International Journal of Vehicle Noise and Vibration (13 papers in press)
Three cylinder TGDI+CVT equipped driveline torsional vibration mode study over driveline component inertia/torsional stiffness
by Qian Zhao
Abstract: It is already known how MT equipped driveline torsional modes are distributed and influenced, and that is successfully applied to MT equipped vehicle NVH problem solving. However, it is still marginal for systematic CVT equipped driveline torsional modes sensitivity analysis, hence it is meaningful to establish the CVT driveline torsional vibration mode distribution and sensitivity to driveline component inertia/torsional stiffness. Thus the right driveline component parameters could be predefined from the very start of driveline development or tuned during the refining stage. The aim of this paper is to find out CVT equipped driveline torsional vibration mode sensitivity to driveline component inertia/torsional stiffness and establish rules to tune the driveline torsional vibration modes to mitigate torsional vibration-induced NVH issues.
Keywords: driveline; torsional vibration; CVT; inertia; torsional stiffness; sensitivity study.
Vibration suppression of a car engine frame via tuned vibration Absorber Design
by Jun Wei Sam, Hock Khuen Cheow, Jee-Hou Ho, Hoon Kiat Ng, Ai Bao Chai
Abstract: Whole body vibration degrades passengers ride comfort, which significantly affects their perception towards overall vehicle quality and induces health concerning issues under long term exposure. Motivated by the qualitative perception of whole body vibration experienced by users during vehicle ride, this paper focuses on the vibration characterisation of a car engine frame and proposes a design and implementation of a tuned vibration absorber (TVA) as the vibration attenuation solution in addressing the vertical vibrations, which are most perceived at the idling condition. TVA with frequency intentionally detuned to avoid exciting the second structural resonance throughout the nominal engine idle operating frequency results in a vibration acceleration amplitude reduction of 30.3% at the second order. The result shows that TVA is effective in attenuating tonal vibration at a particular troublesome frequency, such as the second order tonal vibration commonly experienced by conventional inline 4-cylinder engines.
Keywords: vibration analysis; vibration attenuation; tuned vibration absorber.
Time and magnitude dependent masking effects of vehicle's 2 Hz shock-type vibrations on the perception of vehicle's 4.5 Hz longitudinal shock-type vibrations for seated human subjects
by Nils Bulthaupt, Frank Gauterin
Abstract: In the literature there are no known studies regarding temporal masking effects of vehicle's shock-type vibrations. Since shock-type vibrations of different directions of movements, magnitudes and frequencies are acting on the human body while driving a vehicle, temporal masking effects may be relevant when evaluating vehicle's ride comfort. This study investigates temporal post-masking effects of vehicle's 2 Hz shock-type vibrations (masker) on the perception of 4.5 Hz longitudinal shock-type vibrations (test signal) for the seated human body. It was found that post-masking exists for the investigated vibrations. The masking effect is highly dependent on the time gap between masker and test signal: with increasing time gap the masking effect decreases. Furthermore the amount of masking increases with increasing masker magnitude. Both findings are consistent to the findings in psychoacoustics. In addition to that, the masking effect depends on the masker's direction of movement.
Keywords: vehicle's shock-type vibrations; ride comfort; human vibration perception; whole-body vibration; temporal masking effects; forward masking; post-masking; seated human body.
Application of optimised neural networks models in gears and bearings faults diagnosis
by Kaaïs Khoualdia, Elia Hadjadj Aoul, Tarek Khoualdia
Abstract: Gears and bearings are one of the most important machine components in the industrial world and detection of their faults has become a major trend. In the present article, in order to bring a reliable methodology for monitoring and diagnosis of rotating machinery failures, a test rig is implemented. However, to diagnose combined faults of gears and bearings, a monitoring system based on neural network model (NNM), is proposed. To train and test the NNM, the principal high frequency indicators, determined with the collected time domain vibration data, and codes of defects are used respectively as input and output data. A comparison of two learning algorithms, optimised by the Taguchi method, was done to determine the best NNM. Therefore, the proposed method is effective to study other various industrial cases.
Keywords: gear and bearing combined defects; fault vibration analysis; design of experiment; ANN; Taguchi method.
Effects of dampers on piston slapping motion
by Faisal O. Mahroogi, S. Narayan
Abstract: The secondary motion of piston skirt is a key contributor to Noise, Vibration and Harshness (NVH) emissions from an internal combustion engine. Previous works have focused on various mathematical models of this motion. In the present work, an overview of piston secondary motion is discussed. The scope of using a novel indirect method to control this motion is presented that involves use of vibration dampers. With use of suitable dampers a reduction up to the order of 50% was visualised. The discussed methodology can be used to design an optimised profile of skirt in order to control noise and vibrations emitted and hence satisfy customer benchmarks.
