Experimental Analysis of Balance-Induced Vibrations in Vehicle Shafts

Centrifugal pumps are widely used in industry and also domestically. It is commonly used for its robust design and its efficiency. Every machine has to be monitored periodically in order to maintain its efficiency and also to avoid unexpected failure which lead to loss of efficiency. So fault diagnosis is necessary to monitor the pump periodically for finding out the defects in pump and to replace it if necessary. Dismantling and assembling of pumps during fault diagnosis is a tedious process, vibration analysis can be helpful to monitor the performance of the pump system without dismantling. For the experimentation purpose mono-block centrifugal pumps have been used in this work. By using the Lab VIEW program and DAQ card as an interface, amplitude and frequency of vibration is obtained at different axes of the pump with the help of an accelerometer. Then the vibration spectrum is analyzed and defects are pointed out by identifying the frequency at which the amplitude of vibration is above the danger limit. The defects such as unbalance of impeller, bent shaft in pump, misalignment of shaft, hydraulic pulsation, cavitation and bearing defects are diagnosed using vibration data. The frequency at which different defects are occurring has been founded out by means of experimentation in the centrifugal pumps. Thus by diagnosing centrifugal pump using vibration data reduces cost and time for periodical maintenance. Shape memory alloy based ATDVA is used to control the amplitude of vibration due to hydraulic pulsation. Around 60% reduction in amplitude of vibration is evident for the varying excitation frequency between 336 Hz and 340 Hz due to hydraulic pulsation.

Road infrastructure in good condition is a key requirement for efficient transportation systems which leads to economic prosperity and improved quality of life. However, road surface conditions deteriorate over time according to traffic loads and environmental factors. Poor road conditions lead to congestion, accidents, lost productivity, and driver fatigue. This work considers the relationship between road pavement condition and vehicle speed, vibration, and in-vehicle noise. A 7 km section of the Grand Trunk Road, Peshawar, Pakistan divided into 280 segments (140 for each lane), of length 50 m was observed and the Pavement Condition Index (PCI) of each segment was determined based on the recurrent distress type and density according to ASTM D6433-011 guidelines. The number of very good, satisfactory, fair, poor, and very poor conditions are 51, 52, 81, 48, and 42, respectively. The mobile app BotlnckDectr was employed to measure vehicle speed, RPM, noise, vibration, GPS location, and time. Statistical analysis was employed to determine the relationship between PCI and vehicle speed, vibration, and in-vehicle noise. The results obtained indicate that noise and vibration increase by 3.3% and more than 30%, respectively, as the pavement condition changes from good to very poor, and vehicle speed decreases by 8.8%.

Vibration of bus driver's seat subjected under harmonic excitation, 3DOF (3 degrees of freedom) dynamic model is employed to carry out the calculation by 3 simulation methods. Mathematical model - numerical using Matlab programming language (Numerical model), Multi Body Dynamics (MBD) using Matlab Simmechanics tool (MBD model) and finite element model using Ansys APDL (FEM model) are employed. The strengths and limitations of each method are analyzed through the process of building models and retrieving the resulting data. The evaluation indexes include the response of driver's seat acceleration, response of the seat suspension's relative displacement and the seat suspension's vibration isolation ability according to two investigated cases of natural frequency and damping ratio. The obtained results from all 3 methods have no difference and the evaluation indexes are suitable according to the studies on vehicle vibration response. The Numerical model method requires the user to perform complex mathematical modeling. The MBD model method using Matlab Simmechanics is simpler, using built-in function blocks, requiring declarations to establish the exact initial equilibrium position of the mass elements. The FEM model method using Ansys APDL with keypoints and lines describing the model elements requires precise setting of the displacement of each keypoint. However, both the MBD and FEM model methods are only effective when investigating the response in the time domain for a particular instance of the excitation frequency. When analyzing the response in the frequency domain, which requires accessing and synthesizing data of many cases in the investigated frequency range, these two methods have many limitations in the calculation process, specifically, in performing complex computations with many loops and variables. Solving problems also takes longer than numerical method using mathematical model. The obtained results are analyzed in the time domain, frequency domain, and the value domain of the driver's seat suspension parameters. This result serves as a basis for developing the design of the driver's seat suspension system with nonlinear spring and shock absorber, and the selection of a calculation method suitable for each problem in the field of vehicle vibration.

