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Due to a large number of degrees of freedom and connected powertrain functionalities, the development of operating strategies for plug-in hybrid electric vehicles is an especially complex task. Besides optimizations of drivability, noise, vibrations and harshness as well as energy efficiency, the main challenge lies in ensuring emissions conformity. For this purpose, test vehicles are typically applied to achieve a realistic test and validation environment. However, operating strategy calibration using test vehicles has the drawbacks, that (i) it is very time consuming and cost intensive, (ii) it can only be conducted in late development phases and (iii) cannot be applied to reproducing driving loads for a valid comparison. To overcome these issues, this paper presents a consistent engine-in-the-loop approach combining real engine hardware and multiple software elements to represent PHEV behavior at the engine test bench. Thereby, an environment is created, which allows for realistic, flexible, cost efficient and reproducible testing. The effectiveness of the presented framework is evaluated by comparing relevant on-road measurements with their reproduction at the engine test bench. The results show that the vehicle on-road behavior can be replicated using the described testing environment. Particularly engine start/stop behavior and load levels—the core functionalities for operating strategy calibration—are matched. The proven level of realism in powertrain behavior enables further use cases beyond on-road measurement reproduction, i.e. varying individual component properties and observing real-world consequences at the test bench without the need for vehicle tests.

Noise, vibration, and harshness (NVH) issue in switched reluctance machines (SRMs), originating from their doubly salient structure and unique principle of operation, is addressed in this work by proposing a structural design modification in the stator, which increases stiffness to mass ratio of the structure. A 24-slot 16-pole (24s/16p) SRM designed with the aim of automotive application is studied here for the NVH optimization, at different target operating points, using stator pole bridges. Stator pole bridges link consecutive stator teeth to provide additional stiffness to the stator structure. Average torque reduction due to flux shorting in stator pole bridges is tackled by proposing a low-permeability material, with considerable stiffness, which has not yet seen its’ application in SRM NVH domain. Multiphysics aspects of stator pole bridge design encompassing electromagnetic radial force, mechanical stress, steady-state temperature distribution, and acoustic noise analyses are presented in this article. Possible manufacturing issues are considered during the design phase and appropriate measures are implemented to facilitate easier construction of two 100-kW prototypes. The final design with stator pole bridges and a baseline design without any stator pole bridges are prototyped, after rigorous multiphysics optimization, for extensive testing. Experimental results verify simulation outputs and report a maximum noise reduction of 12.52 dBA in the stator pole bridge model compared to the baseline SRM.

Acoustic and rhythmic temporal patterns may have important roles both in animal vocalizations and in human music. Male rock hyraxes, Procavia capensis, advertise their quality and emotional state by singing a long complex song, comprising repetitive elements. Research has revealed that the temporal structure of hyrax songs is similar to a musical crescendo, as it includes a gradual increase in amplitude, along with several additional acoustic and structural parameters, throughout the song. In hyrax songs, the snort is a relatively rare, low and harsh vocal element, which increases in number as the song progresses. We have previously shown that mean snort harshness is positively linked to both the singer's social status and testosterone levels, possibly reflecting inner arousal. Here, we measured the changes in snort harshness and length during natural hyrax songs. Our results indicate that in mature males, harshness, quantified by shimmer and jitter, increases as the song progresses. We suggest that increasing snort harshness may either (1) indicate the progression of inner excitement or aggression throughout the song or (2) that the harshness may reflect the difficulty of vocal control following increasing effort or the physical fatigue of the vocal cords. In western culture music, such progression is used to increase listener tension and thus retain attention, preventing possible habituation. Thus, understanding the development and progression of challenging elements within animal communication systems may reveal a key fundamental root of modern musical structure, and shed light on the evolutionary basis of musical perception.

Owing to the continuous development of the automobile industry, increasingly stringent performance requirements for noise, vibration, and harshness of automobiles are being presented. Interior noise control in high-speed vehicles has not been adequately addressed, owing to the complex mechanism of noise generation. As simulations performed previously focused on vehicle wind noise and tyre noise cannot adequately predict the effect on passenger ear-side noise, these issues are investigated in this study. Their effects on passengers are investigated using transfer path analysis. An anti-noise operational transfer path analysis is proposed to study noise generated in high-speed vehicles. The established anti-noise operational transfer path analysis model can eliminate crosstalks between noise source signals of different transmission paths. The model is validated by comparing the measured and calculated values of the anti-noise operational transfer path analysis model. The coherence of the input noise signal and the ear-side noise signal of the passenger is assessed using coherence analysis. By calculating and categorising the contributions of different noise sources in different locations and types, the main noise sources affecting passenger comfort are determined. The result indicates that the main noise sources affecting the passenger’s ear-side noise change from engine noise to left-A wind noise and tyre radiation noise with increasing vehicle speed, in which the proportion also increase. The proposed anti-noise operational transfer path analysis is suitable for the interior-noise analysis of high-speed vehicles, and this study may serve as a reference for future studies regarding active and passive noise control in high-speed vehicles.

