Squeak Noise Research Articles

The occurrence of squeaking under wear testing standards for ceramic on ceramic total hip replacements

Ceramic on ceramic total hip replacement clinical reports may on occasion note a noise or squeaking. There is much debate on whether this is an actual concern, but some medical centres want to avoid any possible negative impact on the patients’ wellbeing due to the noise generated.The aim of this study was to determine what sound frequencies can be picked up from hip testing standards for ceramic on ceramic under different lubrication conditions. The ISO-14242-1 (35° cup angle) and ISO-14242-4 (55° cup angle with a 4 mm translational mismatch) standards were used for testing with dry, water and serum lubrication conditions up to 10000 cycles.No sound was detected for water and serum conditions under standard walking (ISO-14242-1) testing. An audible noise with a frequency range of 0.4–0.8 kHz was picked up within 600 cycles under water and edge loading (ISO-14242-4) conditions. All dry testing produced a high pitch squeak when the frequency was higher than 2 kHz. One sample under dry edge loading conditions had an audible noise of 0.8 kHz, considered not as squeaking, as it was not high pitch. Dry testing for both, standard walking (ISO-14242-1) and edge loading (ISO-14242-4) conditions, which resulted in a high pitch noise, had a frequency range of 2–8 kHz and 5–9 kHz respectively. One sample tested with edge loading and serum produced a faint squeak noise after 6000 cycles with a frequency of 7 kHz.Edge loading due to ISO-14242-4 conditions had an increased torque which may be playing a role in increased friction leading to noise. Edge loading conditions were more prone to the generation of audible noise and squeaking whilst under lubricated conditions.

Attempts and initiatives for mobility research including guideway transportation at the Mobility Experimental Field of the University of Tokyo

This paper describes several trials performed CHIBA test track 2 in the university of tokyo. These trials including a low-speed wheel climbing test using test trolley, expansion of facilities on CHIBA test track 2, coloring of track and bogie with water-based rust prevention and improved visibility, suppression of track temperature rise, Visualization of the contact position between wheel and rail, suppression of squeak noise, trials of non-contact speedometers, and data collection for detecting obstacles in the running space.

Experimental study on the factors affecting squeak noise occurrence in automotive suspension bushings

In this study, friction tests are performed, via a custom-built friction tester, on specimens of natural rubber used in automotive suspension bushings. By analyzing the problematic suspension bushings, the eleven candidate factors that influence squeak noise are selected: surface lubrication, hardness, vulcanization condition, surface texture, additive content, sample thickness, thermal aging, temperature, surface moisture, friction speed, and normal force. Through friction tests, the changes are investigated in frictional force and squeak noise occurrence according to various levels of the influencing factors. The degree of correlation between frictional force and squeak noise occurrence with the factors is determined through statistical tests, and the relationship between frictional force and squeak noise occurrence based on the test results is discussed. Squeak noise prediction models are constructed by considering the interactions among the influencing factors through both multiple logistic regression and neural network analysis. The accuracies of the two prediction models are evaluated by comparing predicted and measured results. The accuracies of the multiple logistic regression and neural network models in predicting the occurrence of squeak noise are 88.2% and 87.2%, respectively.

Innovative squeak noise prediction: An approach using the harmonic balance method and a variable normal contact force

A flawless interior acoustics is a customer requirement in automotive industry. Any disturbing noise e.g. squeak or rattle must be avoided to meet the customer’s expectations regarding quality. This work presents an improved approach to predict squeak noise. For this purpose, a test rig generating the underlying stick-slip phenomenon by harmonic excitation is used and a corresponding finite element model is built describing the system’s dynamic behavior. The Harmonic Balance Method is applied for solving the nonlinear equations of motion. The major difference to previous approaches consists in the implementation of a contact algorithm allowing variable normal forces in the contact domain. The calculated nonlinear system response is compared to existing methods using a constant normal force. The proposed method is capable of predicting odd harmonics, which is a significant improvement in assessing squeak noise. Furthermore, good agreement between simulation and experiment is observed which validates the approach.

Research on Squeak Noise from Polypropylene in Frictional Contact with Leather for Automotive Interior Assembly

To explore the mechanisms of squeak generation in automotive interiors, stick–slip experiments on polypropylene versus leather were conducted under various conditions. The friction properties were researched with changes in normal force, velocity, and temperature and static friction coefficients were generally lower at low temperature, higher at room temperature, and intermediate at high temperature and generally increased with an increase in velocity from 1 to 4 mm/s except in some individual cases. The dynamic friction coefficients as a whole presented a significant decrease but displayed similar trends in comparison with the static values. A simplified spring–mass model was built to illustrate the stick–slip physics of movement of polypropylene versus leather. The concomitant squeak characteristics are discussed. Risk priority indexes were acquired to evaluate the level of squeak noise. The inverse of the impulse rate obtained from stick–slip tests was perceived as the crucial threshold for squeak evaluation. A finite element simulation was developed to study the squeak problems of a trimmed vehicle door, and some risk locations were identified by comparing the maximal peak-to-peak amplitude of relative displacement in the main direction with the inverse of the tested impulse rate. The weak area where the squeak originated can be located from the modal contribution analysis for enhancement in the design phase.