Keywords: vehicle noise; vehicle vibration; piston secondary motion; energy absorption.
Identify challenges in vibration measurements for rotating tyres using a finite element model
by Aakash Mange, Mohammad Behroozi, Javad Baqersad
Abstract: It is critical to identify the vibration characteristics of tyres when a vehicle travels on rough surfaces because the excitation from the road is transmitted to the axle through tyres. These vibrations can ultimately transfer into the cabin at an occupants interface points (seat, floor, steering wheel) and make the ride unpleasant for them. Experimental modal analysis using contact-based sensors such as accelerometers is usually used to obtain the modal parameters of non-rotating tyres. However, the mode shapes of tyres can significantly change when rotating. The non-contact techniques such as digital image correlation (DIC) has enabled engineers to capture 3D response of tyres during rotation. The acquired response can include deformations of the tyre at its resonant modes and the response of the tyre due to the excitations at harmonics of the rotation frequency. This makes it challenging to identify modes of the tyre. In the current paper, the measurements from a tyre testing on a dynamometer are replicated using a finite element analysis to identify the feasibility of obtaining mode shapes using data from a rotating tyre. Performing vibration analysis using computer-aided engineering (CAE) reduces the human effort of executing the complex experimental setup and performing the tests. Furthermore, it provides test engineers with an understanding of the dynamic performance of tyres. In this work, an explicit finite element analysis was performed on the rolling tyre. Using the data from the simulation, an operational modal analysis was performed to extract the modal parameters of the tyre in rolling condition. The results are analysed with those obtained from the experimentation of the Kettering Formula SAE tyre.
Keywords: tyre; NVH; finite element analysis; DIC; modal analysis.
Noise insulation properties of carriage wallboard of high-speed trains
by Zhigao Dang, Zhaoyong Mao
Abstract: With the increase of running speeds, noise transmission through carriage wallboard into the cabin has become a noticeable issue to be solved in the further development. This paper presents an analysis of sound insulation properties of carriage wallboard of high-speed trains. Finite element method (FEM) combined with acoustic-solid interaction (ASI) is applied to investigate the sound transmission loss (STL) performance. The predicted STLs are checked against experimental results, achieving good agreement in the trend. Then, the effects of several key parameters on sound insulation capability of the double-wall panel with different configurations of truss-core are systematically studied, including the inclination angle, the thickness, the configurations and the equivalent stiffness of the truss-core. To give intensive understanding of the STL behaviour, the equivalent stiffness of sound bridge is studied, which could provide some guidance for engineers from the perspective of sound insulation performance.
Keywords: noise insulation; carriage wallboard; high-speed trains; finite element method; acoustic-solid interaction; sound transmission loss.
Study on electromagnetic vibration of in-wheel motor for electric vehicle
by Qiping Chen, Jiachao Xie, Qiang Xiao, Ning Wang, Liang Wang
Abstract: In order to solve the electromagnetic vibration problem of in-wheel motors for electric vehicles, a numerical analysis method is presented for the modal analysis of the in-wheel motor. The finite element models of the inner stator core, inner stator core with winding and outer rotor are established. The analysis results show that the higher the order of modal vibration shape, the higher the natural frequency. The critical speed of the outer rotor is analysed and studied, which shows that the outer rotor will not cause greater vibration to the in-wheel motor when it works. The harmonic response of in-wheel motor is analysed and the displacement-frequency curves of the inner stator and outer rotor are obtained. The analysis results show that the in-wheel motor is not in the frequency range of electromagnetic force wave. When the frequency is higher, the deformation displacement amplitude will reach the maximum.
Keywords: electric vehicle; in-wheel motor; electromagnetic vibration; modal analysis.
Modelling neutral gear rattle for a light commercial vehicle
by Mrunal Kshirsagar, Satyajit Patil, Ansar Mulla, Sudheer Takalkar
Abstract: Acoustic levels have a significant influence on the ride comfort of road vehicles. Research efforts are going on to address the noise, vibration, and harshness issues of automobiles. Among others, gear rattling noise is a significant problem faced by the car industry. Automotive powertrains are being focused to reduce and isolate the torsional vibrations that are being transmitted and responsible for gear rattling. This work addresses a problem faced by a light commercial vehicle manufacturer about the reduction of gear rattle while the engine is idling. The rattle index is aimed to be lowered by introducing a pre-damper clutch plate instead of the conventional clutch plate that uses torsional vibration springs. A MATLAB Simulink model is developed to estimate the effect of spring stiffness on the rattle index of the system. The output of the model is validated with the help of an experimental setup that consists of a data acquisition system and FFT analyser. The accuracy of the Simulink model is reported by comparing the results of simulation and experimental works. The rattle index was successfully decreased with the help of the pre-damped clutch plate, and the model is found to be accurate enough to estimate the rattle index for future proposed development work.
