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1
Dapeng, Zhu, Qin Liangkai, and Lin Yundian. "Analytical Study on Dynamic Response of Deep Foundation Pit Support Structure under the Action of Subway Train Vibration Load: A Case Study of Deep Foundation Pit of the New Museum Near Metro Line 2 in Chengdu, China." Shock and Vibration 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/535196.
Повний текст джерелаАнотація:
Presently, foundation pit support structures are generally regarded as the temporary structures and the impact of vibration loads is often overlooked. As opposed to static and seismic loads, the vibration loads of subway trains are a type of cyclic load with a relatively long duration of action and a definite cycle; it is of great importance for the design of foundation pit support structures to correctly evaluate the impact of subway train vibrations on deep foundation pit and support works. In this paper, a dynamic three-dimensional numerical model is built that considers the vibration load of subway trains on the basis of the static numerical model for deep foundation pit support structures and simplified train loads to study the impact of train vibrations on deep foundation pit and permanent support structures. Studies have shown that the dynamic response of surface displacement mainly occurs in the early period of dynamic load, the vibration load of subway trains has little impact on ground subsidence, the support pile structure is in an elastic state during dynamic response under the action of subway train vibrations, and the action of train vibration loads is inimical to the safety of foundation pit support structures and should be closely studied.
2
Niu, Jianye, Jiang Wu, Qiming Liu, Li Chen, and Shijie Guo. "A Dumbbell Shaped Piezoelectric Motor Driven by the First-Order Torsional and the First-Order Flexural Vibrations." Actuators 9, no. 4 (November 30, 2020): 124. http://dx.doi.org/10.3390/act9040124.
Повний текст джерелаАнотація:
A piezoelectric motor driven by the first-order torsional and first-order flexural (T/F) vibrations is designed, fabricated, and tested in this study. The actuating force is generated by the torsional vibration of the dumbbell-shaped vibrator, while the elliptical motion shape is adjusted with the flexural vibration. The rotor, pressed onto the vibrator’s lateral surface, is frictionally driven with the vibrator. Here, the torsional vibration, the shear modes of piezoelectric ceramics, and the driving method may contribute to high torque and high output power. To test the feasibility of our proposal, first, a prototype of the T/F vibrator is built and its vibration properties are explored. As predicted, the torsional and flexural vibrations are excited on the vibrator. Then, the load characteristics of the piezoelectric motor are investigated. The maximal torque, the no-load rotation speed, and maximal output power are 4.3 Nm, 125 r/min, and 16.9 W, respectively. The results imply that using the first-order torsional and the first-order flexural vibrations is a feasible method to achieve high torque and high output power of piezoelectric motors.
3
GODZHAEV, Z. A., V. V. SHEKHOVTSOV, M. V. LIASHENKO, A. I. ISKALIEV, and P. V. POTAPOV. "TEST STAND FOR VIBRATION ISOLATORS OF VEHICLE CABIN SUSPENSION." Fundamental and Applied Problems of Engineering and Technology, no. 5 (2021): 165–73. http://dx.doi.org/10.33979/2073-7408-2021-349-5-165-173.
Повний текст джерелаАнотація:
Modern vehicles includes a cabin suspension that provides reducing of amplitudes of vibration impacts on the cabin and if possible absorption of vibration energy portion. The cabin suspension includes vibration isolators which have various constructions and operation principles: mechanical, hydraulic, pneumatic and combined mechanisms. Stand tests provides evaluation of vibration isolators ability to reduce amplitudes of impacts on the cabin from the vehicle frame down to a necessary level during normative lifetime. This paper presents the description of the tests stand for life tests of a vehicle cabin suspension created in VSTU. Vibration isolators of a vehicles cabin suspension are impacted by loads from vertical, longitudinal– and lateral–angular cabin vibrations during exploitation. At this all load impacts have various amplitudes and time profiles. Proposed test stand provides reproduction of operational load regimes for vibration isolators testing by scheme of the loading device. This device consists of three controlled electric motors which are oriented in vertical, longitudinal and lateral axial directions and cam eccentrics mounted on motors shafts. These eccentrics may have different or similar profiles and provides impact on the loading platform. So it is possible to reproduce operational loads from vertical, longitudinal– and lateral–angular cabin vibrations on tested vibration isolators at that vibrations may have various amplitudes, frequencies and time profiles for every load impact to increase reliability of the test results.
4
Farrokhi Zanganeh, Niusha, Gholamhossein Shahgholi, and Soleiman Agh. "Studying the Effect of Balancer on Engine Vibration of Massey Ferguson 285 Tractor." Acta Technologica Agriculturae 24, no. 1 (January 29, 2021): 14–19. http://dx.doi.org/10.2478/ata-2021-0003.
Повний текст джерелаАнотація:
Abstract The mechanical vibration causes health issues to drivers, such as backache, spinal cord injury, etc. In this regard, a tractor engine plays important role. Tractors without chassis are equipped with a balancer unit reducing the secondary engine vibrating force and decreasing the engine and tractor vibration. The paper presented investigates the effects of balancer on secondary vibration. In this research, the root mean square (RMS) of vibration was computed for specific periods of engine work. Effects of rotational speed and engine load on engine vibration in two modes with and without balancer were investigated. The results showed that, at full engine load, increasing the engine speed resulted in increasing the vibration in both observed modes. Balancer utilization reduced the vibration by 22.3% on average. At fixed rotational speed, increasing load caused an increase in vibration in both observed modes. At 1400 rpm rotational speed and 125 Nm torque, balancer utilization managed to reduce the RMS of secondary vibration by 38.9%. Furthermore, at 250 Nm, RMS vibrations were reduced by 21.3% in comparison to no balancer mode. At full load, variable rotational speed, the balancer significantly reduced vibration by 29% on average. The balancer proved to be more efficient at lower torques.
5
Kaminsky, R. V., I. V. Kovaltsov, E. A. Kostyukov, S. V. Sibiryakov, and A. S. Filippov. "Vibration analysis of diesel turbocharger for agricultural use." Traktory i sel hozmashiny 85, no. 5 (October 15, 2018): 47–55. http://dx.doi.org/10.17816/0321-4443-66414.
Повний текст джерелаАнотація:
Environmental, efficiency and economic requirements for diesel engines are being constantly toughened, thus requiring engine modernization. Increasing the degree of diesel boosting is one of the ways to meet these requirements. However, this leads to an increase of the load on various parts and components of the diesel engine. The turbocharger, as one of the most important engine units, undergoes a high vibration load due to the high rotor speed. As it is known from the practice of the manufacturer, this is one of the most common causes of failure of turbochargers. So the evaluation of the vibration load of the plain bearings in modern turbo-charging units requires careful research, which is the purpose of this work. To measure vibrations in the turbocharger, there was used a three-axis vibration transducer AR81, which was mounted on the turbocharger in such a way that the sensor axes coincided with the axes of the turbocharger. This is necessary to determine both the magnitude of the vibrations, and their direction. According to the measured values of vibration acceleration, it can be concluded that the turbocharger is technically in order, predicted a possible failure and, consequently, taken a decision on the required set of measures or make changes to the design documentation in the case of significant deviations. The study was undertaken in two stages: on a specialized balancing machine and on a gas-dynamic non-motorized bench. During the tests there were detected harmonic and non-harmonic components, resonances associated with an increase in the rotor speed. The values of vibration acceleration along the rotor axis of the turbocharger have been measured, perpendicular to the rotor axis in the horizontal plane, perpendicular to the rotor axis in the vertical plane. According to the results of the experimental data, there have been drawn the conclusions that allow to note the following: to reduce the vibrational loads on the running part of the turbocharger, it is necessary to design the compressor stage in such a way that in all modes of engine operation there would be a substantial margin up to the surging limit; the radial load is significantly higher than the axial load, so the radial bearing must have a significant margin of safety to increase the reliability of the turbocharger.
