scholarly journals An Experimental Approach on Beating in Vibration Due to Rotational Unbalance

2020 ◽  
Vol 10 (19) ◽  
pp. 6899
Author(s):  
Dragos-Florin Chitariu ◽  
Florin Negoescu ◽  
Mihaita Horodinca ◽  
Catalin-Gabriel Dumitras ◽  
Gures Dogan ◽  
...  
Keyword(s):  
Vibration Sensor ◽  
Vibration Velocity ◽  
Periodic Pattern ◽  
Computer Assisted ◽  
Frequency Range ◽  
Combination Frequency ◽  
Dynamic Amplification Factor ◽  
Vibration Displacement ◽  
Velocity Signal ◽  
Displacement Signal

This paper proposes a study in theoretical and experimental terms focused on the vibration beating phenomenon produced in particular circumstances: the addition of vibrations generated by two rotating unbalanced shafts placed inside a lathe headstock, with a flat friction belt transmission between the shafts. The study was done on a simple computer-assisted experimental setup for absolute vibration velocity signal acquisition, signal processing and simulation. The input signal is generated by a horizontal geophone as the sensor, placed on a headstock. By numerical integration (using an original antiderivative calculus and signal correction method) a vibration velocity signal was converted into a vibration displacement signal. In this way, an absolute velocity vibration sensor was transformed into an absolute displacement vibration sensor. An important accomplishment in the evolution of the resultant vibration frequency (or combination frequency as well) of the beating vibration displacement signal was revealed by numerical simulation, which was fully confirmed by experiments. In opposition to some previously reported research results, it was discovered that the combination frequency is slightly variable (tens of millihertz variation over the full frequency range) and it has a periodic pattern. This pattern has negative or positive peaks (depending on the relationship of amplitudes and frequencies of vibrations involved in the beating) placed systematically in the nodes of the beating phenomena. Some other achievements on issues involved in the beating phenomenon description were also accomplished. A study on a simulated signal proves the high theoretical accuracy of the method used for combination frequency measurement, with less than 3 microhertz full frequency range error. Furthermore, a study on the experimental determination of the dynamic amplification factor of the combination vibration (5.824) due to the resonant behaviour of the headstock and lathe on its foundation was performed, based on computer-aided analysis (curve fitting) of the free damped response. These achievements ensure a better approach on vibration beating phenomenon and dynamic balancing conditions and requirements.

scholarly journals Analyzing vibration parameters of a modern high-speed engine during operation

2021 ◽  
Vol 2061 (1) ◽  
pp. 012056
Author(s):  
V V Gerasidi ◽  
A V Lisachenko
Keyword(s):  
Experimental Research ◽  
High Speed ◽  
Vibration Velocity ◽  
Frequency Range ◽  
Vibration Acceleration ◽  
Vibration Displacement ◽  
Black Sea Region ◽  
High Speed Engine ◽  
Vibration Parameters ◽  
Speed Engine

Abstract The paper presents results of experimental research into vibration parameters of a modern electronic control-enabled main high-speed engine, Caterpillar CAT 3516B as obtained during a running trial of a sea tug. CAT 3500 series Caterpillar high-speed engines are extensively used in sea tugs; there are about 40 units installed in vessels operating in the Azov and Black Sea region. The research technique involved measurement of vibration displacement, vibration velocity, vibration acceleration at an engine and its turbocharger components. The conducted experimental research has shown that in order to evaluate the technical state of an engine, it is necessary to measure vibration displacement and vibration velocity in a frequency range from 1 to 1000 Hz at 0.1 Hz intervals. For turbochargers, the vibration acceleration shall be measured in a frequency range from 1 to 15000 Hz at 1 Hz intervals. The results of the experimental research allowed determining necessary conditions for measurement of vibration parameters of Caterpillar CAT-3500 series modern high-speed engines commonly used in sea tugs. The experimental research into vessel installations by in-place diagnostics at operating sea-going vessels forms a foundation of an autonomous ship control system.