Keywords: neutral gear rattle; torsional vibrations; pre-damper spring; rattle index; spring stiffness.
Drum brake noise reduction
by Sushant Magdum, Samir Kumbhar, Karanam Venkata Mangaraju, Venkatesh Govindan
Abstract: Squeal noise generally occurs by the friction-induced self-excited vibration in the braking system, which greatly affects rider comfort as well as the surrounding noise level. The reduction in drum brake squeal noise has become a more challenging and trending problem in two-wheeler industries. In this paper, squeal noise is reduced by changing the stiffness of brake shoe and liners by means of liner modification with different width and depth of the liner slot. The effect of changes in liner geometry on drum brake squeal noise reduction is studied analytically and verified experimentally. A full nonlinear perturbed modal analysis is used to solve the complex eigenvalue problem, which helps to know the stability of the system. In order to validate the analytical results, experimental tests are performed at a certain slow speed having low brake pedal force. The experimental results show that the drum brake squeal noise is found to be reduced by a significant amount by applying the proposed method. It is found that significant modification in the geometry of the liner in view of noise reduction has little effect on vehicle performance.
Keywords: squeal noise; drum brake; full nonlinear perturbed modal analysis; stability.
Fatigue life study of suspension ball joints on the basis of ride quality
by Naveed Ahmed Khatri, Fadly Jashi Darsivan, Waleed F. Faris, Ahmad Faris Bin Ismail
Abstract: The MacPherson quarter car model was used to determine the fatigue life of a suspension ball joint using a non-conventional approach that combined rigid body dynamics with finite element (FE) analysis. In this research, a quarter car model was subjected to the ISO random road profile with a pothole and a speed bump in order to obtain the ride quality and the reaction forces occurring at the ball joint. After classifying three ride qualities, another simulation was conducted on this model to study the stress distributions, in which the ball joint and its socket were treated as flexible bodies. Finally, based on the results of the FE analysis, the fatigue life of the joint was measured for each ride quality. Based on the findings, it was concluded that a good ride quality has an adverse effect on the fatigue life of the ball joint component. ANSYS Workbench and CATIA V5 were used for modelling and simulation.
Keywords: quarter car; suspension ball joint; fatigue life; ride quality; reaction forces; FEA; ANSYS.
Magneto-rheological damper semi-active suspension system control using fuzzy logic controller compared with optimised passive suspension
by Waleed Faris, Nouby Ghazaly
Abstract: Various technologies are applied to vehicle suspension, because of the increasing demand for vehicle stability and passenger comfort. The magnetorheological damper has the ability to adjust the damping coefficient dynamically, and fuzzy logic controller development enables us to obtain the desired damping force. The combination of using magnetorheological damper and controlling it using fuzzy logic will improve the performance of the suspension system. A two degree of freedom quarter car semi-active Bouc wen Magneto Rheological damper model simulated in Simulink composed by a random road profile was used. The controlled magneto-rheological semi-active suspension system was compared by passive suspension system and optimised passive suspension system. The result shows that the magneto-rheological semi-active suspension system controlled using fuzzy logic controller gives better ride comfort and stability than the passive suspension and optimised system. The results show that the MR reduction in acceleration is about 90%, suspension working space about 81%, the tyre deflection 93% and the jerk about 95% compared with the passive suspension system. Also the MR reduction in acceleration is about 96%, suspension working space about 77%, the tyre deflection 90% and the jerk about 95% compared with the optimised passive suspension system. The results are showed in time domain, frequency domain and root mean square values.
Keywords: quarter car model; semi-active suspension system; MR damper; fuzzy logic controller.
Passenger body vibration analysis in active quarter car model using PID sliding surface based variable gain super twisting control
by Dev Dutt Singh
Abstract: This paper is related to passenger ride comfort improvement using an active quarter car system. The selected control strategies include PID-based Super Twisting Control (PID-STC) and PID-based Variable Gain Super Twisting Control (PID-VGSTC) for reducing the passenger body vibration response. ISO 8608 standard is used for random road profile generation while ISO 2631-1 standard guidelines are used for ride comfort comparison. The ride comfort performance of passenger body is evaluated and compared using simulation results taking acceleration and displacement response. The ride comfort improvement results shown by active suspension with PID-VGSTC controller were highest compared with other control strategies.
Keywords: quarter car model; passenger ride comfort; PID-VGSTC control; ISO 8608 standard; ISO 2631-1 standard.