6
Shuai, Chang-geng, Bu-yun Li, Jian-guo Ma, and Zhao-hao Yang. "A Novel Low Stiffness Air Spring Vibration-Isolation Mounting System." Shock and Vibration 2022 (February 21, 2022): 1–11. http://dx.doi.org/10.1155/2022/5598689.
Повний текст джерелаАнотація:
Quasi-zero-stiffness (QZS) structures offer substantial practical benefits for facilitating the essential support and isolation of vibrational source loads aboard modern marine vessels. In order to design a compact QZS system of high bearing capacity, the article proposes a low stiffness air spring (LSAS) vibration-isolation mounting system composed of both vertical and lateral air springs. The vertical air springs support the load and isolate vibrations in the vertical direction, while the lateral air springs support the load and isolate transversal vibrations. Theoretical analyses based on a simple two-dimensional, single degree of freedom model demonstrate that the proposed novel LSAS design decreases the degree of stiffness in the support structure that would otherwise be induced by introducing lateral air springs and accordingly increases the vibration isolation effect. Moreover, optimization of the air spring parameters enables the lateral air springs to provide negative stiffness and thereby realize QZS characteristics. Experimental testing based on prototypes of a standard air spring mounting system and the proposed LSAS mounting system demonstrates that the stiffness of the proposed system is about 1/5 that of the standard system. Accordingly, the proposed structure design successfully alleviates the undesirable influence of lateral air springs on the stiffness of the mounting system.
7
Huang, Yu Yang, Laszlo Horvath, and Péter Böröcz. "Measurement and Analysis of Industrial Forklifts Vibration Levels for Unit Load Testing Purposes." Applied Sciences 11, no. 7 (March 24, 2021): 2901. http://dx.doi.org/10.3390/app11072901.
Повний текст джерелаАнотація:
Forklifts are one of the most common types of material handling equipment used in warehouses and distribution centers. Vibration generated by forklifts may have an effect on the performance of unit loads and product damage rates. Historical research projects have focused predominantly on the measurement of vibration for over-the-road transportation. Thus, there is still a lack of understanding of the level of vibration caused by forklifts. The goal of this study was to understand how the vibration that is experienced by unit loads while being transported by forklifts is affected by factors such as speed, road condition, unit load weight, type of forklift, and sensor location. For this study, power spectral density (PSD) measurements were collected using a Lansmont Saver 9X30 data logger. Vibration levels were measured for three different industrial forklifts on two different surface types. The forklifts were driven at two different speeds while carrying two different unit load weights. For all of these conditions, the vibration levels were measured at the forklift carriage, at the back of the fork tine heel, and at the fork tine tips. The results obtained show that the highest vibrational intensity occurred at 3–4 Hz, while the highest overall Grms value observed was 0.145 G2/Hz (between 1–200 Hz). An increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the unit load weight carried by the forklift caused a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift had the highest vibration intensity, and all forklifts, when driven on asphalt, experienced more vibration.
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Nasirshoaibi, Mehrdad, Nader Mohammadi, and Masih Nasirshoaibi. "Forced Transverse Vibration of a Closed Double Single-Walled Carbon Nanotube System Containing a Fluid with Effect of Compressive Axial Load." Shock and Vibration 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/435284.
Повний текст джерелаАнотація:
Based on the Rayleigh beam theory, the forced transverse vibrations of a closed double single-walled carbon nanotube (SWCNT) system containing a fluid with a Pasternak layer in-between are investigated. It is assumed that the two single-walled carbon nanotubes of the system are continuously joined by a Pasternak layer and both sides of SWCNTs containing a fluid are closed. The dynamic responses of the system caused by arbitrarily distributed continuous loads are obtained. The effect of compressive axial load on the forced vibrations of the double single-walled carbon nanotube system is discussed for one case of particular excitation loading. The properties of the forced transverse vibrations of the system are found to be significantly dependent on the compressive axial load. The steady-state vibration amplitudes of the SWCNT decrease with increasing of length of SWCNT. Vibrations caused by the harmonic exciting forces are discussed, and conditions of resonance and dynamic vibration absorption are formulated. The SWCNT-type dynamic absorber is a new concept of a dynamic vibration absorber (DVA), which can be applied to suppress excessive vibrations of corresponding SWCNT systems.
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Li, Guang Hui, Zhen Yu Wang, Guo Peng Liao, and Guang Yu Tan. "Experimental Study on Critical Vibration for the Load of Motion Platform of Linear Servo Motor." Key Engineering Materials 522 (August 2012): 613–17. http://dx.doi.org/10.4028/www.scientific.net/kem.522.613.
Повний текст джерелаАнотація:
Motorized spindle is an execution unit of machine tool. The rotation of a motorized spindle and the cutting of a machine tool are two vibration sources which will impact the feed system. These vibrations will affect processing quality, cause tools failure and destroy machine stability. The signal analysis in time-domain and frequency-domain for two types of vibrations of execution unit load of linear servo motor were conducted respectively in this work, by employing the BZ7201-USB multifunctional data acquisition instrument. From the analysis, the impact of vibration load to the motion precision of execution unit was obtained. As the load vibration will cause overshoot problem as well, the critical vibration range of motion platform was obtained from a research on system PID parameter adjustment for overshoot problem. The results provide experimental data for further research on servo feed system control.
10
Gunasekaran, Vijay, Jeyaraj Pitchaimani, and Lenin Babu Mailan Chinnapandi. "Free vibration and inherent material damping characteristics of boron-FRP plate: influence of non-uniform uniaxial edge loads." International Journal for Simulation and Multidisciplinary Design Optimization 12 (2021): 18. http://dx.doi.org/10.1051/smdo/2021017.
Повний текст джерелаАнотація:
The current investigation presents the analytical investigation on free vibration and inherent material damping of boron-FRP plate, subjected to non-uniform uniaxial edge loads. Initially critical buckling load (Pcr) is obtained, then followed by free vibration response and inherent material damping values for corresponding modal indices of the FRP plate is calculated for different load fraction of non-uniform uniaxial edge loads. The buckling load and free vibration response are obtained by using strain energy method and Reddy's TSDT respectively. It is observed that the nature of load and aspect ratio influence the bucking, free vibration and inherent material damping behaviour of the fibre reinforced polymer plate significantly.
11
Yeh, Wei Ching, Tsuh Siao Chu, Shiuan Sheng Wang, Kuang Hua Fuh, and Kuan Hun Chen. "Finite Element Analysis of Blanking Process by Superimposing Ultrasonic Vibrations." Advanced Materials Research 201-203 (February 2011): 126–32. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.126.
Повний текст джерелаАнотація:
The application of ultrasonic vibrations superimposed on wire drawing, deep drawing, upsetting and rolling has been developed in the literature. No attempts have ever been made to develop the application of the ultrasonic vibration to blanking process. This paper reports an investigation into the effects of the superimposed ultrasonic vibrations of the die during the blanking process by finite element software DEFORM-2D. The results are compared with the conventional blanking experiment by Hatanaka and Yamaguchi [7] and the simulations are analyzed with various vibration directions, amplitudes and frequencies. The effects of the ultrasonic vibration on the punch load, flow stress and edge profile are systematically studied. The results show ultrasonic vibration can decrease the punch load and improve the quality of edge profile by increasing the vibration amplitudes and frequencies.