Squeak Noise Prediction of a Door Trim Panel Using Harmonic Balance Method

<div class="section abstract"><div class="htmlview paragraph">Squeak and rattle noise in a vehicle’s interior is perceived as an annoying sound by customers. Since persistent noise (e.g. engine, wind or drive train noise) has been reduced continuously during the last decades, the elimination of sounds, which have their origin in the vehicle’s interior components, is getting more important. Therefore, noise prediction based on simulation models is useful, since design changes can be realized at lower costs in early virtual development phases. For this task, linear simulation methods are state of the art for the identification of noise risk, but in general without knowing if a sound is audible or not. First approaches have been developed based on the Harmonic Balance Method to predict squeak noise and assess their audibility. This paper presents vibroacoustic measurements at a door trim panel for squeaking and non-squeaking configurations. Vibrations are excited harmonically by a force controlled low noise shaker. The system response is measured in a semi-anechoic chamber by acceleration sensors and audibility is assessed. Additionally, a 3D finite element model is built and the Harmonic Balance Method using a dry friction law is applied to predict the acoustic behavior. Finally, the simulation results are compared to the measurements. A good agreement between simulation and experiment can be observed.</div></div>

Squeak and rattle noise classification using radial basis function neural networks

In this article, an artificial neural network is proposed to classify short audio sequences of squeak and rattle (S&R) noises. The aim of the classification is to see how accurately the trained classifier can recognize different types of S&R sounds. Having a high accuracy model that can recognize audible S&R noises could help to build an automatic tool able to identify unpleasant vehicle interior sounds in a matter of seconds from a short audio recording of the sounds. In this article, the training method of the classifier is proposed, and the results show that the trained model can identify various classes of S&R noises: simple (binary clas- sification) and complex ones (multi class classification).

Novel method for identifying and diagnosing electric vehicle shock absorber squeak noise based on a DNN

Abstract Suspension shock absorber squeak noise is becoming increasingly apparent within the overall noise level of all-electric vehicles (EVs) due to the extensive reduction in power system noise. Although the early identification of shock absorber squeak noise via bench tests can save costs and time, such identification remains a challenge for the industry. In this paper, a novel method for identifying and predicting EV shock absorber squeak noise is proposed. In contrast to other studies on shock absorber noise that focus on highly complex designs and feature extraction, this study uses the original time signals and frequency spectra to predict the shock absorber squeak noise based on deep neural networks (DNNs). To implement this method, an EV road test is conducted on five different pavements, and the grade evaluation method (GEM) is applied in a subjective evaluation of the annoyance of the shock absorber squeak noise. The vibration signals of the shock absorber piston rod are collected and preprocessed via a bench test. Then, a DNN is developed to automatically extract the shock absorber squeak noise feature and intelligently identify the subjective annoyance (SA) grade of the squeak noise. This novel identification method effectively solves the problem in which the annoyance level cannot be evaluated via the GEM by relying on the rich auditory experience of the evaluation subject. In the validation analysis, the DNN outperforms two other intelligent methods, the genetic algorithm-back propagation neural network (GA-BPNN) and the genetic algorithm-support vector machine (GA-SVM), based on a confusion matrix and an error analysis.

Optimal Design for the Rear-Glass Joint of an Automobile for Squeak and Rattle Noise Reduction

Ever since vehicle noise, vibration, and harshness (NVH) reduction technology made dramatic improvements, vehicle interior noises represented by Squeak and Rattle (S/R) becomes an ever more important factor to improve the emotional quality of vehicles. Generally, people detect S/R noises on automotive interior parts, brake system, suspension, Body in White (BIW), etc. Among them, the rear-glass joint is a major source for vehicle interior noise, and can cause S/R noises under a variety of environmental and driving conditions. This study uses, two approaches, experimental and numerical approaches, to define the cause of S/R noise at the rear-glass section. Based on these two approaches, this study confirms that S/R noises generate through the contact between bottom side of molding and BIW. The sealant penetration length, panelmolding distance, and sealant width are the parameters affecting noise generation. In addition, this study created an optimal design with Design of Experiments (DOE) of the rear-glass joint. The design maximized the sealant penetration length, which is a parameter that majorly affects noise. The optimal design comprises of two steps: sealant injections shape optimization and rear-glass joint parameter optimization. Each step is carried out with FEA and validated by sealant penetration experiments. Through these optimizations, this study obtained an optimum combination of design parameters and fignificantly reduced the noise generated by rear-glass section.