Measurements on the Vehicle-Track Interaction and the Excitation of Railway-Induced Ground Vibration

Underground obstacle detection is the premise of unmanned driving. Aiming at the problem of obstacle detection in coal mines using a millimeter-wave radar, this paper proposes a filtering algorithm for invalid targets in roadways. Firstly, the target information output by millimeter-wave radar is analyzed, and the obstacle information of the underground roadway is extracted. Then, the filter algorithm is used to filter the resolved empty targets, false targets and non-potentially dangerous targets. The empty target whose target distance is zero in radar data is filtered directly. The pseudo targets generated by the radar performance or the instability of the echo signal are filtered through the radar-effective target life cycle method. The non-threatening targets beyond the horizontal range threshold and longitudinal range threshold are filtered directly. The experimental results show that the average filtering rate of the algorithm is more than 87.82% in the static state. When the speed is 5 km/h, the average filter rate is 87.70% for smooth driving and 86.83% for uneven road surfaces. When the speed is 7 km/h, the smooth driving rate is 87.54%, and the uneven road surface is 86.56%. When the speed is 10 km/h, the smooth driving rate is 86.50%, and the uneven road surface is 86.44%. Although the filter rate decreases with the increase of speed or vehicle vibration in the running state, the average filter rate of the proposed algorithm can reach more than 86% under all conditions.

With the development of underground rail, the problem that vehicle vibration affects the vehicle’s life-span and harms the health of the passenger has been concerned. In this paper, a vibration test system has been formed with data collecting instrument and acceleration sensors to collect the signals of the metro vehicle floor when it running at the ATO (Auto Train Operation) mode in the tunnel, Analyzing the regulation of vehicle vibration signal change that come with the change of the route condition, such as curve, slope, and so on. Obtain the relationship between the road condition and vehicle vibration. The analysis result shows that, the vehicle vibration not only be affected by the structure of the vehicle itself and the geological condition on which the track laid, but also has close relationship with the route condition.

This paper describes a study of vehicle localization using its vibration due to road surface roughness. The authors suggest a vehicle localization scheme in which a vehicle can identify its location on the road. The vehicle localization can be carried out matching the current vehicle vibration with the prior observed vehicle vibration in the database as a vibration map. In this paper, the longitudinal vehicle localization is carried out by observing the vehicle vibration with a smart phone on the dashboard. First, the authors examine the effect of the matching duration of the current vehicle vibration data to the prior observed vibration for the precise of vehicle localization. It is shown that the long duration matching is effective in more precise vehicle localization. Next, the authors evaluate the performance of the vehicle localization scheme using current vehicle vibration data and prior vibration data in the database observed from the same vehicle, and using the ones from a vehicle and the ones from another vehicle. It is shown that the vehicle localization error is about 2.5 meter when using vibration data from the same vehicle, and about 3.5 meter when using vibration data from a vehicle and another vehicle.

At the present time, due to the high density of the population and the increase in traffic problems, the extend of the time spent on the road often forces people to prefer public transportation. It is most important to ensure the safety of the passenger in the vehicle. In order to achieve this, it is necessary to ensure the health, safety and comfort of the vehicle driver as a priority. Especially in long distance transportation, it is important to increase the time spent on the road, the correct driving position of the driver and the movements suitable for ergonomics are important in terms of not losing the workforce. Health and risk are always associated with occupational diseases. Vehicle drivers are at high risk for discomfort from long term sitting positions and vehicle vibration. In this study, a design that will improve ease of use, ergonomics and comfort for bus and truck drivers has been developed within the scope of ISO 16121-1:2012 directive for M3/N3 class vehicles. Dynamic and static load vibration analysis simulation (FAE) was applied with the ANSYS program on the CAD drawings of the developed driver's seat. Revisions were made according to the inconsistencies encountered in the vibration analysis simulations performed under dynamic load and the analysis was repeated. Prototype production was carried out to ensure the accuracy of the design. The works for the vibration tests, which will correspond to the bad road test equivalent to 1,000,000 kilometers over the prototype, are continuing. All other validation tests were applied to the prototype produced driver's seat and positive results were obtained.

The vibration in vehicles has been measured in three translational axes and three rotational axes at the passenger/seat interface and on the floor beneath the seat. The level, frequency and direction of vehicle vibration was shown to depend upon vehicle type, vehicle speed and road condition. Vibration associated with vehicle suspension, engine and seat characteristics can be identified. Comparison of vehicle vibration levels obtained within each axis with discomfort levels obtained in the laboratory implied that, in the vehicles investigated, vibration in the translational axes produced greater discomfort than vibration in the rotational axes. Vertical vibration appeared to produce greater discomfort than fore-and-aft, lateral, roll, pitch or yaw vibration.