12
Pelchen, Christoph, and Jo¨rg Wauer. "Small Vibrations of Rotating Ring Segments and Full Rings Under External or Internal Pressure." Journal of Applied Mechanics 59, no. 4 (December 1, 1992): 1038–40. http://dx.doi.org/10.1115/1.2894023.
Повний текст джерелаАнотація:
The combined effect of a radial pressure load and a centrifugal field on the vibrations of an inextensible, circular, slender ring structure is treated. First, the stationary pre-buckling state of the segment or the full ring is specified. Then small oscillations about this configuration are investigated. The variations of vibration frequencies with the pressure load and the speed rate are examined and possible buckling loads are determined.
13
Bouaziz, Hamza, Nicolas Peyret, Mohamed Slim Abbes, Gael Chevallier, and Mohamed Haddar. "Vibration Reduction of an Assembly by Control of the Tightening Load." International Journal of Applied Mechanics 08, no. 06 (September 2016): 1650081. http://dx.doi.org/10.1142/s1758825116500812.
Повний текст джерелаАнотація:
Due to their lightness, the aerospace structures are vulnerable to vibrations. Their amplitudes need to be mitigated through damping devices. The aim of this paper is to control the tightening force of a bolted joint in order to improve the vibration reduction. The work focuses on a single vibration mode modeled by two degrees of freedom coupled with a Jenkins’ cell. Then two control strategies are proposed in order to reduce the harmonically forced vibrations and transient vibrations. The first control law uses a constant optimum clamping for each excitation level. The second law consists in a sinusoidal variation of the clamping force adapted to each level and frequency of excitation. Finally, in the third section, the control law is modified in order to reduce transient vibrations. For each control law, the performances of the model are discussed according to the aimed application.
14
Ren, W. J., L. Wang, Q. H. Mao, S. B. Jiang, and S. Huang. "Coupling Properties of Chain Drive System under Various and Eccentric Loads." International Journal of Simulation Modelling 19, no. 4 (December 5, 2020): 643–54. http://dx.doi.org/10.2507/ijsimm19-4-535.
Повний текст джерелаАнотація:
The chain drive system is a core subsystem of heavy scraper conveyors. During operation, violent oscillations of fluctuating loads on the chain and uneven loads at the two chain sides are observed, thus intensifying chain wear and even causing chain breakage. The dynamic properties of a chain drive system under various load and eccentric load were discussed thoroughly by combining dynamic and discrete element coupling analyses to improve the reliability of the scraper conveyor. Based on the discrete element method and multibody dynamic theory, a coupling analysis model of a scraper conveyor was constructed, and a simulation analysis on coal conveying process under various load and eccentric load was carried out. Simulation results demonstrate that the transverse vibration of the chain is positively related to coal conveying quantity, whereas longitudinal vibration is negatively correlated to coal conveying quantity. The transverse vibration rate under full loads is 513.62 % higher than that under idle condition, while the longitudinal vibration rate is 53.44 % lower. The effects of coals on transverse vibration and longitudinal vibration of a chain ring are opposite.
15
Kastawan, I. Made Wiwit. "Effect of load current harmonics on vibration of three-phase generator." MATEC Web of Conferences 197 (2018): 11023. http://dx.doi.org/10.1051/matecconf/201819711023.
Повний текст джерелаАнотація:
Almost all today electrical loads are considered non-linear such as switch mode power supply (SMPS) for powering computer and mobile phone or variable speed drive (VSD) for driving home and industrial electric motors. These loads generate ac non-sinusoidal current containing a lot of harmonics as indicated by its high total harmonics distortion (THD) figure. Current harmonics bring negative effects into all electrical power system components, including three-phase generator. This paper provides analysis of load current harmonics effects on vibration of three-phase generator. Three different laboratory experiments have been conducted i.e. three-phase linear resistive loading, non-linear loading with a three-phase ac/dc converter and non-linear loading with three single-phase capacitor filtered ac/dc converters. Results show that the higher load current harmonics content the higher is vibration of the three-phase generator. Non-linear loading with a three-phase ac/dc converter that generate about 24.7% THD gives an increase of 4.3% and 5.5% in average of vertical and horizontal vibrations of the three-phase generator respectively. Further, non-linear loading with three single-phase capacitor filtered ac/dc converters that generate THD as high as 74.9% gives significant increase of 28.1% and 23.6% in average of vertical and horizontal vibrations respectively.
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Nuraliyev, Almukhan, and Mukhtorkhon Ibadullayev. "Research and development of resonant electromagnetic vibration screen for intensive vibration technologies." E3S Web of Conferences 216 (2020): 01114. http://dx.doi.org/10.1051/e3sconf/202021601114.
Повний текст джерелаАнотація:
In the article the development and use of controlled electromagnetic vibration drives used in the field of intensive vibration technologies are considered. Method is proposed for adjustment of amplitude and frequency of vibration of working element of vibrating screen, which improves efficiency of cutting, its dynamic and energy indices. By solving the differential equations of the system, its main characteristics, which can be used in the calculation and design of electromagnets, are determined. For experimental research, a vibrator was developed with a drive from a two-stroke electromagnetic exciter. Based on the results of the studies, it was established that the adjustment of the near-resonance mode when the load changes can always be provided by changing the frequency of the thyristor converter voltage pulses. Optimal combinations of amplitudes and oscillation frequencies of the developed vibration sieve are determined.
17
Bucchi, F., and P. Forte. "Simulation of the Vibratory Behavior of Slender Shafts Subject to Transverse Loads Moving in the Axial Direction." Shock and Vibration 2020 (January 3, 2020): 1–10. http://dx.doi.org/10.1155/2020/2905341.
Повний текст джерелаАнотація:
In various machines of the manufacturing industry, and in particular in paper converting machinery, there are shafts operating under conditions similar to that of a slender beam subjected to a transverse load moving in the axial direction. This condition can lead to vibrations and consequent deterioration of the machine performance and of the product quality. The problem has been theoretically studied in the literature since the 1990s. While shaft mass and stiffness are universally considered among the most influential parameters on its vibratory behavior, less obvious and not investigated in the literature is the influence of the spatial interval between two successive loads, an aspect that should be considered in the shaft design phase. In fact, if that is less than the length of the shaft, i.e., if there is more than one transverse load on the shaft at a given time, the vibration level may decrease with respect to the single-load configuration. This work describes the development of a mathematical model of a slender shaft hinged at its ends, representing the rotor of a paper roll perforating unit, with the SW Mathematica. The effect of a load moving axially at a given speed followed by similar loads after given spatial intervals was simulated investigating the influence of speed and load interval on shaft vibrations and resonance. The results showed how reducing the load interval can lead to a reduction of the shaft vibration which is a useful indication on possible design corrective actions.
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Malliotakis, Georgios, Panagiotis Alevras, and Charalampos Baniotopoulos. "Recent Advances in Vibration Control Methods for Wind Turbine Towers." Energies 14, no. 22 (November 11, 2021): 7536. http://dx.doi.org/10.3390/en14227536.
Повний текст джерелаАнотація:
Wind power is a substantial resource to assist global efforts on the decarbonization of energy. The drive to increase capacity has led to ever-increasing blade tip heights and lightweight, slender towers. These structures are subject to a variety of environmental loads that give rise to vibrations with potentially catastrophic consequences, making the mitigation of the tower’s structural vibrations an important factor for low maintenance requirements and reduced damage risk. Recent advances in the most important vibration control methods for wind turbine towers are presented in this paper, exploring the impact of the installation environment harshness on the performance of state-of-the-art devices. An overview of the typical structural characteristics of a modern wind turbine tower is followed by a discussion of typical damages and their link to known collapse cases. Furthermore, the vibration properties of towers in harsh multi-hazard environments are presented and the typical design options are discussed. A comprehensive review of the most promising passive, active, and semi-active vibration control methods is conducted, focusing on recent advances around novel concepts and analyses of their performance under multiple environmental loads, including wind, waves, currents, and seismic excitations. The review highlights the benefits of installing structural systems in reducing the vibrational load of towers and therefore increasing their structural reliability and resilience to extreme events. It is also found that the stochastic nature of the typical tower loads remains a key issue for the design and the performance of the state-of-the-art vibration control methods.