Constant velocity (CV) joints are the primary component of a vehicle that transmits the driving force from an engine/transmission to a wheel at a constant speed. A CV joint comprises numerous mechanical parts. The roller and housing are in contact and, therefore, subjected to contact stresses. Contact stress causes sliding friction because of microslip in the contact area inside the CV joint. This internal friction generates an axial force, dependent on the kinematics. A generated axial force (GAF) is caused by the internal friction in a plunging-type CV joint. This force can have a direct impact on the degradation of the noise, vibration, and harshness characteristics of a vehicle. The typical vibration of a CV joint transmitted to the vehicle is shudder, which degrades the lateral oscillation of the vehicle. Shudder is generated by the GAF and results from the rotation of the CV joint during rapid acceleration, stimulating the lateral movement of the vehicle and causing discomfort to passengers. In this study, the radii of the roller and the housing were selected as the design parameters, and the contact stress was minimized through the sensitivity analysis. The GAF of the existing CV joint and optimized CV joint are compared through a multibody dynamic simulation. An axial force test is performed on the CV joint of a C-segment vehicle to verify the dynamic simulation results. The friction characteristics of the greases used in the CV joint were also confirmed by the schwingung reibung verschleiss (SRV) friction test. The results obtained can be used to reduce the GAF of the CV joint and to build an optimized CV joint model.

Determining the root causes of various noise, vibration and harshness phenomena in modern automotive drivetrains is a critical task for industry, since noise, vibration and harshness issues often result in worsened driving experience. The aim of the current research is to investigate the dynamics during dry clutch engagement and the associated – often problematic – oscillations. This paper reports the development and partial validation of numerical models to study dry clutch behaviour. The models are used to investigate the influence of clutch and throttle actuation on the occurrence of unwanted clutch oscillations. The dynamic coefficient of friction between the clutch interacting surfaces was measured using a pin-on-disc rig under different slip speeds and contact pressure conditions, which are representative of a typical clutch engagement manoeuvre. The paper highlights the occurrence of instability issues in clutch dynamics (disc radial mode) as potential generators of aggressive noise, vibration and harshness, particularly during two different clutch pedal actuations. Such analysis has not hitherto been reported in the open literature.

The content of noise, vibration, and harshness is an important part of the undergraduate mechanical engineering program education to prepare students ready for their future career, and it has received great attention from educators. Since course content in noise, vibration, and harshness usually requires more mathematical background knowledge and skills such as problem-solving in differential equations and linear algebra, students at the undergraduate level usually experience difficulty in the problem-solving work in noise, vibration, and harshness, though they have already completed the pre-requisite mathematics courses. In this paper, a new schedule and course content design for noise and vibration courses are introduced. By embedding active learning and design during projects, the students were able to obtain a better understanding of the concept of acoustics and vibration, as well as applying the knowledge from lectures to labs so they can connect the learning to real-world applications. Four projects are introduced and explained. To evaluate the effectiveness of the course, student outcomes are assessed and discussed.

Road noise is expected to become even more important in the vehicle product development cycle due to electrification and challenging lightweight/emission targets. In this study, a topology optimization algorithm is applied to determine the damping pad layout on the roof and floor panels of a Body-in-White (BIW), being the dominant contributors on road noise, vibration and harshness (NVH) performance of an automotive. Optimization algorithm yields the prescribed % of the surface area of these panels where the damping pad should be distributed set by the automotive Original Equipment Manufacturers (OEMs). The objective function is the minimization of the overall acceleration of these panels for the frequencies up to 200 Hz, while the weight of the BIW is considered as the optimization constraint. The results of the optimization are compared with the road NVH performance of panels with full damping and no damping. The optimization results indicate that by using 25% of the damping pad on the roof and floor panels improve the vibration performance especially in the frequency range of 80 Hz to 150 Hz significantly compared to bare BIW panels. Besides, the performance of the 25% damping is almost same as the application of full damping pad for frequencies between 90 Hz to 110 Hz. The results show that the methodology is able to address the trade-offs between road NVH and weight targets effectively.

Hypothesis This study tests the hypothesis that it is possible to find tone or noise vocoders that sound similar and result in similar speech perception scores to a cochlear implant (CI). This would validate the use of such vocoders as acoustic models of CIs. We further hypothesize that those valid acoustic models will require a personalized amount of frequency mismatch between input filters and output tones or noise bands. Background Noise or tone vocoders have been used as acoustic models of CIs in hundreds of publications but have never been convincingly validated. Methods Acoustic models were evaluated by single-sided deaf CI users who compared what they heard with the CI in one ear to what they heard with the acoustic model in the other ear. We evaluated frequency-matched models (both all-channel and 6-channel models, both tone and noise vocoders) as well as self-selected models that included an individualized level of frequency mismatch. Results Self-selected acoustic models resulted in similar levels of speech perception and similar perceptual quality as the CI. These models also matched the CI in terms of perceived intelligibility, harshness, and pleasantness. Conclusion Valid acoustic models of CIs exist, but they are different from the models most widely used in the literature. Individual amounts of frequency mismatch may be required to optimize the validity of the model. This may be related to the basalward frequency mismatch experienced by postlingually deaf patients after cochlear implantation.

