scholarly journals ANALYSIS OF MECHANICAL VIBRATION OF A SERVOMOTOR USING VIBROMETRY

2021 ◽  
Vol 24 (2) ◽  
pp. 13-19
Author(s):  
Štefánia Olejárová ◽  
Keyword(s):  
Service Life ◽  
Frequency Spectrum ◽  
Mechanical Vibration ◽  
Vibration Acceleration ◽  
Initial Information ◽  
Experimental Part ◽  
Objective State

The servomotor must ensure resistance to the environment (mechanical vibration, humidity, temperature) in which it will be operated. It is the vibration that is one of the important monitored parameters that allow obtaining initial information about the operational status of the equipment. Exceeding the preset limits adversely affects the service life and reliability of the components. The experimental part is focused on recording and analyzing the magnitude of vibration acceleration, through frequency spectrum and its comparison with the envelopes of frequency spectrums. The obtained graphical dependencies from the experiments are a suitable basis for the assessment of the objective state.

scholarly journals The Relationship between Vibratory Sensation and Body Surface Vibration Induced by Low-Frequency Noise

2002 ◽  
Vol 21 (2) ◽  
pp. 87-100 ◽  
Author(s):  
Yukio Takahashi ◽  
Kazuo Kanada ◽  
Yoshiharu Yonekawa
Keyword(s):  
Body Surface ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
The Body ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Vibration Acceleration ◽  
Surface Vibration ◽  
Human Body Surface ◽  
The Relationship

Human body surface vibration induced by low-frequency noise was measured at the forehead, the chest and the abdomen. At the same time, subjects rated their vibratory sensation at each of these locations. The relationship between the measured vibration on the body surface and the rated vibratory sensation was examined, revealing that the vibratory sensations perceived in the chest and abdomen correlated closely with the vibration acceleration levels of the body surface vibration. This suggested that a person exposed to low-frequency noise perceives vibration at the chest or abdomen by sensing the mechanical vibration that the noise induces in the body. At the head, on the other hand, it was found that the vibratory sensation correlated comparably with the vibration acceleration level of the body surface vibration and the sound pressure level of the noise stimulus. This finding suggested that the mechanism of perception of vibration in the head is different from that of the perception of vibratory sensation in the chest and the abdomen.

scholarly journals Frequency spectrum of the human head–neck to mechanical vibrations

2017 ◽  
Vol 37 (3) ◽  
pp. 611-618 ◽  
Author(s):  
Bin Yang ◽  
Zheng Shi ◽  
Qun Wang ◽  
Feng Xiao ◽  
Tong-Tong Gu ◽  
...  
Keyword(s):  
Finite Element ◽  
Frequency Spectrum ◽  
Mechanical Vibration ◽  
Three Dimensional ◽  
Human Head ◽  
Element Model ◽  
Mode Shapes ◽  
Joint Disorder ◽  
Biomechanical Responses ◽  
Head Neck

This study is based on a real finite element human head–neck model and concentrates on its numerical vibration characteristic. Frequency spectrum and mode shapes of the finite element model of human head–neck under mechanical vibration have been calculated. These vibration characteristics are in good agreement with the previous studies. The simulated fundamental frequency of 35.25 Hz is fairly similar to the published documents, and rarely reported modal responses such as “mastication” and flipping of nasal lateral cartilages modes, however, are introduced by our three-dimensional modal analysis. These additional modes may be of interest to surgeons or clinicians who are specialized in temporomandibular or rhinoplasty joint disorder. Modal validation in terms of modal shapes proposes a necessity for elaborate modeling to identify each individual part’s extra frequencies. Furthermore, it also studies the influence of damping on resonant frequencies and biomechanical responses. It is discovered that damping has an inverse proportionality between damping effect on natural frequency and that on biomechanical responses.