Fabrication and finite element analysis of vibrating parallel film actuator made with cellulose acetate for potential haptic application

2016 ◽  
Vol 230 (15) ◽  
pp. 2720-2727 ◽  
Author(s):  
Md Mohiuddin ◽  
Asma Akther ◽  
Eun Byul Jo ◽  
Hyun Chan Kim ◽  
Jaehwan Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cellulose Acetate ◽  
Vibration Characteristics ◽  
Experimental Results ◽  
Vibration Velocity ◽  
Frequency Range ◽  
Actuation Frequency ◽  
Element Analysis ◽  
Wide Range

The present study investigates a film actuator made with dielectric cellulose acetate films separated by narrow spacers as a means of electrostatic actuation for potential haptic application. Fabrication process for the actuator is explained along with experiments conducted over a wide frequency range of actuation frequency. A valid finite element simulation of the actuator is made on the quarter section of the actuator by using full 3D finite elements. Vibration characteristics such as fundamental natural frequency, mode shape and output velocity in the frequency range for haptic feeling generation are obtained from the finite element analysis and compared with the experimental results. Experimental results demonstrate that the finite element model is practical and effective enough in predicting the vibration characteristics of the actuator for haptic application. The film actuator shows many promising properties like high transparency, wide range of actuation frequency and high vibration velocity for instance.

scholarly journals Simulation of the dynamic processes of a low-capacity combine harvester movement

2020 ◽  
Vol 164 ◽  
pp. 06009
Author(s):  
Zakhid Godzhaev ◽  
Sergey Senkevich ◽  
Victor Kuzmin ◽  
Ekaterina Ilchenko ◽  
Mikhail Chaplygin ◽  
...  
Keyword(s):  
Software Package ◽  
Vibration Velocity ◽  
Maximum Deviation ◽  
Vibration Displacement ◽  
Small Areas ◽  
Directional Stability ◽  
Different Types ◽  
Direction Of Movement ◽  
Combine Harvester ◽  
Vertical Vibrations

To automate the process of harvesting crops, different types of harvesting machines are required. The most common type of machines used to automate ingathering are harvesters. The use of harvesters for collecting grain crops is rational in fields from 2 hectares. On smaller areas it is not profitable and difficult to apply. For applications in small areas, low-capacity harvesters with a throughput of the thresher up to 1 kg/s (small-sized) may be suitable. The purpose of this study is to analyze the cushioning mass control system of a low-capacity unmanned combine harvester using computer simulation, as well as the simulation of directional stability and turning. To calculate vertical vibrations in the Matlab/Simulink software package, a model of a cushioning system for a wheeled agricultural combine was prepared. In the same software package, simulation of directional stability and turning implementation was carried out. The parameters of vibration displacement, vibration velocity and acceleration, as well as the vibration frequency indicators on the operator's seat are determined. Comparison of the simulation results of the initial and corrected direction of movement of the harvester showed that for this model the maximum deviation from the planned path is a maximum of 10%, which is within acceptable limits. The maximum deviation of the harvester from the course does not exceed the permissible values, which is acceptable accuracy to ensure directional stability.

Comparison of Piezoelectric Structural Damping Based on Velocity Controlled Switching and Pulse Width Modulation Switching Circuits

2012 ◽  
Author(s):  
Dejan Vasic ◽  
Yuan-Ping Liu ◽  
François Costa
Keyword(s):  
Pulse Width Modulation ◽  
Stable State ◽  
Piezoelectric Element ◽  
Voltage Source ◽  
Vibration Velocity ◽  
Constant Voltage ◽  
Vibration Displacement ◽  
Controlled Switching ◽  
The Stability ◽  
Piezoelectric Voltage

Two novel piezoelectric damping techniques (VSD and PWMD) are compared in this paper to the traditional resonant shunt damping technique and SSDV technique. In VSD, the switching shunt circuit turns ON or OFF according to the polarity of the vibration velocity of the host structure to shift the piezoelectric voltage phase. An external voltage source is connected to enlarge the voltage amplitude across the piezoelectric element and to optimize the dissipated power. The PWM shunt technique not only can decrease the audible noises more efficiently but also ensure the stability of the control system with a constant voltage source. The theoretical and the experimental results show that the piezoelectric voltage can be adaptive to the vibration displacement by the pulse widths variation, so the PWMD can stay in stable state with a constant voltage source and can still provide a very good performance.