In December 2019, the first reported case of COVID-19 was brought to notice in Wuhan, China. The virus has novel characteristics, its harshness is unpredictable, its transmission ability is extremely powerful, and its incubation period is comparatively larger. Thus the outbreak emerged as a pandemic worldwide. World health and socio-economy is getting continually affected by COVID-19 since its outbreak. It will be easier to handle the situation if an automated diagnostic system is developed, capable of separating COVID-19 affected images from bulk images obtained from a mass screening process. Kaggle’s online chest X-Ray image dataset has been considered for this work evaluation. Healthy and COVID-19 affected chest X-Ray images were used for evaluating the performance of content-based image retrieval. Image retrieval has been carried out based on the absolute difference between the encoded features of twin images obtained from the Siamese Convolutional Neural Network (SCNN). The retrieval performance is awe-inspiring as the Siamese network used for retrieval is a relatively shallow network. SCNN does not require resource-hungry training with huge samples as part of its underlying implementation characteristics. The execution time is also very encouraging as the simplicity of the method is concerned. The method achieves 94% average precision and 100% average reciprocal rank while rank = 5 has been considered. Till now, no work has been reported on content-based retrieval of COVID-19 chest X-Ray images. Thus, a comparative study of evaluation metrics and execution time requirements of similar work could not be provided.

This paper describes a method to reduce the torque ripple for the Wound Field Synchronous Motor, which does not use a permanent magnet. When a WFSM is used in an Integrated Starter Generator system, it must have a higher power density than other automotive motors in order to satisfy the size constraints and required power. An increase in the power density creates a magnetic flux saturation in the rotor, and this soon becomes the cause of an increase in the torque ripple of motor. An increase in the torque ripple can degrade the Noise Vibration Harshness characteristics of automotive by creating vibration and noise in the engine start-up mode, in which the maximum torque is generated in an ISG system. This paper proposes a method of reducing the torque ripple via a design that uses a flux barrier model in the WFSM’s rotor. The Response Surface Method is used to optimize the flux barrier model, and Finite Element Method is used to to verify the torque ripple reduction.

The ride comfort, driving safety, and handling of the vehicle should be designed and tuned to achieve the expectations defined in the company’s design. The ideal method of tuning the characteristics of the vehicle is to modify the bushings and mounts used in the chassis system. To deal with the noise, vibration and harshness on automobiles, elastomeric materials in mounts and bushings are determinant in the automotive components design, particularly those related to the suspension system. For most designs, stiffness is a key design parameter. Determination of stiffness is often necessary in order to ensure that excessive forces or deflections do not occur. Many companies use trial and error method to meet the requirements of stiffness curves. Optimization algorithms are an effective solution to this type of design problems. This paper presents a simulation-based methodology to design an automotive bushing with specific characteristic curves. Using an optimum design formulation, a mathematical model is proposed to design and then optimize structural parameters using a genetic algorithm. To validate the resulting data, a finite element analysis (FEA) is carried out with the optimized values. At the end, results between optimization, FEA, and characteristic curves are compared and discussed to establish the correlation among them.

The automotive industry has striven for fuel economy and resource efficiency through the deployment of powder metallurgy (PM) manufacturing processes for few decades. However, PM technology for transmission gears is currently only used at a small scale within the automotive industry. This is mainly due to: its shortcomings in material properties and performance gaps for final parts; lack of advancement in pressing technologies (dimensional limitation); lack of data availability (e.g. on materials, load capacity calculations; gear design experimental confirmation); premature failed attempts on PM gears; economics of scale and large initial capital investments. This article reviews the current state of the art of PM gear manufacturing technology highlighting an important gap in technical and financial data availability for PM gear economic analysis. Thus, this study seeks to give some empirical evidence of the economic aspects of PM gear manufacturing. Data availability is still the major challenge with respect to PM cost calculations thus further studies are needed to quantify both the economic and non-economic benefits e.g., sustainability, noise vibration harshness (NVH) of PM adoption.

Detecting damage in composite materials is significantly important for the utilization of them. The paper investigates the use of the experimental part of modal analysis method to indicate damage presence in FRP specimen. The study goal is to examine the efficiency of the method to detect damage by investigating the noise, vibration and harshness (NVH) behaviour of damaged and undamaged fiber glass reinforced polymer specimen with simple geometry. A defect is generated artificially in the test specimen in order to visualize the difference in the dynamic parameters such as natural frequencies, modal damping, and mode shapes between the damaged and undamaged one. The results reveal the change of the NVH characteristics of the part during the damages leading to show the sensitivity of the experimental modal analysis for damages.

This chapter describes the basic material selection considerations for designing lightweight vehicle body. It also includes design considerations for stiffness, strength, fatigue durability, crashworthiness, and noise, vibration, and harshness of body structure and body panels. Optimization processes for lightweight designs are briefly described.