Inefficient packaging constitutes a global problem that costs hundreds of billions of dollars, not to mention the additional environmental impacts. An insufficient level of packaging increases the occurrence of product damage, while an excessive level increases the packages' weight and volume, thereby increasing distribution cost. This problem is well known, and for many years, engineers have tried to optimize packaging to protect products from transport hazards for minimum cost. Road vehicle shocks and vibrations, which is one of the primary causes of damage, need to be accurately simulated to achieve optimized product protection. Over the past 50 years, road vehicle vibration physical simulation has progressed significantly from simple mechanical machines to sophisticated computer-driven shaking tables. There now exists a broad variety of different methods used for transport simulation. Each of them addresses different particularities of the road vehicle vibration. Because of the nature of the road and vehicles, different sources and processes are present in the vibration affecting freight. Those processes can be simplified as the vibration generated by the general road surface unevenness, road surface aberrations (cracks, bumps, potholes, etc.) and the vehicle drivetrain system (wheels, drivetrain, engine, etc.). A review of the transport vibration simulation methods is required to identify and critically evaluate the recent developments. This review begins with an overview of the standardized methods followed by the more advanced developments that focus on the different random processes of vehicle vibration by simulating non-Gaussian, non-stationary, transient and harmonic signals. As no ideal method exists yet, the review presented in this paper is a guide for further research and development on the topic. Copyright © 2015 John Wiley & Sons, Ltd.

Vibrational problems in the domestic Small Horizontal Axis Wind Turbines (SHAWT) are due to flap wise vibrations caused by varying wind velocities acting perpendicular to its blade surface. It has been reported that monitoring the structural health of the turbine blades requires special attention as they are key elements of a wind power generation, and account for 15-20% of the total turbine cost. If this vibration problem is taken care, the SHAWT can be made as commercial success. In this work, Shape Memory Alloy (SMA) wires made of Nitinol (Ni-Ti) alloys are embedded into the Glass Fibre Reinforced Polymer (GFRP) wind turbine blade in order to reduce the flapwise vibrations. Experimental study of Nitinol (Ni-Ti) wire characteristics has been done and relationship between different parameters like current, displacement, time and temperature has been established. When the wind turbine blades are subjected to varying wind velocity, flapwise vibration occurs which has to be controlled continuously, otherwise the blade will be damaged due to the resonance. Therefore, in order to control these flapwise vibrations actively, a non-linear current controller unit was developed and fabricated, which provides actuation force required for active vibration control in smart blade. Experimental analysis was performed on conventional GFRP and smart blade, depicted a 20% increase in natural frequency and 20% reduction in amplitude of vibration. With addition of active vibration control unit, the smart blade showed 61% reduction in amplitude of vibration.

<div class="htmlview paragraph">Driveline torsional vibration in vehicles equipped with an automatic gearbox can lead to increased fuel consumption. At low rpm the torque converter of the automatic gearbox is active. The earlier the torque converter can be disengaged and bypassed by a lock-up clutch, the better the efficiency of the engine. Torsional vibrations in the drivetrain could prevent this early locking of the torque convertor and thus lead to a higher fuel consumption. Furthermore, these torsional vibrations can also lead to lower driver comfort.</div> <div class="htmlview paragraph">In order to improve the efficiency and the passenger comfort, a hybrid approach has been developed to predict the torsional vibrations of a full vehicle during a run-up manoeuvre on a chassis dyno, including transient effects. The hybrid approach is based on multi body modeling of the full car in LMS DADS, taking into account the flexibility of all major components of the powertrain.</div> <div class="htmlview paragraph">This paper describes the specific application of this hybrid approach for the creation and use of a predictive model of a complete rear driven car with a 6 cylinder-4 stroke powertrain and automatic gearbox. The model is built in a step-by-step pragmatic approach based on multi body modelling and validated using experimental databases of critical components.</div> <div class="htmlview paragraph">Using this model, several real live vehicle conditions are studied in a virtual way:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">full run up simulation with transmission in 3rd and 4th gear while the torque converter is in lock-up condition</div> </li> <li class="list-item"><div class="htmlview paragraph">Idle condition with the transmission in drive and braking applied.</div> </li> </ul> </div> <div class="htmlview paragraph">Other vehicle conditions can be simulated as well, the inputs that are required are the combustion forces corresponding to the manoeuvre, vehicle speed and the state of the gearbox. The model is built in a flexible way so that it can be extended to include more complex manoeuvres like gear shifting.</div> <div class="htmlview paragraph">This kind of simulations enables one to:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1</span> <div class="htmlview paragraph">identify operational excitation for specific engine orders;</div> </li> <li class="list-item"> <span class="li-label">2</span> <div class="htmlview paragraph">predict engine bracket vibrations resulting from the operational excitation and prescribed dynamic boundary conditions;</div> </li> <li class="list-item"> <span class="li-label">3</span> <div class="htmlview paragraph">predict driveshaft and propshaft torsional vibration, resulting from the operational excitation and prescribed loading;</div> </li> <li class="list-item"> <span class="li-label">4</span> <div class="htmlview paragraph">predict operational deflection shapes of the car assembly under operational conditions</div> </li> </ol> </div> <div class="htmlview paragraph">In a further stage, the virtual model is used to evaluate the influence of several design changes and to look for solutions that improve the efficiency and the NVH performance of the car. The adopted methodology is applicable for vehicle development purposes and has several advantages.</div>