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Barati, Mohammad Reza, and Hossein Shahverdi. "Forced vibration of porous functionally graded nanoplates under uniform dynamic load using general nonlocal stress–strain gradient theory." Journal of Vibration and Control 24, no. 20 (September 29, 2017): 4700–4715. http://dx.doi.org/10.1177/1077546317733832.
Повний текст джерелаАнотація:
Forced vibration analysis of porous functionally graded nanoplates under uniform dynamic loads is performed based on generalized nonlocal strain gradient theory. In this model, both stiffness-softening and stiffness-hardening effects are considered for more reliable forced vibration analysis of nanoplates. The present model is based on a vibrating higher order nanoscale plate subjected to transverse uniform dynamic load. Nanopores or nanovoids are incorporated to the model based on a modified rule of mixture. According to t Hamilton’s principle, the formulation of dynamically loaded nanoplate is derived. Applying Galerkin’s method, the resonance frequencies and dynamic deflections are obtained. It is indicated that the forced vibration characteristics of the nanoplate are significantly influenced by the porosities, excitation frequency, nonlocal parameter, strain gradient parameter, material gradation, elastic foundation and dynamic load location.
20
Yeh, Wei Ching, and Tsu Hsiao Chu. "The Influence of Blanking Process by Superimposing Ultrasonic Vibrations." Advanced Materials Research 579 (October 2012): 78–85. http://dx.doi.org/10.4028/www.scientific.net/amr.579.78.
Повний текст джерелаАнотація:
The application of ultrasonic vibrations superimposed on wire drawing, deep drawing, upsetting and rolling has been developed in the literature before. Few attempts have ever been made to develop the application of the ultrasonic vibration to blanking process. This paper reports an investigation into the effects of the superimposed ultrasonic vibrations of the punch during the blanking process by experimental design and response surface methodology. The effects of the ultrasonic vibration on the punch load and edge profile are systematically studied. The results show ultrasonic vibrations can decrease the punch load and improve the quality of edge profile.
21
Fu, Qiang, and Changjie Zheng. "Three-Dimensional Dynamic Analyses of Track-Embankment-Ground System Subjected to High Speed Train Loads." Scientific World Journal 2014 (2014): 1–19. http://dx.doi.org/10.1155/2014/924592.
Повний текст джерелаАнотація:
A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.
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Kamgue Lenwoue, Arnaud, Jingen Deng, Yongcun Feng, Haitao Li, Adefarati Oloruntoba, Naomie Songwe Selabi, Micheal Marembo, and Yuanxiu Sun. "Numerical Investigation of the Influence of the Drill String Vibration Cyclic Loads on the Development of the Wellbore Natural Fracture." Energies 14, no. 7 (April 6, 2021): 2015. http://dx.doi.org/10.3390/en14072015.
Повний текст джерелаАнотація:
Wellbore instability is one of the most serious issues faced in the drilling process. During drilling operations, the cyclic loads applied on the fractured formation progressively modify the initial parameters (i.e., length and width) of the fractured formation, thus resulting into undesirable wellbore instability. In this paper, using a nonlinear finite element software (ABAQUS) as the numerical simulator, a poro-elasto-plastic model has been established which aimed at analyzing the influence of drill string vibration cyclic loads on the development of the wellbore natural fracture. The numerical results showed that the fracture width as a function of time profiles followed a sinusoidal behavior similar to the drill string vibration cyclic load profiles. For different cyclic load magnitudes with constant number of cyclic loads, the highest percentage increase of the fracture width after integration of cyclic loads was 64.77%. Interestingly, the fracture width increased with the fracture length in the near wellbore region while it globally decreased in the region far away from the wellbore. But for constant cyclic load magnitude with different number of cyclic loads, the biggest percentage increase of the fracture width after integration of cyclic loads was slightly lower representing 63.12% while the oscillating period of the fracture width increased with the number of cyclic loads. The parametric study revealed that the drill string vibration cyclic loads were relatively independent of the fracture length and the bottom hole pressure. However, the fracture width and the loss circulation rates were considerably impacted by the drill string vibration and the highest percentage increase of the loss circulation rate after integration of cyclic loads was 14.3%. This study provides an insight into the coupling of the fracture rock development and the continuous cyclic loads generated by drill string vibrations which is an aspect that has been rarely discussed in the literature.
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Shpachuk, V. P., M. A. Zasiadko, T. O. Suprun, and V. V. Dudko. "Variation coefficient of torsional vibrations of the connection nodes of vibrating machines." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 6 (2021): 85–89. http://dx.doi.org/10.33271/nvngu/2021-6/085.
Повний текст джерелаАнотація:
Purpose. To formalize the dependence of the eigenfrequencies of translational and torsional vibrations of the structural elements of the vibrating machine articulated by the connection node on their design parameters and mechanical characteristics, as well as regulatory requirements for vibration activity, strength and accuracy. To develop a method for selecting the design parameters of the elastic band element of the package, taking into account the specified values of the amplitude and frequency characteristics of the dynamic loads reproduced by the supporting structure and the coefficient of variation of the natural frequencies of translational and torsional vibrations. Methodology. The research is based on fundamental approaches of applied mechanics, machine dynamics and vibration reliability. Findings. The dependences of the eigenfrequencies of torsional vibrations of the body parts of the vibrating machine connected by the connection node on their design parameters and mechanical characteristics are obtained and analyzed. Vibrations around an axis orthogonal to the working direction of the node are considered. A comparative analysis of the natural frequencies of the node in the direction of the transmitted vibration and its circular vibrations from the design parameters and mechanical characteristics of the elastic band elements, their number in the package and the number of packages in the connection node is performed. Originality. It is in the fact that for the first time the dependences describing the natural frequencies of translational and torsional vibrations of the body parts of a vibrating machine, articulated by a package of elastic band elements, are obtained. Also the paradigm for the choice of design parameters and mechanical characteristics of the elastic band element of the package, which is based on the results of a comparative analysis of the eigenfrequencies of vibrations in the working and connected directions through their coefficient of variation is innovative. This made it possible to include the criterion of vibration reproduction accuracy, which is formalized through the coefficient of frequency variation, together with the criteria of strength and rigidity, in the methodology of synthesis of the structural scheme of the vibrating machine. Practical value. The proposed methodological solutions for the calculation and selection of design parameters and mechanical characteristics of tape elastic elements ensure the achievement of vibration activity indicators of articulated parts, as well as the ratio of natural vibration frequencies in the working and related directions at the level of the requirements of normative documents when upgrading existing machines and creating new modern equipment. As a result, the reliability, durability, safety, productivity and load-bearing capacity of machines, equipment and mechanisms of mining engineering, aviation, transport and space technology are increased.
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Davis, Toren S., and David A. Osterberg. "Heavy load vibration isolation apparatus." Journal of the Acoustical Society of America 105, no. 4 (1999): 2074. http://dx.doi.org/10.1121/1.426806.
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Jiao, Z., P. Chen, Q. Hua, and S. Wang. "Adaptive vibration active control of fluid pressure pulsations." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 217, no. 4 (June 1, 2003): 311–18. http://dx.doi.org/10.1177/095965180321700407.