scholarly journals APPLICATION OF WC GRAINS BY DEPOSITION BRAZING

2021 ◽  
Vol 2021 (4) ◽  
pp. 4857-4862
Author(s):  
MARIAN SIGMUND ◽  
◽  
JOSEF IZAK ◽  
Keyword(s):  
Service Life ◽  
Cutting Tools ◽  
Base Material ◽  
Filler Material ◽  
Weld Deposit ◽  
Experimental Part ◽  
Base Matrix ◽  
Nickel Base ◽  
Flame Method ◽  
Specific Part

The article describes problems of hard depositional brazing of wolfram-carbide grains in various matrixes. Especially iron and nickel base matrix on base material from constructional carbon steel. The experimental part was brazed by oxyacetylene flame (method 912 according to EN ISO 4063). The major goals of the experiment were to describe the technological procedure of hard depositional brazing of this specific part. Consequently, were proved wolfram-carbide deposit on two test coupons. These test coupons were metallographically and qualitatively evaluated. The advantage of wolfram-carbide depositional brazing is a service life of deposit, that could be multiple higher, than standard weld deposit with carbon, chromium and vanadium filler material. The advantage is also costly because this kind of braze is cheaper than hard surfacing filler material. This specific application of the wolfram-carbide layer is one of the hardest coatings that could be by flame brazing technology performed. Usage of this application is for example in the mining, woodcutting industry, where it is necessary to improve abrasion and resistance, service life, and guaranteed durability or hardness for cutting tools.

scholarly journals Self-Powered Acceleration Sensor Based on Multilayer Suspension Structure and TPU-RTV Film for Vibration Monitoring

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2763
Author(s):  
Xiaotao Han ◽  
Qiyuan Zhang ◽  
Junbin Yu ◽  
Jinsha Song ◽  
Zhengyang Li ◽  
...  
Keyword(s):  
Short Circuit ◽  
Mechanical Vibration ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Vibration Monitoring ◽  
Triboelectric Nanogenerator ◽  
Acceleration Sensor ◽  
Vibration Acceleration ◽  
Self Powered ◽  
Suspension Structure

In this paper, we designed a triboelectric acceleration sensor with excellent multiple parameters. To more easily detect weak vibrations, the sensor was founded on a multilayer suspension structure. To effectively improve the electrical properties of the sensor, a surface roughening and internal doping friction film, which was refined with a room temperature vulcanized silicone rubber (RTV) and some thermoplastic polyurethanes (TPU) powder in a certain proportion, was integrated into the structure. It was found that the optimization of the RTV film increases the open circuit voltage and short circuit current of the triboelectric nanogenerator (TENG) by 223% and 227%, respectively. When the external vibration acceleration is less than 4 m/s2, the sensitivity and linearity are 1.996 V/(m/s2) and 0.999, respectively. Additionally, when it is in the range between 4 m/s2 and 15 m/s2, those are 23.082 V/(m/s2) and 0.975, respectively. Furthermore, the sensor was placed in a simulated truck vibration environment, and its self-powered monitoring ability validated by experiments in real time. The results show that the designed sensor has strong practical value in the field of monitoring mechanical vibration acceleration.

scholarly journals Investigation of Distribution Transformers Vibrations in Terms of Core and Winding Condition Assessment

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 13
Author(s):  
Jaroslaw Gielniak ◽  
Magdalena Czerniak
Keyword(s):  
Trend Analysis ◽  
Frequency Spectrum ◽  
Condition Assessment ◽  
The State ◽  
Active Part ◽  
Power Transformers ◽  
Vibration Acceleration ◽  
Large Share ◽  
Distribution Transformers ◽  
Different Types

This work refers to the criterion values used to assess the state of the active part of the transformer based on the analysis of the effective value of the total vibration acceleration and the frequency spectrum. It was proved in the work that the criteria values should be differentiated for transformers of different rated power. Transformers with lower rated power are characterized by lower RMS values of vibration acceleration than units with higher rated power, which cannot remain without impact on the criteria values. Trend analysis of the total aRMS values may reveal increasing defects before the currently applicable criteria values are exceeded. In addition, the influence of the position of the sensor on the frequency spectrum of the obtained signals was analyzed. It was proved that the sensors should be mounted in the middle of the transformer tank, between its lower part and the cover. The dependence of RMS value of vibration acceleration on no-load losses was also determined for transformers of different types but the same rated power. This relationship will not have a large share in the total vibrations of the transformer, due to slight changes in the value of aRMS occurring for all analyzed units.