Dynamic Model of Gears with Trapped Oil and Coupled Analysis in External Spur-Gear Pump

2011 ◽  
Vol 130-134 ◽  
pp. 610-615 ◽  
Author(s):  
Yu Long Li ◽  
Kun Liu ◽  
Fu Chun Sun
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Contact Stiffness ◽  
Spur Gear ◽  
Vibration Characteristics ◽  
Coupled Analysis ◽  
Vibration Velocity ◽  
Gear Pump ◽  
Vibration Displacement ◽  
The Impact

In order to understand the vibration characteristics of gears based on trapped-oil in external spur-gear pump, from the calculations of trapped-oil pressure and hydraulic load and contact stiffness and trapped-oil stiffness, etc., a dynamic model coupled with trapped-oil pressure was derived for the gears, then an iterative operation based on Runge-Kutta method was used for analyzing the model, therefore the data related to trapped-oil pressure and the vibration displacement and the vibration velocity were obtained in a periodic of trapped oil, and the impact of different backlash value and different distance between two unloading grooves on trapped oil pressure and dynamic characteristics of gears was briefly analyzed. All results of simulation showed that trapped-oil pressure and trapped-oil stiffness had greater impact on vibration characteristics of gears in external spur-gear pump, trapped-oil stiffness could reduce the vibration of the gears; in simulation of trapped-oil pressure, dynamic trapped-oil model related to dynamic characteristics of gears more accurate than the static trapped-oil model irrelated to dynamic characteristics of gears; the trapped-oil pressures in two trapped-oil cavity were different, the vibration characteristics of gears was better that in larger backlash value, etc.. Finally, by the trapped-oil stiffness of the external gear pump is unique, the important conclusions are educed that the vibration of gears in external spur-gear pump is indeed different from conventional gears and so on.

Analysis and Application of the Impact Absorption Behavior of the Composite Tube

2013 ◽  
Vol 470 ◽  
pp. 510-515
Author(s):  
Zi Peng Zhang ◽  
Gui Fan Zhao ◽  
Tso Liang Teng ◽  
Yang Wang
Keyword(s):  
Energy Absorption ◽  
Absorption Characteristic ◽  
Beam Model ◽  
Velocity Signal ◽  
Composite Tube ◽  
Acceleration Signal ◽  
Displacement Signal ◽  
Drop Weight Tear Test ◽  
Composite Energy ◽  
The Impact

Composite tube is one new kind of multi-material shell structures. It has both of metal and composite energy absorption advantage. In order to find the energy absorption characteristic of composite tube and put it into use, the Drop-Weight Tear Test (DWTT) was carried out. The LD2Y aluminum was chosen as the inner metal material which was wrapped fiberglass epoxy composite outside. During the test, the displacement signal and velocity signal, acceleration signal were got by piezoelectric acceleration transducer. Furthermore, the DWTT test of the composite tube was simulated in LS-DYNA, and proved the validity of the model by comparing the simulation results with the experiment results. We established the vehicle front longitudinal beam model with the material type of the composite tube, and carried out the simulations of whole car collisions in LS-DYNA according to FMVSS 208. Through the analysis of occupant head injury got from the simulations, we got the result that using the composite tube material could not only elevate the cars safety but also reduce front longitudinal beam weight effectively.

Experimental Evaluation of Vibration Effects Induced by Planed Railway Line on Surrounding Historic Tower

2014 ◽  
Vol 501-504 ◽  
pp. 861-866
Author(s):  
Yuan Tian ◽  
Nan Zhang ◽  
Wei Guo Yang ◽  
Jia Ming Niu
Keyword(s):  
Field Experiments ◽  
Dominant Frequency ◽  
Vibration Velocity ◽  
Vibration Source ◽  
Vibration Level ◽  
Frequency Range ◽  
Structural Vibrations ◽  
Upward Trend ◽  
Railway Line ◽  
Different Types