Squeak Noise Prediction for Systems with Dry Friction Damping

<div class="section abstract"><div class="htmlview paragraph">Squeak noise is a phenomenon which is often categorized as BSR, i.e. buzz, squeak and rattle. It arises from stick-slip movement between parts in contact. In a vehicle cabin, this noise is undesirable and has to be prevented. Simulation methods are used to find critical contact conditions in the construction at an early stage of development. For accurate predictions, these methods have to take nonlinear behavior into account. In this paper, the Harmonic Balance Method is applied to a three-dimensional finite element model in order to calculate vibrations of systems with dry friction contacts. The system’s sensitivity to different contact formulations is investigated. For a reference, a test rig has been built. It consists of a beam with harmonic excitation. The beam is clamped at one end. At the other end it is in dry friction contact with a plate. Different excitation levels, frequencies, normal contact forces and material pairs are evaluated. The system’s response in time and frequency domain is compared to corresponding simulation results. The contact definition is updated to achieve accuracy in calculated dynamic responses. Results of calculation can be used to estimate the radiated noise, e.g. by determining the Equivalent Radiated Power.</div></div>

Design Parameter Study of a New Test Apparatus Developed for Quantitative Rating of Squeak Propensity of Materials

A novel, unique squeak test apparatus was developed to measure squeak propensity of a given pair of materials with a purpose to build a database for automotive engineers. The apparatus employs a sprag-slip mechanism to generate friction-induced, unstable sliding motion between the two materials that leads to a repeatable squeak noise to enable quantitative rating of the squeak propensity of a given pair of materials. An analytical model of the system was developed to study dynamic characteristics of the mechanism to gain insights to design the test apparatus. Stability analysis of the system identified unstable regions of the motion in parameter planes defined by the kinetic coefficient of friction and the attack angle. Furthermore, the effect of these system parameters on the amplitude of the limit cycle was investigated to obtain guidance to design the device. An automatic rating algorithm of squeak noises previously developed by authors was employed to calculate the squeak propensity of the material pairs. A practical engineering procedure is envisioned that can handle squeak problems in the design stage more effectively by taking advantage of such a squeak propensity database.

Finite element algorithm reproducing hip squeak measured in experiment

In this study, the frequency spectrum of squeak noise in hip joint system is measured in experiment. The numerical reproduction of hip squeak signal involves the formulation of the finite element geometry, the analytical contact kinematics such as Hertz theory and Coulomb's law and the mode-discretization. For general approach, the contact kinematics are analytically modeled to easily adjust the contact location, the contact area, the rotation direction, the pressure distribution, the friction law, and so on. Furthermore the friction stress vectors act on the 3-dimensional spherical contact surfaces where they can be divided into the steady-sliding and its transverse slip directions.Numerical calculations for the various contact parameters are conducted to investigate the possibility of hip squeak occurrence and the nonlinear oscillations after the onset of squeak are also solved. In the transient analysis, the periodic limit cycle of hip squeaking is shown to be the stick-slip type oscillation. Then the numerical frequency spectrum is qualitatively compared with hip squeak signal measured in experiment. The stick-slip oscillation during hip squeaking and its contact behavior will be also discussed over the contact area within one period.

Finite element analysis for friction noise of simplified hip joint and its experimental validation

In a hip joint system, squeak noise often occurs due to friction between the ball and hemispherical cup. To analyze the dynamic instability induced by friction in the hip joint system, the dynamic ball joint model was constructed by using the finite element method. The results from stability analysis revealed that the mode-coupling type instability occurred for one bending mode and its adjacent composite mode with the axial and transverse displacements with the increase of friction coefficient. The vitro squeak test and vibration modal tests confirmed that squeak arose near the frequency of the mode pair.

Squeak and rattle noise prediction for trimmed door of a car using hybrid statistical energy—Finite element method analysis

Squeak and rattle (S&R) noise are important in-cabin sources of annoyance for occupants. Originally, S&R is generated as a result of colliding and slamming of car’s trim and body structure, which in turn occurs because of the dynamic displacements of components excited by road and powertrain. Squeak noise is interpreted as periodic stick and slip phenomena in the contact boundary of two neighbor surfaces. While rattle noise is the emitted noise when adjacent surfaces collide and impact. Both squeak and rattle phenomena happen in high-frequency range, even though the excitation sources (road and powertrain line) works in low frequency range. In practice, squeak and rattle noise can be minimized via controlling the gaps through a tolerance analysis, as well as the appropriate choice of materials. In this research, potential S&R sources are investigated for the trimmed door of a car using clearance analysis. Impact statistics and overall force level at potential rattle places are calculated through random vibration excitation analyses and afterwards, acoustic sensitivity, overall acoustic response, and loudness are calculated by the aim of hybrid SEA-FE method. The results of this prediction will be used in noise and vibration control plan of the whole car in design phase.