The necessity to improve the Noise Vibration Harshness (NVH) performance and, in particular, to reduce the flow noise produced by turbulent exhaust gases is requiring automotive manufacturers to optimize Internal Combustion Engines (ICE) exhaust systems from the early design phases. Computational Aeroacoustics Analyses (CAA) can be seen as a promising tool to support engineering design and optimization, enabling the evaluation of system performance and allowing the selection of effective noise reduction strategies.

The noise, sound pollution, and harshness are steadily increasing alarmingly from various vehicles such as lorries, vans, cars, and buses. It is considered a significant concern in our modern life due to the long-term harmful effect on human health. The excessive vehicular noise and sound pollution mainly affecting in specific areas of smart cities such as hospitals, educational institutes, various private/public organizations. As a result, people are suffering from neurocognitive problems. Therefore, controlling the sound pollution from vehicles are incredibly essential to mitigate health issues globally. However, minimal research was conducted by monitoring vehicular noise intensity in a smart city area using smart, reliable, and sophisticated technologies such as the internet of things (IoT) to mitigate these issues. This paper presents an enhanced intelligent IoT-enabled vehicular noise intensity monitoring system to protect the city dweller’s health by reducing sound pollution in the smart city. We are planned to propose an architectural framework using noise intensity measuring sensors, 360° Camera, 360° LIDAR, GPS (Global Positioning System) in the vehicle with IoT technology for monitoring individual vehicles and their nearby vehicles over the smart city. The proposed system can monitor real-timely vehicular noises and notify designated stakeholders (i.e., vehicle owner, city authority) promptly and stored in the cloud with valid proofs. The proposed system helps to develop an ideal vehicular noise monitoring system over the smart cities and the widespread significance of mitigating health problems that relate to sound pollution and increase public awareness.

This research focuses on wide speed range noise, vibration and harshness (NVH) performance comparison and optimization of different fractional slot concentrated winding permanent magnet synchronous machines (PMSM) for automotive application through a unit force response-based method of vibration prediction called vibration synthesis. Process verification is done for vibration synthesis through extensive testing of a 12 slot 10 pole (12s10p) PMSM before subsequent application for comparison of different PMSM designs. Most of the NVH comparison work available in the literature focus on single operating speed-based performance evaluation which is the drawback this work aims to remove. Different slot/pole combinations of PMSMs are compared in this work in regard to their NVH performances. Electromagnetic and/or mechanical impacts brought by one structural NVH performance improvement method is analyzed in detail using unit force response method, and subsequently, vibration synthesis is used to compare the NVH performances over the entire speed range of interest. This will offer a better understanding of different design modifications done for NVH performance improvement in electric machines.

Wide variety of road types like intersections, highways poses a real challenge to the computer vision algorithms. Hence, there is a need of efficient algorithm to detect the accident on road and also evaluate the severity of the incident. This can be used to improve the emergency services response time. The work demonstrated in this paper aims to develop such an algorithm by modifying existing CCTV surveillance system. In this work, the accident is detected by the dispersion in the motion field of the vehicles during collision. Motion field of the road is obtained from the optical flow of the video frames. The moving objects in the frames are segmented and tracked. The dispersion in the angle vector of the optical flow is derived for each of the moving object. The dispersion of angle vector for each object is monitored, and deviation of the same from the threshold is determined as an accident. The harshness of the accident can be found by the range of dispersion of the motion field. The algorithm developed here is capable of detecting accidents between any types of moving objects.

The various factors that affect ride comfort, including noise, vibrations and harshness (NVH) have been in focus in many research studies due to an increasing demand in ride comfort in the automotive industry. Vibrations have been highlighted as an important contribution to assess and predict overall ride comfort. The purpose of this paper is to present an approach to explain ride comfort with respect to vibration for the seated occupant based on a systematic literature review of previous fundamental research and to relate these results to the application in the contemporary automotive industry. The results from the literature study show that numerous research studies have determined how vibration frequency, magnitude, direction, duration affect human response to vibration. Also, the studies have highlighted how body posture, age, gender and anthropometry affect the human perception of comfort. An analysis was made of the consistency and inconsistency of the results obtained in the different studies. The deviations of the research results from real-world ride comfort in automotive vehicles were analyzed and divided into three groups: appreciable and consistent with industry results, appreciable and inconsistent with industry results and not appreciable in industrial results. The overall conclusion from this literature study was that there is much information available from laboratory studies regarding human response to vibrations, but there is a lack of studies that take into account all the different parameters that affect the overall ride comfort experience for automotive vehicle occupants.

Summary & ConclusionsThe development of an engine-cooling module (ECM) for an European carmaker faced a major blocking point. The stalemate concerned the design of the suspension rubbers separating the engine-cooling radiator (the ECM carrier) from the chassis. The development of an engine-cooling module (ECM) for an European carmaker faced a major blocking point. The stalemate concerned the design of the suspension rubbers separating the engine-cooling radiator (the ECM carrier) from the chassis. From the one hand, the damping rubbers had to be soft, in order to be compliant with noise, vibration & harshness (NVH) criteria – acoustic noise and vibration transmitted to the cabin. On the other hand, their softness would provoke such high amplitude response during shaker tests that the module carrier (the radiator) would fail at the early stage of vibration testing – a leakage was observed after 10 hours of the targeted 90 hours duration. New rubbers, designed for durability purposes, would fail to meet the NVH criteria. The project development team went through a double-faced dilemma: how to design rubbers with an acceptable trade-off between NVH and durability of the engine-cooling radiator, and how to find a quick and efficient way to validate the design in order to be compliant with vibration validation tests. Together with the customer, our company (automotive tier-1 supplier) established an iterative design optimization of the damping rubbers, based on the simultaneous feedback from the acoustic response and the durability predictions. The goal was to develop a strategy permitting a quick an effective criteria for damage estimation for each design proposed.

