In order to complete the literature review, a relevant written documents should be search. It could be found in books, journal articles, newspaper articles, historical records, government reports, theses, project papers and any kind of sources. This study and research information are based on some major component and topics that related to this project. From that, every theory and information about it is compared among it and summarise it as well as critically analysed these documents. The best and most suitable information will be selected to use in this project.
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Another type of resonant microgenerator is described by Mizuno and Chetwynd . Their proposed device comprises a beam with an integrated coil and a fixed external magnet. The dimensions of the cantilever beam were 500 µm × 100 µm × 20 µm and the size of the NdFeB magnet was 30 mm × 10 mm × 6 mm. The resonant frequency of the structure was 58 kHz. A power output of only 6 nW was predicted for a typical single-element electromagnetic microgenerator. The magnitude of the output voltage was estimated as being only 1.4 mV. The authors fabricated a larger version of their proposed device for evaluation purposes. The actual size of the beam was increased to 25 mm × 10 mm × 1 mm and the resulting resonant frequency was 700 Hz. For an input vibration of 0.64 µm, the output power was found to be 0.4 nW. As a result of the low output power, the authors suggest that electromagnetic generators do not offer practical solutions for energy harvesting problems. They may have reached a different conclusion if they had chosen to evaluate a moving- magnet approach as the additional seismic mass would have increased the electrical power available.
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The transient nature of force induced in bridges during vehicular motion requires dynamic analyses of the spectrum of a sensed vibration signal to fully characterize their behavior. This dynamic interaction between the vehicle and bridge induces a vibration in the bridge and this degree of vibrations in the bridge can be sensed using an optical fiber while the spectrum of the vibrations is measured using an Optical Time Domain Reflectometer(OTDR). The OTDR trace shows the various degrees of attenuations across the optical fiber cable. Useful information such as the location of vibration, the severity of vibration, vibration frequency and the vibration modes can be successfully modeled from the recorded OTDR traces. This work focused on measurements and analysis of loss associated with vibration and hence a statistical determination of the vibration severity concerning the dynamic interaction time between the optical fiber and the traversing vehicle as captured on a time series video clip.
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The bearing unit is multi-parameter system and its life is influenced by many parameters. The mentioned research analyses did not involve inaccuracy (dimensional and geometrical) of shafts as a source of larger vibrations and noise resulting in the reduction of bearing life. Our research has been focused on the impact of shaft accuracy on bearing life. The paper focused on dimensional and geometrical inaccuracies that highly modify the bearing life. Moreover, the paper provides the results obtained in the flexoprinting machine where the needle rolling bearings were mounted focusing on radial bearing clearance and related vibrations. The vibration measuring draw connection between the size of the vibration and the accuracy of the bearing shaft, upon which the bearing mounted.
Ambient vibration sources are divided into free vibration and forces vibration. All sources collectedusing highly sensitive acceleration device sensor such as seismometer and accelerometer. Seismometer collected ambient vibration from free vibration sources, whereas accelerometer collected ambient vibration from both free and forces vibration sources. Generally it was accepted that seismometer are more reliable to record ambient vibration. Advantages of free vibration sources is the sources represent the actual operating conditions of the structure which vibrates under its natural excitation loads such as traffic, winds, and microtremors . This paper is focusing on ambient vibrationtest from free vibration sources using seismometer sensor.
Engine and cutting structure are the main vibration sources of crawler-type combine harvester (Polin et al., 2014). The cutting structure of the crawler-type combine harvester belongs to the support cutting, the fixed blade is stable, but the moving blade is cut at a certain speed, and the speed of the cutter’s motion directly affects the cutting quality. As the moving blade travels in the reciprocating motion, it is bound to have a constant change of acceleration, and the structure is made up of components with a certain mass, which is bound to produce the inertia force of the reciprocating motion (Amponsah et al., 2017). The inertia force acts on the cutting platform and causes the continuous vibration of the cutting platform. Although the mass of the cutting platform can absorb part of the vibration, the vibration of the cutting platform is still serious (Ahamed et al., 2017; Roy et al., 2018; Zhang et al., 2018). In view of the above problems, the method of increasing the balance weight should be adopted to reduce the vibration degree, reduce the wear and brittle fracture of parts caused by the vibration, and improve the mechanical reliability and the working quality (Dong et al., 2017). The key to solve this problem is to determine the size and orientation of counterweight, and do dynamic research on the transmission system of cutter. For the vibration problem of the harvester engine, the vibration model for the engine system of the combine harvester is set up, the vibration theory is designed and the damping pad is selected to reduce the vibration effect produced by the engine (Daya and Pant, 2017)
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Excessive vibration in engineering systems are generally undesirable and therefore avoided for the sake of safety and comfort. Vibration has been known as the factor of disturbance, discomfort, damage and destruction. It could also lead to excessive deflections and failure on the machines and structures. Exposure to vibration for a long period also can be harmful where it causes disease and muscular-skeletal pain. Thus, vibration needs to be eliminated with the effective ways to prevent all the bad effects. It is possible to reduce untoward amplitudes by attaching to the main vibrating system an auxiliary oscillating system. Therefore, this study was undertaken to reduce the risk stated by producing a new design of dynamic vibration absorber (DVA) attached to a structure called fixed-fixed end beam.