Pin-on-disk를 이용한 기초 마찰소음 실험 연구

Squeak noise is studied by using the pin-on-disk system with aluminum pin and steel disk. Noise induced by friction is measured with respect to the normal loads and sliding speeds. The negative slope of friction-velocity curve is seen when the squeak noise occurs. It is found that the normal load influences on the sound level of squeak noise. From the hammering test, the major frequency of the squeak noise is shown to correspond to one of system modes, which implies that squeak phenomenon arises from the unstable system modes. The result of FE analysis shows that the major squeak mode is the bending mode of the pin.

Dolphins (Tursiops truncatus) use multiple auditory mechanisms for detecting tonal signals in natural and anthropogenic noise

The dolphin's ability to detect a 10 kHz tone masked by a variety of noise types was measured using a standard band-widening paradigm. Maskers included natural noise (rain, snapping shrimp, and ice squeaks), anthropogenic noise (pile saw and boat propeller cavitation) and statistical noise (Gaussian and comodulated noise). For most noise types, detection thresholds increased as noise bandwidth increased up to 1 kHz (the dolphin's critical bandwidth at 10 kHz). Masking patterns for narrow-band maskers were similar regardless of the masker type. However, for noise bandwidths greater than 1 kHz, masking patterns diverged by as much as 23 dB depending on the noise type. The power spectrum model provided reasonable predictions for Gaussian, rain, pile saw, and boat noise masking patterns. Additional experiments suggested that mechanisms related to temporal envelope processing (across-channel envelope comparison and within-valley listening) determined masking patterns for snapping shrimp and comodulated noise. Thresholds in ice squeak noise, which proved to be the most effective masker, were related to the dolphin's inability to discriminate the signal from the background noise rather than inability to detect the signal. These results suggest that the dolphin auditory system uses multiple mechanisms for signal detection in complex noise [Work supported by the ONR.]

자동차 시트 틸팅 각도에 따른 기어박스 마찰소음 영향도

The squeak propensity in the gear box of an automotive seat system is investigated analytically. The mating parts in the gear box are the lead screw and the nut, where the friction stresses are exerted on the thread of the screw. The lead screw is modeled as a circular beam allowing the bending and torsional vibrations. In the system, the lead screw converts rotating to translating motion so that it moves the automotive seat slightly tilted on the floor. The tilting angle is considered one major parameter in this study. Therefore, the equations of motion associated with the non-conservative friction force are derived with the inclusion of the tilting angle. It is found that the squeak noise corresponds to the several bending modes of the lead screw and its propensity is increased by the tilting angle of the seat.

Squeak noise in lead screw systems: Self-excited vibration of continuous model

The dynamic instability of a spinning lead screw in contact with a screw nut is investigated analytically. The lead screw is modeled as a circular beam vibrating in transverse and torsion direction. The contact kinematics between the lead screw and the nut is described on the contact threads in the lead screw. The onset of squeak noise is numerically predicted with a variety of system parameters. Stability analysis shows that the transverse vibration modes can generate squeak noise in the lead screw system. It is highlighted that squeak noise can be controlled by system design parameters in such a manner that the squeak propensity is dependent on rotation speed, screw radius, axial load, contact location, and so on.

2405 車輪/レール間摩擦制御時の曲線通過シミュレーション(OS9 接触問題とトライボロジ,OS9 接触問題とトライボロジ,TRANSLOG 2006)

In the subway lines of Tokyo Metro, there are so many tight curves that may cause squeak noise, excessive wheel/rail wear and also rail corrugation. To solve these serious problems, onboard friction control system with friction modifier has been developed by authors and has been equipped on commercial trains as a trial. With the system, the balance between supply and consumption of friction modifier is very important for the system design. That is to say, in order to obtain the enough effect of friction control steadily, it is natural that appropriate quantity of friction modifier should be required. In this paper, results of numerical analysis with multi-body dynamics (MBD) software, A'GEM, and analysis with the result of test run with commercial train are reported. And with the results authors show the possibility to realize the feedback control of spraying friction modifier with the detection of the load acts on mono-link of the bogie truck.

A Method to Realize The Friction Control between Wheel and Rail in Service Lile (Development of On Board Friction Control System)

The purpose of this study is to demonstrate how the friction control between wheel and rail can solve wheel/rail contact problems, such as wheel slip, rail corrugation, squeak noises, wheel/rail wear and so on. This paper presents the results of the fundamental tests which were carried out to clarify the physical performances of friction modifier, and general outline of “On Board Friction Control System” developed by authors. The performance of the proposed system is proved in experiments on the service line, showing the decrease of harmful wheel/rail forces, reduction of squeak noise, and prevention of rail vibration in lateral direction.