There is a growing interest in new sensing technologies and processing algorithms to increase the level of driving automation towards self-driving vehicles. The challenge for autonomy is especially difficult for the negotiation of uncharted scenarios, including natural terrain. This paper proposes a method for terrain unevenness estimation that is based on the power spectral density (PSD) of the surface profile as measured by exteroceptive sensing, that is, by using a common onboard range sensor such as a stereoscopic camera. Using these components, the proposed estimator can evaluate terrain on-line during normal operations. PSD-based analysis provides insight not only on the magnitude of irregularities, but also on how these irregularities are distributed at various wavelengths. A feature vector can be defined to classify roughness that is proved a powerful statistical tool for the characterization of a given terrain fingerprint showing a limited sensitivity to vehicle tilt rotations. First, the theoretical foundations behind the PSD-based estimator are presented. Then, the system is validated in the field using an all-terrain rover that operates on various natural surfaces. It is shown its potential for automatic ground harshness estimation and, in general, for the development of driving assistance systems., 26 pages

The technical specifications of electrified vehicles (xEVs) will drastically change the way future vehicles might sound compared to conventional vehicles with internal combustion engines (ICEVs). The electrified powertrain is responsible for a profoundly different profile in vibro-acoustical characteristics (NVH: noise, vibration, and harshness) and offers the opportunity to create specific sounds related to certain requirements and endorsing associations for increasing the user experience and aesthetic appreciation. The present study’s main aim was to evaluate the perceived emergence of the electric powertrain noise and its implications for perceived quality conveyed by it. Utilizing a sophisticated acoustic simulator presenting ambisonic 3D stimuli from eleven different electrified cars in four different driving scenarios, N = 65 participants evaluated the perceptibility of e-powertrain noise and perceived quality of the vehicle’s interior soundscape. We revealed the auditory modality as an integral part of assessing the product’s quality and gathered qualitative reference points for further investigations.

Materials play a fundamental role in defining the vibrational and acoustic characteristics of structures and their importance is even increasing because of the continuing demand for lightweight products. Carbon Fibre Reinforced Plastics (CRFP) components are becoming more and more popular because of their excellent mechanical properties but are unfortunately almost unable to dissipate energy. This is one of the reasons why their usage is limited to structural components and does not directly affect acoustic and vibrational response, which are among the factors responsible for harshness and comfort. In vehicles, for example, large panels of CFRP are as noisy as metallic panels so that this kind of lightweight structures is only used when a limited mass is of paramount importance, e.g. in racing cars. The chance of incorporating a damping material in the stacking sequence of CF layers that define a composite seems to be a viable solution to ameliorate the vibrational behaviour of composite materials. This configuration permits to cure the damping layers together with the resins, in order to obtain both free and constrained layer solutions. In this paper, the Oberst beam method has been chosen to determine the elastic modulus and loss factor of such materials, as a function of both frequency and temperature. Three nominally identical samples for each configuration have been tested in a temperature controlled environment, according to the Oberst beam test method. The effects of aging have been simulated by an accelerated standard procedure, with cyclically varying temperature and humidity for a total of 792 h (3 cycles x 264 h). The analysis of experimental data has been performed in the frequency domain by a least square fitting procedure, aimed at outperforming the simple half-power point method. An open source version of the fitting technique has also been implemented and can be obtained from the authors under the CC-by license.

Analysis of Noise, vibration and Harshness (NVH) of the car door was carried out, the door component is a very vital body in the passenger car, it not only provides safety against the outside obstacles which are disturbing driver and occupants and it also protects from wind and also offers aerodynamic effects while in motion, door will vibrate due to wind force and by the less strong weak reinforcement, this can be overcome by adding some Vibration Dampers. Initially numerical analysis is conducted for conventional car door for without and with viscoelastic damping material at free – free condition. In the next step, Experimental modal analysis is carried out for automotive car door for without and with viscoelastic damping at same condition. Natural frequencies and mode shapes were collected at both methods and compared together; Hence, it proved that component with viscoelastic damping material one was better than conventional one