Vibration in cars is undesirable because it causes discomfort to passengers, and can also lead to fatigue and failure of some parts of the vehicle. Therefore, the study and analysis of comments movements cart embedded in ever to research vehicles since the invention. And associated vibration cart passenger comfort, safety and stability of the vehicle. The researchers analyzed several vibration of vehicles by looking at different models, such as quarter wagon model ,and Half Car Model and full vehicle model with different types of excitement experienced by the vehicle and intended here excitement is a set of external forces arising from the terrain. This research includes a half vehicle linear model , written for four degrees of freedom plus one (4 +1 DOF) after addition degree of freedom which is driver / passenger seat system becomes a five degrees of freedom, also the vehicle body is assumed as a rigid body and taking into account the Bounce and Pitch. The system governing equations of motion are formulated by using the finite element method (FEM). A Fortran language computer program has been established for this purpose and used in the process covering (Simulation) and stand on the performance evaluation and analysis riding cart at the design stage and stand on the impact driver way through a study on the subject and the quality of the driver's seat, Two criterion of standards of comfort has been used, such as standard rate of absorbed energy (Average Absorbed Power) to be the norm over the driver comfort or not. And the comfort factor which is the vertical acceleration root mean square is used as an indication for the ride comfort. In factthe driver is the most important link in the process of using vehicles because the decision-maker and dominant direct the movement of vehicle.

Detecting and characterising shocks is challenging because they do not occur in isolation but are instead superimposed onto underlying vehicle vibrations which themselves are a result of the interaction with uneven road surfaces. Consequently, shocks are buried within vehicle vibration response measurements (usually acceleration). This paper presents the development and validation of an automated algorithm to detect shocks from vertical acceleration signals measured from road vehicles. To avoid inherent difficulties with experimentation, this initial paper is confined to numerical simulation whereby the response of two typical quarter-car truck models (one with air ride and the other with steel suspension) when travelling on artificially-generated random road elevation profiles laced with Hanning-shaped surface aberrations of known amplitude, lengths and location along the elevation profile. The shock detection algorithm was developed as a dual mode classifier to accommodate the two natural frequencies of each 2DoF quarter car models. Detection was implemented by first passing the vibration response signal through a band-pass filter around the two resonant modes in turn then calculating the filtered signals’ instantaneous frequency (envelope) by means of the Hilbert transform. Shock detection was based on the local peak-to-mean ratio (LPTMR) of the instantaneous magnitude where ‘local’ was defined by the duration of the filtered signal's impulse response function. Sensitivity analysis and validation were undertaken on artificially-generated roads of varying roughness onto which aberrations of known shape were superimposed. The effectiveness and limitations (detection threshold) of the algorithm were evaluated by creating a range of aberrations with a broad range of lengths (effective frequencies) and diminishing amplitudes. Results show that shocks of ‘significant’ magnitudes are always detected with no detection of false positives. As the road roughness increases relative to the aberration amplitudes, the resulting shocks become increasingly drowned-out by the vibration response due to the underlying road roughness, especially for the quarter-car model with steel suspension. The main conclusion is that the signal analysis approach taken is ultimately effective and needs to be further validated using experimental response data.

Predicting whole-body vibration (WBV) exposure of Malaysian Army three-tonne truck drivers using Integrated Kurtosis-Based Algorithm for Z-Notch Filter Technique 3D (I-kaz 3D)