Using field experiments, the vibration effects of historic tower induced by planed railway line are estimated. The vibrations include the construction vibration and the traffic-induced vibration. The results show that the blasting construction leads to the significant increase in vertical velocity and acceleration. There is no difference between the background vibration of field and foundation of tower. Different types of the sites soil around the tower cause little change. Each measurement time showed an upward trend of vibration level with the increase of frequency. The closer the tower is to the vibration source, the larger the structural vibrations would be. The dominant frequency range for highway-induced vibration is 10-20Hz. For train-induced vibration, the dominant frequency range is more than 40Hz. Surface waves will result in amplification phenomenon of vibration velocity of ancient structures within a certain range.

scholarly journals SIGNAL PHASE SHIFTS DURING THE MEASUREMENT OF VIBRATION PARAMETERS

2020 ◽  
pp. 100-104
Author(s):  
Передерко А.Л., к.т.н.
Keyword(s):  
Vibration Signal ◽  
Wide Band ◽  
Phase Shifts ◽  
Vibration Velocity ◽  
Measured Signal ◽  
Mechanical Shock ◽  
Vibration Displacement ◽  
Active Vibration ◽  
Vibration Parameters ◽  
And Control

In systems of vibration control, monitoring, diagnostics, active vibration protection, measurements and control of vibration parameters are necessary. For this, piezoelectric sensors are widely used in them as primary transducers. These sensors, due to their high metrological characteristics, such as accuracy, speed, a wide band of operating frequencies and temperatures, are traditionally used to measure vibration displacement, vibration velocity and vibration acceleration. The use of these types of sensors is necessary due to the need to measure and control vibration at objects with different frequency characteristics. The article considers possible distortions of the measured signal at the output of the sensors due to phase shifts. These phase shifts must be taken into account when developing and constructing measurement and processing schemes of the vibration signal. This is especially true when measuring and recording a rapid vibration processes, such as mechanical shock.

scholarly journals The processing results of the vibration records from the dams and coastal slopes of the Charvak and Andijan water reservoirs of Uzbekistan during the weak earthquakes

2020 ◽  
Vol 2 (4) ◽  
pp. 28-42
Author(s):  
Lutfulla Khamidov ◽  
Alisher Ibragimov ◽  
Ilkhom Alimukhamedov ◽  
Khairulla Khamidov
Keyword(s):  
Seismic Data ◽  
Reference Station ◽  
Vibration Velocity ◽  
Monitoring Systems ◽  
Vibration Frequencies ◽  
Frequency Range ◽  
Water Reservoirs ◽  
Seismic Monitoring Systems ◽  
Linear Behavior ◽  
Weak Earthquakes

The article discusses the processing results of the vibration records from the dams and coastal slopes of the Charvak and Andijan water reservoirs of Uzbekistan during the weak earthquakes. It is shown, that the seismic monitoring systems were upgraded at the investigated objects. Analyzing seismic estimates, revealed, that the construction of the Charvak reservoir dam has a non-linear behavior, and it is manifested in the differences of the frequency range and transmission coefficient of the dam elements. According to the analysis of seismic data, obtained during the registration of weak earthquakes at the several measuring points of dams and coastal slopes of the Charvak and Andijan reservoirs, the vibration frequencies and the ratio of the vibration velocity amplitudes to the vibration velocity amplitudes of the reference station are varies greatly depending on the azimuth to the epicenter

scholarly journals Capacitive Sensor Accuracy Optimisation by the Frequency Range Appropriate Choice

2021 ◽  
Author(s):  
Zine Ghemari ◽  
Salah Belkhiri
Keyword(s):  
Measurement Error ◽  
Natural Frequency ◽  
Relative Frequency ◽  
Model Simulation ◽  
Capacitive Sensor ◽  
Vibration Sensor ◽  
Electronic Instrument ◽  
Frequency Range ◽  
Rotating Machine ◽  
Sensor Accuracy

Abstract Measuring rotating machine vibrations requires an electronic instrument called a vibration sensor. In this work, the vibration sensor with capacitive detection is chosen to measure the vibrations movement. In order to fulfill the objectives of reducing the measurement error and achieving high sensor accuracy, this sensor is modeled by the application of motion law. The results obtained by the developed model simulation showed that it was possible to extract a formula linked to relative frequency of the vibrating structure and to the capacitive sensor natural frequency, this makes it possible to reduce the measurement error and improve the capacitive sensor accuracy

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