© 2017 Elsevier Ltd The integration of the electric motor to the powertrain in hybrid electric vehicles (HEVs) presents acoustic stimuli that elicit new perceptions. The large number of spectral components, as well as the wider bandwidth of this sort of noises, pose new challenges to current noise, vibration and harshness (NVH) approaches. This paper presents a framework for enhancing the sound quality (SQ) of the hybrid electric powertrain noise perceived inside the passenger compartment. Compared with current active sound quality control (ASQC) schemes, where the SQ improvement is just an effect of the control actions, the proposed technique features an optimization stage, which enables the NVH specialist to actively implement the amplitude balance of the tones that better fits into the auditory expectations. Since Loudness, Roughness, Sharpness and Tonality are the most relevant SQ metrics for interior HEV noise, they are used as performance metrics in the concurrent optimization analysis, which, eventually, drives the control design method. Thus, multichannel active sound profiling systems that feature cross-channel compensation schemes are guided by the multi-objective optimization stage, by means of optimal sets of amplitude gain factors that can be implemented at each single sensor location, while minimizing cross-channel effects that can either degrade the original SQ condition, or even hinder the implementation of independent SQ targets. The proposed framework is verified experimentally, with realistic stationary hybrid electric powertrain noise, showing SQ enhancement for multiple locations within a scaled vehicle mock-up. The results show total success rates in excess of 90%, which indicate that the proposed method is promising, not only for the improvement of the SQ of HEV noise, but also for a variety of periodic disturbances with similar features. ispartof: Mechanical Systems and Signal Processing vol:99 pages:478-503 status: published

Noise, vibration and harshness (NVH) as well as scuffing failure are the key design attributes of high-speed gear transmission. Unlike the traditional methods, this study desires to establish a new tribo-dynamic model for spur gear pair to predict the dynamic and tribological behaviors within a wide rang of speeds under various conditions. Therefore, a multiple degrees of freedom discrete dynamic model is combined with an infinite line contact thermal elastohydrodynamic lubrication (EHL) model to investigate the interactive mechanism between the dynamics and tribology, using an iterative calculation program which integrates the Runge-Kutta method and the multigrid method. Serious deviations are found in high speed condition by making a comparison between the quasi-static and tribo-dynamic simulation results, validating the importance of tribo-dynamic model. Numerical results show that the proposed model can provide guidance for engineering practice of high-speed gear design.

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.

The vehicle door seal strip has complex dynamic characteristics and is a critical component in the vibration and sound transmission of the vehicle system. However, in noise, vibration, and harshness (NVH) analysis, the seal strip is commonly simulated as a linear spring model, which results in inaccurate vibration and sound prediction. Thus, it is necessary to propose an alternative model, which allows characterising the complex dynamic behaviour of the seal strip accurately. In the present study, an overlay material model of rubber was encoded and embedded in ABAQUS with the UMAT subroutine. The overlay model was used in a seal strip finite element model validated by the quasi-static and dynamic measurements. By analysing the effects of frequency, amplitude, and pre-compression on the dynamic stiffness of a seal strip, an equivalent NVH model consisting of spring and damping elements was proposed. The proposed model was validated by comparing the simulated mode and vibration transfer function results with experimental ones. Using the spring model, the deviations of vibration transfer function with the experimental results are 37% and 8.3% at the first and second peaks, respectively. The corresponding deviations are only 4.6% and 2.6% employing the proposed model, demonstrating that the proposed model provides higher accuracy than the spring model. With the assist of the proposed model for vibration transmission analysis, a typical door vibration problem was successfully addressed, which proved the effectiveness of the equivalent model in engineering practice.

Tire vibration characteristics influence noise, vibration, and harshness. Hence, there have been many investigations of the dynamic responses of tires. In this paper, we present new formulations for the prediction of tire tread vibrations below 150 Hz using a three-dimensional flexible ring-based model. The ring represents the tread including the belt, and the springs represent the tire sidewall stiffness. The equations of motion for lateral, longitudinal, and radial vibration on the tread are derived based on the assumption of inextensional deformation. Many of the associated numerical parameters are identified from experimental tests. Unlike most studies of flexible ring models, which mainly discussed radial and circumferential vibration, this study presents steady response functions concerning not only radial and circumferential but also lateral vibration using the three-dimensional flexible ring-based model. The results of impact tests described confirm the theoretical findings. The results show reasonable agreement with the predictions.

This paper deals with numerical investigation of the single–stage gearbox housing dynamic behaviour during low-torque operating conditions. First the modal properties of the key components are derived and experimentally evaluated on the physical model. Next the main simulations are performed in MBS (multi-body system) software, the model is based on the open loop test rig. The computational methods aim to represent dynamic behaviour of the gearbox housing key parts with respect to NVH parameters evaluation, which is done by surface normal velocity amplitude. The presented part of investigation also deals with different kind of input speed variability. The simulation results show that the variable input speed has strong influence on dynamic behaviour.

The leaching process is an important component in hydrometallurgy. A predictive model of the leaching rate lays the foundation for soft measurement and process optimization, and data collection is the key in such a modeling effort. However, because of the complexity and harshness of leaching process, data can only be collected sparsely, which results in data deficiency in the modeling process. Therefore, data imputation before modeling seems to be extremely significant. In this paper, expectation maximization imputation based on the Gaussian mixture model (GMM-EM) and multiple imputation (MI) are respectively applied to perform missing data imputation for leaching process under different data loss rates and data loss patterns, and then the imputation performances are evaluated. Simulation experiment results have shown that GMM-EM and MI both have advantages with regard to data imputation. Therefore, MI based on GMM (GMM-MI), which combines the advantages of GMM and MI, is proposed in this paper. The effectiveness of GMM-MI is verified by a series of simulations.