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Abstract: In recent trends the industries are transforming from preventive maintenance to predictive maintenance. It essentially involves human sensory with mixture of sophisticated instruments to inspect the machines while running. Vibration analysis is the one of the most effective tool used to check the health of plant machinery and diagnose the causes. The health of machine is checked by routine or continuous vibration monitoring with sophisticated instruments, which will give you early indication of the failure and can take countermeasures to avoid catastrophic failure.In this thesis work I have studied the common causes that produce vibrations in rotating machines. Every machinery problem produces specific spectrum pattern, these problems are identified with frequency and phase analysis. Here I have explained in details about frequency analysis, phase analysis, unbalancing and procedure of Balancing. Also the vibration measurement and data collection equipments as well as acceptance standards are discussed. The different case studies that I carried out at different industries contains the Balancing problems, misalignment issues and Resonance, which we removed by Balancing, alignment across coupling and dynamic vibration absorbers. In one of the case study we made the decision for location of CMM machine through vibration analysis.
The “crowding” term has been proven to be challenging because it has multiple meanings and has been inconsistently defined (Mohd Mahudin, Cox and Griffiths, 2012). The duration of travelling is depending on the destination of the moving train users. For this project research will be focus on Keretapi Tanah Melayu Berhad (KTMB) commuter users. This project research is proposed to investigate the risk factor that contribute to discomfort feeling that were develop when in prolonged stand position and vibration rates experienced by the train’s passenger while in the moving train.
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Abstract: This study investigates experimentally the relationship between induced vibration and surface roughness in turning of 41Cr4 Alloy steel using Response Surface Methodology RSM. The levels of process cutting parameters in the study are limited to the following data; Depth of cut (1.0, 2.0, 3.0 mm), cutting speed (260, 320, 400 rpm), feed rate (0.15, 0.20, 0.30 mm/rev), tool nose radius (0, 1, 2 mm), tool overhang (50, 55, 60 mm) and work piece overhang (80, 100, 120 mm). The data are generated by lathe turning of 41Cr4 Alloy steel samples at different levels of low, medium and high. From the study it shows that Induced vibration has a significant effect on surface roughness of work piece. The surface roughness of work piece is proportional to cutting tool acceleration. This effect interacts with other independent variables such as depth of cut, cutting speed and cutting tool overhang etc. Experimental results have shown that induced vibration has significant impact on surface roughness which can be used to control the finished surface of a work pieces during mass production.
The defects of the gear will happen eventually after a long operational time. However, the lifespan of the gears can be prolonging by eliminating the sources of defects such as imbalanced of the rotating parts, misalignment of the shaft and others. The examples of gear defect which usually can be seen on the gears tooth are pitting, scuffing, spalling, scoring and etcetera. These defects are basically are a result of repeated surface or rub-surface stresses during gear meshing that goes beyond the endurance limit of the materials that caused surface fatigue. These defects will cause the vibration level in the system to rises and exceeding the normal vibration level. The defect on certain gears can be detected using several methods such as visual and sound inspection, however, the analysis on the lubricant used and vibration analysis is proven to give out better result.
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In this section the time-period responses are related to the time-period vibration lev- els. Table 1 shows the results from the ordinal logit model parameter estimations. These results are used to calculate the estimated exposure-response relationship in Equation (1). For example, to calculate the proportion of respondents who are esti- mated to be annoyed by a VDV b of 0.01 m/s 1.75 during the day, the estimated param-
As for noise, an increase in the magnitude of vibration leads to an increase in reported annoyance [3–5,33]. Standards in this area focus on objective vibration exposure and variables that affect it, such as magnitude, duration and proximity. Physical descriptors of the vibration, e.g., frequency and duration, as well as accompanying noise also correlate with annoyance from vibrations [34,35]. Waddington et al.  assess sixty different vibration descriptors and six frequency weightings for how well they predict annoyance. It is found that no one descriptor is particularly better, but that frequency weighting is important for increasing the correlation between exposure and response. Fields and Walker  describe that in the absence of vibration measurements, distance, and therefore magnitude, is related to the reports of vibration in people’s homes, but that other factors are important. The Spearman correlation coefficient between a range of exposure predictors and annoyance is found  to be low, suggesting that other factors are important. For annoyance from rail-related vibration, it is found that only a quarter of the variance in reported annoyance can be accounted for by the exposure-response relationship . Schomer and Neathammer  find that rattling, as a result of ground-borne vibration, can bias annoyance by 12 dB. Woodroof and Griffin  conclude that rather than the magnitude of vibration from railways, it is the number of trains per 24-h period that correlates with annoyance. Similarly Gidlof et al.  find that annoyance from railway vibration is increased in the presence of railway noise and vice versa. Gidlof et al.  also look at train-related factors affecting annoyance, specifically the number of trains and the presence of ground-borne vibration. It is found that there is an increase in annoyance for higher vibration velocities. There is a large interaction between vibration and noise in causing annoyance.