Detection of Rail Fastener Conditions Using Time-Frequency Entropy Based on Orthogonal Empirical Mode Decomposition

2013 ◽  
Vol 333-335 ◽  
pp. 1708-1712 ◽  
Author(s):  
Chong Liu ◽  
Li Hua Zhang ◽  
Tong Qun Ren ◽  
Jun Sheng Liang ◽  
Da Zhi Wang ◽  
...  
Keyword(s):  
Empirical Mode Decomposition ◽  
Frequency Spectrum ◽  
Vibration Signal ◽  
Vertical Vibration ◽  
Intrinsic Mode Functions ◽  
Acceleration Response ◽  
Vibration Acceleration ◽  
Time Frequency ◽  
Mode Decomposition ◽  
Outdoor Experiment

A method based on OEMD (Orthogonal Empirical Mode Decomposition) and the theory of time-frequency entropy was applied to detect different rail fastener conditions. The original vertical vibration acceleration response of rail under different fastening conditions was obtained from outdoor experiment. The OEMD method was used to get orthogonal IMFs (Intrinsic Mode Functions) of the original vibration signal. The Hilbert time-frequency spectrum was then obtained based on the orthogonal IMFs and corresponding entropy was calculated and compared. The results show that the method is available to detect different rail fastener conditions.

scholarly journals Analysis of general and local vibration at the workplace: the operator of a specialist road machine

2019 ◽  
Vol 20 (1-2) ◽  
pp. 281-286
Author(s):  
Paweł Kiełbasa ◽  
Tomasz Dróżdż ◽  
Dominika Wojtas
Keyword(s):  
Mechanical Vibration ◽  
Mean Value ◽  
Steering Wheel ◽  
Vibration Exposure ◽  
Vibration Acceleration ◽  
Local Vibration ◽  
Limit Values ◽  
Working Age ◽  
General Action ◽  
The Mean

The article discusses an attempt to evaluate the ergonomic vibration environment of selected technical sources used in various technological processes. The scope of the tests included measurement of general vibrations in the plane of the seat carrier and local vibrations occurring on the steering wheel of selected technical sources. The tests were carried out in two trucks and in a vibratory road roller. The measurements were carried out in 10 repetitions for each technical measure. On the basis of the obtained measurements, the mean value of vibration acceleration, effective vibration acceleration and peak vibration acceleration as well as the weighted vibration acceleration value were determined. The obtained results were confronted with the applicable standards. It was noted that the daily vibration exposure of general action in the case of road roll works in the horizontal direction was 1,11 m∙s-2 and exceeded the limit values for men and women in the working age. In the case of other vehicles tested, there was no exceedance of the permissible mechanical vibration value in any of the analyzed directions and do not pose a threat to the employee.

Study on Dynamic Characteristics of Parallel Robot with 2-DOF

2013 ◽  
Vol 397-400 ◽  
pp. 1558-1562
Author(s):  
Mei Yu Chen ◽  
Hong Bing Xin ◽  
Quan Lai Li ◽  
Yue Fei Xin ◽  
Deng Qi Cui ◽  
...  
Keyword(s):  
Motion Control ◽  
Frequency Spectrum ◽  
Frequency Analysis ◽  
Dynamic Characteristics ◽  
Experimental System ◽  
Parallel Robot ◽  
Acceleration Response ◽  
Vibration Acceleration ◽  
Set Up

The experimental system of dynamic characteristics is set up to improve the dynamics performance and motion control quality of 2-DOF robot. The vibration acceleration response of the end actuator is measured at different speeds in two directions vertical and parallel to the workbench plane. The frequency spectrum is obtained through frequency analysis to provide a basis to improve the performance of robot.

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