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Conventionally, passive hydraulic absorbers are utilized in order to reduce the vibrations of the fluid power supply systems. It is very difficult to adapt the variable operation conditions, such as inconsistent vibration frequency and varying loads. This paper presents a new vibration active control method to diminish the vibrations of the fluid power supply efficiently. This method is adaptive and robust in controlling the fluctuating frequencies and load disturbances and is capable of keeping the vibrations at a minimum level under variable pump speeds. This paper illustrates the theory and experimentation of vibration active control of a fluid power supply pipeline system in detail. The multilayer piezoelectric technology (PZT) driven orifice valve is designed with characteristics of a proportional opening area to the control voltage, a high-frequency bandwidth and small size. The adaptive-optimum control method is adopted to adjust the control parameters at any instant against emerging disturbances. Based on the test rig, different vibration control methods were applied; the results indicate and confirm the validity of this principle.
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Sarankó, Ádám, Róbert Keresztes, and Gábor Kalácska. "New method for dynamic tribological test of engineering polymers." International Journal of Engineering and Management Sciences 3, no. 1 (February 13, 2018): 25–29. http://dx.doi.org/10.21791/ijems.2018.1.4.
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In this article, tribological tests of Polyamide 6 (PA 6), Ultra High Molecular Weight Polyethylene (UHMW PE) and Polyoxymethylene copolymer (POM C) by a new testing method is introduced. The tribometer used in the test is capable for pin-on-disc measuring within all possible layout known in tribology practice, otherwise can be modified into special model of fatigue sliding test. The pin was a specimen made from examined materials, always in contact with a rotating metal disc under a normal load, which is usually static. However, since vibration exists in every practical scene as an important phenomenon, for instance in turning process, we added vibration load into the test. The supplement load is generated by a special-designed vibrating machine. Then properties of examined materials can be studied more profoundly under vibration load. As a result, different value of friction coefficient in static and vibration load have been discovered and taken into comparison.
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Meshcheryakov, Viktor, Tatyana Sinyukova, Alexey Sinyukov, and Oleg Vladimirov. "Analysis of the effectiveness of using the block for limiting the vibrations of the load on the mechanism of movement of the bogie with various control systems." E3S Web of Conferences 220 (2020): 01059. http://dx.doi.org/10.1051/e3sconf/202022001059.
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Damping load vibrations in an electric crane drive is an urgent topic for research. The swinging load has a negative effect on the mechanical part of the device, leading to its wear, and on the entire control system as a whole. To combat the swaying of the load, it is proposed to install a vibration damping block created on the basis of an equation describing the dependence of the change in the deviation of the load on the equilibrium position in the plane of movement of the cart. The control signals in the vibration damping unit are the parameters of truck acceleration, suspension length, and weight of the load. At the output of the vibration damping unit, a speed task is formed. A block diagram of the trolley drive control system has been developed. Both scalar systems and systems with direct torque control are used on trolley travel mechanisms. The paper analyzes the efficiency of using the vibration damping unit when using different control systems on the movement mechanism of the bridge crane trolley.
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Morozov, A. L. "COMBINED SIGNAL PROCESSING METHOD FOR DIAGNOSIS AND MONITORING OF THE INDUCTION MOTORS OPTIMIZED FOR EMBEDDED SYSTEMS." Kontrol'. Diagnostika, no. 280 (October 2021): 18–27. http://dx.doi.org/10.14489/td.2021.10.pp.018-027.
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Induction Motors (IM) play a key role in modern industry, so the condition monitoring systems are becoming increasingly relevant. Commercial monitoring systems are usually based on the measurement of IM’s vibrations and the further processing of the measured vibration signals. For those purposes the embedded systems (such as microcontrollers and inexpensive processors) are used. Embedded systems have limited resources, so data processing algorithms should have low computational complexity and require little memory. In this paper, the wellknown methods of processing vibration signals for fault diagnosis of the IM are considered and their main advantages and disadvantages for the implementation in embedded systems are highlighted. The previously proposed method based on a combination of the fast Fourier transform and the statistics of the fractional moments is optimized for vibration signal processing and implementation in embedded systems. The efficiency of diagnosis of such faults as eccentricity and a broke rotor bar, using the proposed method, is verified on the radial vertical vibrations measurements of the real motors under different constant load levels: no load, 50 % of the rated load, 75% of the rated load. The results show that this approach allows accurately diagnose the considered faults independently from the load level.
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Tsukiboshi, Taisuke, Hajime Sato, Yuto Tanaka, Mitsuru Saito, Hiroki Toyoda, Toshifumi Morimoto, Kemal Sitki Türker, Yoshinobu Maeda, and Youngnam Kang. "Illusion caused by vibration of muscle spindles reveals an involvement of muscle spindle inputs in regulating isometric contraction of masseter muscles." Journal of Neurophysiology 108, no. 9 (November 1, 2012): 2524–33. http://dx.doi.org/10.1152/jn.00997.2011.
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Spindle Ia afferents may be differentially involved in voluntary isometric contraction, depending on the pattern of synaptic connections in spindle reflex pathways. We investigated how isometric contraction of masseter muscles is regulated through the activity of their muscle spindles that contain the largest number of intrafusal fibers among skeletal muscle spindles by examining the effects of vibration of muscle spindles on the voluntary isometric contraction. Subjects were instructed to hold the jaw at resting position by counteracting ramp loads applied on lower molar teeth. In response to the increasing-ramp load, the root mean square (RMS) of masseter EMG activity almost linearly increased under no vibration, while displaying a steep linear increase followed by a slower increase under vibration. The regression line of the relationship between the load and RMS was significantly steeper under vibration than under no vibration, suggesting that the subjects overestimated the ramp load and excessively counteracted it as reflected in the emergence of bite pressure. In response to the decreasing-ramp load applied following the increasing one, the RMS hardly decreased under vibration unlike under no vibration, leading to a generation of bite pressure even after the offset of the negative-ramp load until the vibration was ceased. Thus the subjects overestimated the increasing rate of the load while underestimating the decreasing rate of the load, due to the vibration-induced illusion of jaw opening. These observations suggest that spindle Ia/II inputs play crucial roles both in estimating the load and in controlling the isometric contraction of masseter muscles in the jaw-closed position.
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Rao, D. K., G. V. Brown, P. Lewis, and J. Hurley. "Stiffness of Magnetic Bearings Subjected to Combined Static and Dynamic Loads." Journal of Tribology 114, no. 4 (October 1, 1992): 785–89. http://dx.doi.org/10.1115/1.2920949.
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This paper investigates the stiffness of a magnetic bearing that is subjected to the combined action of static and dynamic loads. Since their sum cannot exceed the saturation load, a large static load will imply that the bearing can carry only a small dynamic load. This smaller dynamic load together with the practical vibration amplitude define a practical upper bound to the dynamic stiffness. This paper also presents approximate design formulas and curves for this stiffness capacity as a function of the ratio of dynamic and static loads. In addition, it indicates that vibrations larger than a certain gap fraction can destabilize the magnetic bearing. This gap fraction, called the critical gap fraction, depends on the dynamic and static load ratio. For example, if the dynamic load is half of the static load, the use of more than 25 percent of gap can destabilize the bearing.
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Choi, S. H., J. Glienicke, D. C. Han, and K. Urlichs. "Dynamic Gear Loads Due to Coupled Lateral, Torsional and Axial Vibrations in a Helical Geared System." Journal of Vibration and Acoustics 121, no. 2 (April 1, 1999): 141–48. http://dx.doi.org/10.1115/1.2893956.