Models of varying degree of sophistication are used in vehicle dynamic studies. For ride comfort, Kelvin–Voigt arrangement is preferred and for impact harshness analysis, a relaxation-type suspension model, Zener or Maxwell type is used. The nonconsideration of relaxation-type models in ride comfort studies can result in significant errors for frequencies below ∼30 Hz. The object of the paper is to show the influence of the series stiffness on the effective suspension damping both experimentally and numerically. A frequency domain analysis of two-degree of freedom Zener quarter car model is performed to find the complex relation between effective damping coefficient and the limiting value of damping ratio for a given series stiffness. The nonlinear relation between shock absorber damping and the natural frequencies is clearly illustrated. A novel four-post rig set-up is used to validate the results by measuring transmissibilities, giving damping ratios for varying shock absorber settings. A closed form solution, based on a simplified partial model, of optimal damping coefficient, which is a nonlinear function of stiffnesses, shows good agreement with numerical simulations of the complete system. The nonlinearities in shock absorbers also influence the outcome. These findings can be a great value at early design stage.

Despite the harshness of the space radiation on satellite electronic components, some Commercial Of The Shelf (COTS) can sustain such harsh environment. Thus, the low-cost advantage of the COTS can be utilized given that these electronic components meet the technical design requirements of the targeted satellite subsystem. Because of the complexity of microcontrollers and their various integrated functionality, they present a hardness assurance challenge. A careful technique was followed in analyzing the space radiation effects. Then rigorous tests should be conducted to test the performance of the candidate microcontrollers under these effects. This paper presents the predicted dose depth curve and the total ionizing does test results for a commercial ARM microcontroller for Low Earth Orbit (LEO) satellites. Such test results help estimate the effect of space environment on the microcontroller and decide if such microcontroller is an accepted candidate for LEO missions or not.

Jounce bumpers in automotive suspension are key components that can improve the noise, vibration, and harshness performance of entire vehicle. Traditional jounce bumper made of polyurethane usually cannot satisfy the mechanical performances required by noise, vibration, and harshness optimization. In addition, the application of hyperelastic material influenced the efficiency and reliability of numerical calculations of polyurethane jounce bumper. In this paper, an engineering negative Poisson’s ratio structure was introduced and applied on the jounce bumper. The negative Poisson’s ratio jounce bumper can be mainly defined by few structure parameters. The finite element analysis of the negative Poisson’s ratio jounce bumper was conducted applied explicit method. The influences of loading velocity and material densities on computational time and numerical results were researched. The results indicated that enlargements of material densities and loading velocity can improve the computational efficiency and have limited influence on reliability. Furthermore, a negative Poisson’s ratio jounce bumper prototype was manufactured and tested to verify the numerical results. It was proved that the finite element analysis of the negative Poisson’s ratio jounce bumper was reliable both in load–displacement curve and deformation shapes. Compared to the traditional jounce bumper, the negative Poisson’s ratio jounce bumper can achieve similar mechanical behavior but with a smoother load–displacement curve, which is beneficial to the vehicle’s noise, vibration, and harshness performance.

This paper presents certain considerations related to noise, vibration and harshness issues on modern motor vehicles. The first, practical aspect was used toward structuring of the acquired knowledge and relationships, required for proper problem diagnosis. On the other hand, advanced signal analyses are considered. The influence on human body is processed and certain noise and vibration analyzers are presented. This synergy of scientific and applicative approach represents a basis for further research related to this important automotive branch.

Concrete workability, quantified by concrete slump, is an important property of a concrete mixture. Concrete slump is generally known to affect the consistency, flowability, pumpability, compactibility, and harshness of a concrete mix. Hence, an accurate prediction of this property is a practical need of construction engineers. This research proposes a machine learning model for predicting concrete slump based on the Least Squares Support Vector Regression (LS-SVR). LS-SVR is employed to model the nonlinear mapping between the mix components and slump values. Since the learning process of the LS-SVR necessitates two hyperparameters, the regularization and the kernel parameters, the grid search method is employed search for the most desirable set of hyperparameters. Furthermore, to construct the hybrid model, this research collected a dataset including actual concrete slump tests from a hydroelectric dam construction project in Vietnam. Experimental results show that the proposed model is capable of predicting concrete slump accurately.

The automobile industry is actively developing hybrid electric vehicle (HEV) or electric vehicle (EV) with electric motors to overcome the limitations of conventional internal combustion engine cars. This has the advantage of significantly improving the fuel economy of existing internal combustion engine cars, but it can be annoying to the driver by creating a whine noise in the new frequency range. This paper proposed a new design concept based on the electromagnetic shape optimization to improve the noise, vibration and harshness (NVH) performance. The new design was optimized using the response surface methodology (RSM). As a result, NVH have been improved dramatically as well as the motor efficiency with the virtual slot technology. The motor was prototyped and confirms the cogging torque reduction. Moreover, the whine noise level was satisfied beyond the goal. The design has been patented to obtain the technical excellence.