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Osteoporosis is a bone disease characterized by the loss of bone mineral density (BMD). As a result, individuals suffering from this disease are highly susceptible to bone fractures, even from a relatively minor trauma such a fall. With an increasingly ageing population, the financial burden on the healthcare system of treating osteoporosis will continue to rise. One potential non-pharmacological treatment for reversing and preventing osteoporosis is the use of low-level mechanical stimulation to stimulate bone growth. 1,2 This treatment is based on the principle of Wolff's law, 3 which states that the bones of human and animal are constantly adapting to its local mechanical environment such as pressure, shear stress, and strain. Consequently, bone is constantly remodeled itself resulting in increased or decreased BMD, depending on the mechanical requirements of its local environment. One dramatic manifestation of Wolff’s Law is the case of astronauts in space, 4 where their BMD decreases significantly due to lack of mechanical stimulation and decreased load bearing in a micro-gravity environment. One way of introducing mechanical stimulation to the body is the whole-body vibration (WBV), which applies a carefully controlled mechanical vibration to the entire body of a human or animal through the feet. Many positive effects of WBV have been reported, both in human studies 5-9 and animal studies. 10-14
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ANSYS and MATLAB software are fully utilised in the FEM to analyse modal and transient analysis by using main menu command, ‘pre-processing’>‘solution’>‘post processing’>‘time history post processing’. In ANSYS, every element is assigned with material constant to define structure properties in term of density, poison ratio and modulus of elasticity. All elements are design in homogeneous and isotropic under BEAM4 and SHELL63 for elastic concrete structure such as beam, column and slab. Then structure is meshed under suitable mesh size and set up the boundary condition on ground floor column to be fixed structure. Then the structure is solved to run modal analysis by Block Lanczos method which is suitable for complicated 3D structure. By taking Fig. 2 Generic vibration criteria (VC) curve
The study respondents self-assessed their degree of overall annoyance and their degree of annoyance during particular times the of day due to railway vibration on a five- point semantic scale, as recommended by the standard ISO/TS 15666 (2003) (Condie et al., 2009). In the survey, annoyance during different time periods was assessed, from respondents who stated being somehow annoyed by vibration, and through the follow- ing question: “Thinking about the last 12 months or so, when indoors at home, how bothered, annoyed, or disturbed have you been by feeling vibration or hearing or
In 2010 American scholars studied a kind of portable vortex induced vibration generator , as shown in Figure 7. Cylindrical body produced vortex induced vibration under the action of wind, accordingly the piezoelectric ball vibrated and induced deformation, thus generated electric energy. The size of the gene- rator was 20 mm × 20 mm × 255 mm. The power was 20 µW at the wind speed 1 - 3 m/s.
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This paper presents a study on the effect of vibration source and TMD distance from the center of gravity (COG) to the vibration responses of a 2DOF main system. The system was mathematically modeled and simulated. The simulation results were verified experimentally and analyzed. The valid model was used to simulate the vibartion responses and vibration reduction of the 2DOF main system due to variation of the vibration source distance and TMD distance from the COG. METHOD
The vibration transmitted to the hand arm system due to hand held tools is one of the major aspects in designing the hand held tools. The vibration transmitted are measured in terms of biodynamic response viz. by driving point mechanical impedance (DPMI), absorbed power, apparent mass, force recall method, subjective ratings of intensity and discomfort etc. The characteristics of the hand driving point mechanical impedance distributed at the fingers and the palm are very different. The characteristics suggests that the vibration power absorption measured at the fingers may be a better measure than the total vibration power absorption of the entire HAS for studying the vibration induced finger disorders; and the palm MI may have a better association with the injuries in the palm wrist arm structures Dong et. al. (2005).
Figure 12 details the result of Gaussian mixture modeling within a contour plot for the Z-axis component from the generator vibration sensor trended against generator rotor speed, separated into the four operating regions. Within this plot, outwardly lines represent areas of decreasing probability. These plots revealed this method works well for regions 2, 3 and 4, where contour lines fit tightly around clear groups of data. However, this technique is not as effective for region 1, where data points are spread more sparsely throughout the plot.
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