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In this paper we investigate the rotordynamics of a geared system with coupled lateral, torsional and axial vibrations, with a view toward understanding the severe vibration problems that occurred on a 28-MW turboset consisting of steam turbine, double helical gear and generator. The new dynamic model of the shaft line was based on the most accurate simulation of the static shaft lines, which are influenced by variable steam forces and load-dependent gear forces. The gear forces determine the static shaft position in the bearing shell. Each speed and load condition results in a new static bending line which defines the boundary condition for the dynamic vibration calculation of the coupled lateral, torsional and axial systems. Rigid disks and distributed springs were used for shaft line modeling. The tooth contact was modeled by distributed springs acting normally on the flank surfaces of both helices. A finite element method with distributed mass was used for lateral and torsional vibrations. It was coupled to a lumped mass model describing the axial vibrations. The forced vibrations due to unbalances and static transmission errors were calculated. The eigenvalue problem was solved by means of a stability analysis showing the special behavior of the coupled system examined. The calculation was successfully applied, and the source of the vibration problem could be located as being a gear-related transmission error. Several redesign proposals lead to a reliable and satisfactory vibrational behavior of the turboset.
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Kim, Young Moon, Ki Pyo You, and Jang Youl You. "Active Control of Along-Wind Response of a Tall Building with AMD Using LQR Controller." Applied Mechanics and Materials 490-491 (January 2014): 1063–67. http://dx.doi.org/10.4028/www.scientific.net/amm.490-491.1063.
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Most of modern tall buildings using lighter construction materials are more flexible so could be excessive wind-induced vibrations resulting in occupant discomfort and structural unsafety. The optimal control technique for reducing along-wind vibration of a tall building based on the linear quadratic regulator (LQR) is presented in this work. Actively controlled reduced along-wind vibration response is obtained from the tall building installed in an active mass damper (AMD) with a LQR controller. Fluctuating along-wind load is generated using numerical simulation method, which can formulate a stationary Gaussian white noise process. Simulating wind load in the time domain using known spectra data of fluctuating along-wind load is particularly useful for estimation of windinduced vibration which is more or less narrow banded process such as a along-wind response of a tall building. In this work, fluctuating along-wind load acting on a tall building treated as a stationary Gaussian white noise process is simulated numerically using the along-wind load spectra proposed by G. Solari in1992. And using this simulated along-wind load estimated the reduced along-wind vibration response of a tall building installed in an AMD with a LQR controller.
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Anigbogu, Winner, and Hamzeh Bardaweel. "A Metamaterial-Inspired Structure for Simultaneous Vibration Attenuation and Energy Harvesting." Shock and Vibration 2020 (June 13, 2020): 1–12. http://dx.doi.org/10.1155/2020/4063025.
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In this article, a magnetomechanical metamaterial structure capable of simultaneous vibration attenuation and energy harvesting is presented. The structure consists of periodically arranged local resonators combining cantilever beams and permanent magnet-coil systems. A prototype of the metamaterial dual-function structure is fabricated, and models are developed. Results show good agreement between model simulation and experiment. Two frequency bandgaps are measured: 205–257 Hz and 587–639 Hz. Within these bandgaps, vibrations are completely attenuated. The level of vibration attenuation in the first bandgap is substantially larger than the level of vibration attenuation observed in the second bandgap. Mode shapes suggest that bending deformations experienced by the local resonators in the second bandgap are less than the deformations experienced in the first bandgap, and most vibrational energy is localized within the first bandgap where the fundamental resonant frequency is located, i.e., 224 Hz. The ability of the fabricated metamaterial structure to harvest electric power in these bandgaps is examined. Results show that vibration attenuation and energy harvesting characteristics of the metamaterial structure are coupled. Stronger vibration attenuation within the first bandgap has led to enhanced energy harvesting capabilities within this bandgap. Power measurements at optimum load resistance of 15 Ω reveal that maximum power generated within the first bandgap reaches 5.2 µW at 245 Hz. Compared with state-of-the-art, the metamaterial structure presented here shows a significant improvement in electric power generation, at considerably lower load resistance, while maintaining the ability to attenuate undesired vibrations within the frequency bandgap.
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Abd Alsamieh, Mohamed. "Numerical investigation of elastohydrodynamic contacts subjected to harmonic load variation." Industrial Lubrication and Tribology 71, no. 6 (August 12, 2019): 832–41. http://dx.doi.org/10.1108/ilt-12-2018-0461.
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Purpose The purpose of this paper is to study the behavior of elastohydrodynamic contacts subjected to forced harmonic vibrations including the effect of changing various working parameters such as frequency, load amplitude and entrainment speed. Design/methodology/approach The time-dependent Reynolds equation is solved using the Newton–Raphson technique. The film thickness and pressure distribution are obtained at every time step by simultaneous solution of the Reynolds equation and film thickness equation including elastic deformation. Findings The frequency of vibration, load amplitude and entrainment speed are directly related to the film thickness perturbation, which is formed during load increasing phase of the cycle. The film thickness formed during load increasing phase is larger than that formed during load decreasing phase with larger deviation at a higher frequency or load amplitude and vice versa for lower frequency or load amplitude. The entrainment speed of the contact has an opposite effect to that of the frequency of vibration or load amplitude. Originality/value Physical explanations for the behavior of elastohydrodynamic contact subjected to forced harmonic vibration are presented in this paper for various working parameters of frequency, load amplitude and entrainment speed.
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Fleming, David P. "Dual Clearance Squeeze Film Damper for High Load Conditions." Journal of Tribology 107, no. 2 (April 1, 1985): 274–78. http://dx.doi.org/10.1115/1.3261045.
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Squeeze film dampers are widely used to control vibrations in aircraft turbine engines and other rotating machinery. However, if shaft unbalance rises appreciably above the design value (e.g., due to a turbine blade loss), a conventional squeeze film will be overloaded, and will no longer be effective in controlling vibration amplitudes and bearing forces. This paper describes a new damper concept characterized by two oil films. Under normal conditions, only one low-clearance film is active, allowing precise location of the shaft centerline. Under high unbalance conditions, both films are active, controlling shaft vibration in a near-optimum manner, and allowing continued operation until a safe shutdown can be made.
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Yang, Chao, Yansong Wang, Hui Guo, Jiang Lv, Ningning Liu, and Hongzhong Qi. "Vibration load and transfer path identification of vehicle using inverse matrix method based on singular value decomposition." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 6 (November 22, 2019): 1703–13. http://dx.doi.org/10.1177/0954407019887887.
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Based on the theory of inverse transfer matrix, a novel method for simultaneous load identification of vehicle vibration is presented in this paper. Some response, excitation, reference points (called key points) and their transfer paths, which have severe effects on the vibration of a whole vehicle, are defined. The transfer functions among the key points are measured by experiments, and thereby a transfer function matrix of vehicle vibration is established. To solve ill-conditioning problem in the transfer function matrix, the methodology of singular value decomposition is introduced into matrix inversion in the excitation load identification. To reduce the identification error, four transfer function matrices with different reference points and condition numbers are selected and discussed. The results show that the more the reference points are, the smaller the condition number of transfer function matrix is, the higher the accuracy of excitation load identification. The transfer function matrix with minimum condition number is used to identify the excitation loads at the vehicle key points. Experimental verifications suggest that the newly proposed method is effective and feasible for excitation load identification of vehicle vibration. Using the identified excitation loads, furthermore, the vibration causes of the steering wheel and seat rail are obtained, which is helpful for improving vibration performance of the sample vehicle. In applications, the excitation load identification method proposed in this paper may be applied not only to other types of vehicle, but also to other complex electromechanical products for load identification in engineering.
