaces. Dynamic simulation with a lumped mass model is developed to analyze the dynamic behavior of VT during operation, and reveal the resonance frequencies of VT modeshapes excited by the cam harmonics. Also, experimental measurements of the valve acceleration, transfer functions of vibration, and the structural response have been performed in the valve train rig. Based on the spectral analysis, two distinct noise generating mechanisms are determined. Vibration from VT components’ interaction, which is mainly excited by the harmonics of the cam profile during valve opening period, is dominant in the frequency range less than 6 kHz. On the other hand, valve seating is the dominant source in the frequency range from 6 kHz to 20 kHz. The more vibration energy from these two sources is transmitted through the structure via the VT system, rather than directly via the valve seat to the surfaces where sound is radiated, especially around the frequency of 5 kHz and 11 kHz. This fundamental investigation on the vibration sources and its transmission characteristics provides a new insight on the VT noise, which is an essential step toward the design of an engine with better sound quality.

scholarly journals A Tuned Mass Damper with Nonlinear Magnetic Force for Vibration Suppression with Wide Frequency Range of Offshore Platform under Earthquake Loads

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Qiong Wu ◽  
Wei Zhao ◽  
Weiguo Zhu ◽  
Rencheng Zheng ◽  
Xilu Zhao
Keyword(s):  
High Speed ◽  
Permanent Magnets ◽  
Vibration Suppression ◽  
Wide Frequency Range ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Frequency Range ◽  
Response Characteristics ◽  
Narrow Frequency Band ◽  
Dynamic Performances

Tuned mass dampers (TMDs) are applied to ensure the safety and stability of offshore platforms; however, linear dampers are effective for a single resonance frequency, providing vibration suppression only within a narrow frequency band. Therefore, this paper proposed a magnetic TMD with two pairs of permanent magnets on both sides of the structures, which can generate a nonlinearly repulsive force, making the magnetic TMD reliable and robust in damping the oscillations of structures with wide frequency range under seismic excitations. A comprehensively numerical and experimental study was processed to investigate the dynamic performances of the proposed magnetic TMD, by application of a 1 : 200-scale prototype of the offshore platform. The results verified that the performance of the magnetic TMD can be significantly improved than that of the linear TMD, meanwhile maintaining high-speed response characteristics. The experimental results indicated that the displacement, acceleration, and frequency responses of the offshore platform can be significantly reduced; furthermore, the evaluation indices showed that the magnetic TMD system is credible in reducing the overall vibration levels and maximum peak values.

On the Coupling of Foil Bearing Supported Rotors: Part 1 — Analysis

2007 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton ◽  
Crystal A. Heshmat
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Ball Bearing ◽  
Dynamic Performance ◽  
Rotor Systems ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Flexible Rotors ◽  
Coupling Dynamic ◽  
Bearing System

The expanded application of high-speed rotor systems operating on compliant foil bearings will be greatly enhanced with the ability to adequately couple multiple shaft systems with differing bearing systems and dynamic performance. In this paper the results of an analytical tradeoff study assessing coupling dynamic characteristics and their impact on coupled rotor-bearing system dynamics are presented. This analysis effort was completed in an effort to establish the form of characteristics needed to couple foil bearing supported rotors to ball bearing supported rotors, other foil bearing supported rotors as well as coupling rigid and flexible rotors both supported on foil bearings. The conclusions from this study indicate that with appropriate coupling design, a wide array of foil bearing supported rotor systems may be successfully coupled.

scholarly journals A Dual Resonance Electromagnetic Vibration Energy Harvester for Wide Harvested Frequency Range with Enhanced Output Power

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7675
Author(s):  
Zhijie Feng ◽  
Han Peng ◽  
Yong Chen
Keyword(s):  
Resonant Frequency ◽  
Power Density ◽  
Output Power ◽  
Energy Harvester ◽  
Relative Displacement ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Vibration Energy Harvester ◽  
Resonance Frequencies ◽  
Dual Resonance

A dual resonance vibration electromagnetic energy harvester (EMEH) is proposed in this paper to extend frequency range. Compared with the conventional dual resonance harvester, the proposed system realizes an enhanced “band-pass” harvesting characteristic by increasing the relative displacement between magnet and coil among two resonance frequencies with a significant improvement in the average harvested power. Furthermore, two resonant frequencies are decoupled in the proposed system, which leads to a more straightforward design. The proposed dual resonance EMEH is constructed with a tubular dual spring-mass structure. It is designed with a serpentine planar spring and the coil position is optimized for higher power density with an overall size of 53.9 cm3 for the dual resonance EMEH. It realizes an output power of 11 mW at the first resonant frequency of 58 Hz, 14.9 mW at the second resonant frequency of 74.5 Hz, and 0.52 mW at 65 Hz, which is in the middle of the two resonance frequencies. The frequency range of output power above 0.5 mW is from 55.8 Hz to 79.1 Hz. The maximum normalized power density (NPD) reaches up to 2.77 mW/(cm3·g2). Compared with a single resonance harvester design under the same topology and outer dimension at a resonant frequency of 74.5 Hz, the frequency range in the proposed EMEH achieves more than a 2× times extension. The proposed dual resonance EMEH also has more than 2 times wider frequency range than other state-of-art wideband EMEHs. Therefore, the proposed dual resonance EMEH is demonstrated in this paper for a high maximum NPD and higher NPD over a wide frequency range.

scholarly journals Features of designing line radio interference filter in a wide frequency range, taking into account equivalent circuits for capacitors and inductors

2021 ◽  
Vol 23 (4) ◽  
pp. 85-96
Author(s):  
Vladimir F. Dmitrikov ◽  
Alexander Yu. Petrochenko ◽  
Vyacheslav M. Isaev ◽  
Dmitriy V. Shushpanov
Keyword(s):  
Interference Filter ◽  
Wide Frequency Range ◽  
Dielectric Constants ◽  
Dynamic Processes ◽  
Complex Frequency ◽  
Radio Interference ◽  
Frequency Range ◽  
Electric Circuits ◽  
Parasitic Parameters ◽  
Frequency Properties

Based on the phenomenological equations describing the dynamic processes of magnetization of ferromagnets of inductors and polarization of capacitor dielectrics, taking into account complex frequency-dependent dielectric constants e(jw) of capacitor dielectrics and magnetic permeabilities m(jw) of inductor cores, equivalent electrical structural-parametric and capacitor replacement circuits were obtained. The connection of parasitic elements of equivalent electric circuits of capacitors and inductors with the electrophysical characteristics of the material of the dielectric of the capacitor and the inductor core, which determine their frequency properties, structure and parameters of the elements of the equivalent circuit, is established. The features of the design of line radio interference filter taking into account the parasitic parameters of the inductors and capacitors of line radio interference filter, found as a result of the synthesis of equivalent electric circuits of the inductors and capacitors in a wide frequency range of 150 kHz 30 MHz.

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