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Muhlisin, Iip, and Rusman Rusyadi. "Vibration Analysis on Rotating Machines using Fast Fourier Transform (FFT)." ACMIT Proceedings 3, no. 1 (March 18, 2019): 67–75. http://dx.doi.org/10.33555/acmit.v3i1.28.
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The history has record that heavy industries face major problems that causes by variant types of mechanical failures came from rotating machines. The Vibrations in rotating machine almost fond in everywhere, due to unbalances, misalignments and imperfect part, analytical approaches has shown that vibration monitoring has great capability in detecting and addressing the defect particular part in the machine line .The vibration velocities and vibration load will be measured at different speeds using The Time-frequency analysis at initial condition. The result of vibration readings spectrum analysis and phase analysis can be determining the figure of vibrations character, and the causes of height vibration will be found. By reading the spectrum unbalance will be identified. When the unbalanced part was balanced then we found that the vibration was decrease. The Vibration experimental frequency spectrum test will be conduct for both balanced and unbalanced condition and also in different speed conditions. To full fill the vibration analysis test, in this experimental research a prototype of vibration monitoring system was constructed. The vibration can be generated and the system performance can be monitored. In this prototype the signal from load cell and velocity sensor will be processed in microcontroller and send to computer where FFT will processed the signal to create spectrum in the computer display. The actual final result of Vibration analysis test will be provide after finish the vibrations analysis test that will be done latter, therefore the chart result on this paper is based on theoretical only.
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Qiao, Yu Lin, Shan Lin Yang, Yan Zang, and Dong Wang. "Effect of Ultrasonic Vibration on Friction and Wear Properties of GCr15/45# Steel Frictional Pairs under Oil Lubrication." Advanced Materials Research 295-297 (July 2011): 2102–5. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.2102.
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Ultrasonic vibration friction and wear experiments were carried out by MFT-R4000 reciprocating friction and wear tester bonded with ultrasonic device. The surface morphologies of wear scars were examined by scanning electron microscope (SEM). The influences of ultrasonic vibration on friction reduction and anti-wear properties of GCr15/45# steel frictional pairs under different loads were discussed. The experimental results showed that, the friction of GCr15/45# steel frictional pairs could be reduced by ultrasonic vibration, and the reduction of friction coefficient became more obvious as the loads increasing. The friction coefficient measured under ultrasonic vibration is 12% lower than it measured without ultrasonic vibration when the load was 50N. However, the wear of frictional pairs increased under ultrasonic vibration, and the amplitude of wear volume enlarged with the loads increase, which is 63% at the load of 50N.
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Wan, Jian. "An Analysis on the Effect of External Shock Loads on Building Structure Vibration." Applied Mechanics and Materials 513-517 (February 2014): 4135–38. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.4135.
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This paper studies how the external shock loads induces vibration, and proposes a method to analyze the effect of external shock loads on building structure vibration. On basis of elastic mechanics and dynamics theory, the method calculates pressure load on each bearing node of the building produced by finite element model in accordance with the nodal displacement equivalent principle, and takes the load as excitation to study vibration of the building structure. The accuracy of the analytical method is verified by comparing with classical theory and the analysis' results of other scholars. Experiments show that the vibration analysis model can efficiently perform analysis of vibration induced by uncoupled external shock for building with complex spatial structure.
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Li, Zhang Ming, and Wen Xiu Zeng. "Vibration Propagation Law and Control Test of Ultra Soft Soil Ground under Impact Load." Applied Mechanics and Materials 295-298 (February 2013): 2030–33. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.2030.
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Through in situ tests on the impact vibration of a typical muck ground treatment major project directed by the first author, the vibration propagation law under the impact load for the ultra soft soil ground is obtained, and quantitative environmental safe control distance on the vibration influence is also gained. The main results are the two aspects. (1) The attenuation law of both level and vertical peak vibration acceleration with the horizontal distance can be described well by the negative power function; and the ground vibrations caused by tamping impact can be distinguished between two types, i.e. near-field and far-field. Near-field tamping vibration influence is confined to a small range of the tamping center, which decays obviously faster than the one of far-field. (2) The radius of influence of tamping vibration depends not only on the tamping energy but also the soil type. Loose, slightly dense soft soil has a larger energy absorption capacity and a smaller effect radius of tamping vibration than the dense and hard soil; and the vibration safe control distance is determined as 27.3m in the tests according to the safe boundary determined code of industrial and civil architecture in China.
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Tang, Chuxuan, Zheng Lu, Hailin Yao, Shuan Guo, and Yukun Han. "Vibration Characteristics of Unsaturated Runways Under Moving Aircraft Loads." International Journal of Structural Stability and Dynamics 21, no. 05 (February 16, 2021): 2150065. http://dx.doi.org/10.1142/s0219455421500656.
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The dynamic vibrations of airport runways induced by moving aircraft loads are semi-analytically studied in this paper. The airport runway consists of an infinite Kirchhoff plate, an elastic base course, and an unsaturated poroelastic half-space. The aircraft loads are modeled according to the mechanical properties of the main landing gear of the A380 civil airliner. The governing equations of the whole system are solved in the wavenumber domain using the double Fourier transform. Then the results in the spatial domain are obtained by applying the inverse double Fourier transform. Various parameters including the observation location, soil saturation, load speed, load frequency, and pavement rigidity on the vibration characters of the whole system are investigated. It is found that all these effects are crucial, and the increase of soil saturation leads to a larger maximum vertical displacement and lower critical speed.
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Jun, Zhang, Ming Kang Gou, and Chuan Liang. "Experimental Simulation of Bridges Subjected by Moving Loads." Applied Mechanics and Materials 873 (November 2017): 208–11. http://dx.doi.org/10.4028/www.scientific.net/amm.873.208.
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The effect of bridge vibrationinduced bylive loads such as vehicles and pedestrians is an important factor of bridge fatigue damage. It takes much labor and material resource to perform vibration experiments on bridges subjected by real moving loads in field. In order to carry out laboratory experiments on bridges subjected by moving loads, a fixed load with harmonic vibration simulates a moving load on bridge in the beam theory. A simply supported bridge is considered in the present study. The dynamic responses of bridge under different loads are established by the analytic method. Amplitude and frequency of the simulated load are generated on the principle of equal displacements due to both a moving load and a fixed harmonic load impacting on a simply supported beam. Comparisons of numerical results of two types of load on the same beam indicate that the harmonic load can simulate a moving load effectively. It is possible that the field test on bridge can be carried out indoors.
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Chang, Chao-Cheng, and Sin-Siang Huang. "Study on micro nosing process assisted by ultrasonic vibration." MATEC Web of Conferences 185 (2018): 00005. http://dx.doi.org/10.1051/matecconf/201818500005.
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This study used experiments to investigate the effect of ultrasonic vibration on the micro nosing process of copper cup. The billets with 1 mm diameter and length were backwards extruded to form the cups with 0.1 mm wall thickness and 1.8 mm height. The cups were then used in micro nosing processes. A forming system with the ultrasonic vibration has been developed and installed on a precision press to conduct the experiments. An optical fibre sensor and a precession load cell were equipped on the ram of the press in order to accurately measure the load and stroke of the process. Two forming conditions with and without ultrasonic vibrations of 20 kHz were considered in this study. The results show that the ultrasonic vibration can improve the materials flow which leads to an even diameter along the shrunk region of the nosed cup. Moreover, the ultrasonic vibration greatly reduces the load in the micro nosing process of the copper cup.
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Swiatkowski, Michal, and Pawel Witczak. "Analysis of vibration forces of magnetic origin acting on tank walls of power transformer." International Journal of Applied Electromagnetics and Mechanics 67, no. 1 (September 2, 2021): 35–45. http://dx.doi.org/10.3233/jae-201622.
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The aim of this paper is to present the impact of the leakage flux on magnetic shunts and tank walls of power transformers from vibrational point of view. The experimental studies of the large power transformers show that tank vibrations and the resulting acoustic emission at load condition are significantly higher than at no-load condition. The paper presents 3D finite elements model in electromagnetic domain used for the analysis of magnetic forces applied to shunts at rated short circuit state which are the origin of tank vibration. The main finding of the work is that forces equivalent to the magnetostriction deformation of the shunt interior are comparable with magnetic forces resulting from the stray field and applied to the shunts’ surface.
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Rejab, Mohd Noor Arib, Roslan Abd Rahman, Raja Ishak Raja Hamzah, Jawaid Iqbal Inayat Hussain, Nazirah Ahmad, and Asyraf Ismail. "Measurement of Noise inside the Compartment and Vibration on both Sides of Elastomeric Powertrain Mounts of Passenger Car." Applied Mechanics and Materials 471 (December 2013): 59–63. http://dx.doi.org/10.4028/www.scientific.net/amm.471.59.
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This paper presents an evaluation on elastomeric mount used to isolate vibration from powertrain to chassis or structure vehicle. The assessments started with measurement of noise inside compartment, and exhaust noise. This is followed by the measurement of vibration on both sides of elastomeric mounts. The noise in the compartment and exhaust noise is measured according to BS 6086: 1981 and BS ISO 5130: 2007. The noise in the compartment and vibration is tested in three conditions. Firstly, engine is run-up with load (driving at second gear); secondly, without load; and thirdly, without load but hanging. A microphone is fixed at the ear of the mannequin. The fast response and A weighting sound level meter were used for measurement noise in the compartment and exhaust noise. The vibration is measured in terms of acceleration on both sides of each elastomeric powertrain mounts. Two accelerometer transducers are fixed on both sides of powertrain elastomeric mounts. One side was identified as a source of vibration and the other as receiver of vibrations. The results showed that the pattern of overall vibration level on source and receiver increased from 1050 RPM (idling) to 4000 RPM on all test conditions. Vibration transmitted to chassis or receiver structure was analyzed using transmissibility concept. By evaluating test condition of engine run-up without load, informed that the front and rear mounts showed a high level transmissibility contributing to structure-borne noise.
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Li, Dong, Zhou-Lian Zheng, Rui Yang, and Peng Zhang. "Analytical Solutions for Stochastic Vibration of Orthotropic Membrane under Random Impact Load." Materials 11, no. 7 (July 18, 2018): 1231. http://dx.doi.org/10.3390/ma11071231.
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Orthotropic membrane materials have been applied in the numerous fields, such as civil engineering, space and aeronautics, and mechanical engineering, among others. During their serving lifespan, these membranes are always facing strong stochastic vibrations induced by the random impact load such as hail, heavy rain, and noise, among others. In this paper, the stochastic vibration problem of orthotropic membrane subjected to random impact load is investigated. The statistical characteristics of random impact load are initially obtained based on the stochastic pulse theory. Then, the Von Karman theory is applied to model the nonlinear vibration of membrane with geometric nonlinearity, which is then used to derive and solve the corresponding fokker–plank–kolmogorov (FPK). The theoretical model developed is validated by means of experiment study and monte carlo simulation (MCS) analysis. The effects of variables like pretension force, velocity of impact load, and material features on stochastic dynamic behavior of membranes are discussed in detail. This exposition provides theoretical framework for stochastic vibration control and design of membranes subjected to random dynamic load.
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Yang, Wei Guo, and Yao Feng Wang. "Program for the Analysis of Wind-Induced Vibration of Steel Roof Structures." Advanced Materials Research 284-286 (July 2011): 517–22. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.517.
Повний текст джерелаАнотація:
Wind loads are key considerations in the structural design of steel roof structures, especially for large span ones. The analysis of wind loads on large span steel roof structure (LSSRS) requires large amounts of calculations. Due to combined effects of horizontal and vertical winds, the wind induced vibrations of LSSRS are analyzed with the frequency domain method as the first application of the method for the analysis of wind responses of LSSRS. A program is developed to analyze the wind-induced vibrations due to a combination of wind vibration modes. The program, which predicts the wind vibration coefficient and wind pressure acting on the LSSRS, is designed with input and output interfaces to other finite element software, resulting in preferably solving the wind load analytical problem in the design of LSSRS. The effectiveness and accuracy of the proposed method and the program are verified by numerical analyses of practical projects.
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Yang, Zhou, Xue-Ping Li, Jun Li, Tian-Sheng Hong, and Kun-Peng Xue. "Transversal Vibration of Chain Ropeway System Having Support Boundary Conditions with Polygonal Action." Shock and Vibration 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/370248.
Повний текст джерелаАнотація:
The purpose of this paper is to characterize the modal parameters and transverse vibrations of a monochain ropeway system for hilly orchards. The moving chain is modeled with uniform distribution and concentrated inertial loads. In order to study the dynamical behavior of the moving chain, Hamilton’s principle is applied to obtain the homogenous differential equation of transverse vibration. With the boundary conditions subjected to the polygonal action caused by chain-support engagement, the coupling effect of concentrated load, variable tension, and time-dependent speed on transverse vibration is investigated. The contribution of residue of singularity to total vibrations in phase space is numerically analyzed by using the Laplace transform method. The influence of the boundary condition considering the polygonal action is investigated in terms of excitation frequency and amplitude coupled with transport speed. The transverse vibrations are calculated numerically and measured experimentally. The numerical results are in agreement with the experimental data, which suggest that the amplitude and frequency of vibration are proportional to the value of propagation speed. The analytical solution to the moving chain problem provides a feasible reference for its stability analysis and wind-induced vibration control.
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Aoki, Shigeru, and Toshiyasu Nishimura. "Prevention of Delamination during Drilling of Composite Material Using Vibration." Key Engineering Materials 261-263 (April 2004): 381–86. http://dx.doi.org/10.4028/www.scientific.net/kem.261-263.381.
Повний текст джерелаАнотація:
Prevention method of delamination at adhesive layer during drilling of composite material using vibration is examined. First, this method is examined experimentally. As vibrational load, relatively low frequency vibration and ultrasonic vibration are used. It is concluded occurrence of delamination is less when vibration is used during drilling. Next, experimental results are examined by analytical method. Adhesive layer is assumed to be damping component. Condition of occurrence of delamination is proposed.
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Alışverişçi, G. Füsun. "The Nonlinear Behavior of Vibrational Conveyers with Single-Mass Crank-and-Rod Exciters." Mathematical Problems in Engineering 2012 (2012): 1–17. http://dx.doi.org/10.1155/2012/534189.
Повний текст джерелаАнотація:
The single-mass, crank-and-rod exciters vibrational conveyers have a trough supported on elastic stands which are rigidly fastened to the trough and a supporting frame. The trough is oscillated by a common crank drive. This vibration causes the load to move forward and upward. The moving loads jump periodically and move forward with relatively small vibration. The movement is strictly related to vibrational parameters. This is applicable in laboratory conditions in the industry which accommodate a few grams of loads, up to those that accommodate tons of loading capacity. In this study I explore the transitional behavior across resonance, during the starting of a single degree of freedom vibratory system excited by crank-and-rod. A loaded vibratory conveyor is more safe to start than an empty one. Vibrational conveyers with cubic nonlinear spring and ideal vibration exciter have been analyzed analytically for primary and secondary resonance by the Method of Multiple Scales, and numerically. The approximate analytical results obtained in this study have been compared with the numerical results and have been found to be well matched.