Structural dynamic modification (SDM) techniques are important in structural optimisation of the system to modify the dynamics behaviour of the structure. It can be implemented by utilising the dynamic test data to alters the dynamic behaviour of the structure. However, there are some concern in the design process in which the undesirable mode shapes movement of structure are occurred along side with desired natural frequencies. Therefore, the SDM technique can be used as to varying the predicted dynamic behaviour of structure to solve noise, vibration and harshness problems (NVH). In order to be well predicted the modified dynamic behaviour of structure, the optimisation method via finite element (FE) model updating is used to obtain a reliable and accurate unmodified FE model. The main goal of this research is to change or altered the mode shapes movement of the mild steel bar structure due to the mass modification without shifting the natural frequencies away from unmodified value. In this research, the FE model of the mild steel bar structure was constructed using MSC software and the predicted dynamic behaviour were compared with the experimental modal analysis (EMA) data. The measured data was obtained using an impact hammer testing and roving accelerometers under free-free boundary conditions with data were extracted from LMS SCADAS software. Then, reconciliation process via FE model updating method is carried out in order to reduce the inaccuracy of initial FE model based on the measured data where the initial error has been reduced from 24.81 percent to 7.71 percent. Finally, the updated FE model was used for SDM technique using mass modification. The results reveal that the mode shapes of the structure can be change by manipulating the mass. It is agreed that by adding a reasonable mass with a right position to the structure the mode shapes can be change without shifting the natural frequencies away from unmodified values.

Legislation drives the automotive megatrend to reduce fuel consumption and CO2 is resulting in small high output 3 and 4 cylinder engines. While customers have raised expectations on driving comfort, the smaller high output engines have inherent vibration noise, vibration and harshness (NVH) issues. Thus gear rattle in mass balance systems, cam gears, pump and accessory drives is an NVH issue. The most common approach is to use a split (scissor) gear assembly; the solution is complex, high in cost and heavy. High performance polymer injection molded net shape gears made from VICTREX® PEEK have gained growing attention and acceptance as cost effective, low mass and highly efficient solution to significantly reduce NVH in engine related application areas like mass balancer, cam and pumps. This paper presents test data done with validation customers and independent research institutes. It also references and discusses technical publications at SAE and VDI. With a successful case study it further it demonstrates the benefits of a net shape polymer gear solution offering a 3 dB (~50%) improvement in NVH, a 68% weight reduction resulting in 78% reduction of the moment of inertia and therefore 9% less torque required to operate compared to a cast iron gear set.

An accurate prediction of the dynamic stiffness of the rubber isolator is critical to vehicle noise, vibration, and harshness performance. However, it is rather difficult due to the fact that it is simultaneously influenced by their application environment factors such as frequency, amplitude, and preload, etc. So far, related studies are still few. In the present study, taking the typically used chassis rubber bushing as the research object, a series of dynamic stiffness tests for rubber bushings was conducted under different frequencies, amplitudes, and preloads conditions. The Zener model was adopted to consider the frequency dependence, and an operation coefficient was introduced to quantify the amplitude and preload dependence. In order to obtain the actual dynamic stiffness of such rubber isolator, a modified calculation method considering the frequency, amplitude, and preloads dependence was proposed. The effectiveness of the proposed method was validated through comparing the accelerations synthesized by the transfer path analysis method with experimentally measured values. Compared to the traditional approach, the response can be more accurately calculated by the proposed method. It was further applied in solving the abnormal door vibration problem in a typical SUV. The vibration contribution analysis shows that the reasons for the door vibration problem caused by excessive transmitted forces at the rear stabilizer bar bushing in the x-direction and z-direction. A solution based on the analysis of the influence of corresponding bushing dynamic stiffness on target acceleration was therefore adopted to solve the abnormal door vibration problem effectively.

Hybrid electric vehicles (HEVs) have become increasingly popular due to their high fuel economy performance. HEVs typically fall into three categories according to their powertrain configuration, namely serial, parallel, and power-split hybrid. All these configurations use small internal combustion engines (ICEs), which can suffer from high torque fluctuations detrimental for noise, vibration and harshness performance. This paper introduces a novel architecture of hybrid electric powertrain systems (patent pending) which suppresses torque fluctuations and carries out the functionality of hybrid driving. This new hybrid architecture conceptually lies between a serial and a power-split. The new system uses an ICE and two electric machines, including one with a rotating stator, and has the functionalities of existing hybrid powertrains, including transmission, boost, regenerative braking. The paper presents a model for this new powertrain, and a unique controller implemented in MATLAB Simulink®. A specially designed ruled-based multi-state controller is included in the model to achieve control and enhance fuel economy. Results of drive cycle simulations show the systems performance including torque fluctuation suppression and great fuel economy.

In this work the dynamic substructuring approach was applied to a noise, vibration and harshness problem within the automotive engineering field. In particular, a noise, vibration and harshness analysis was carried out on the body-in-white structure of a passenger car. The work focuses on the theory of component mode synthesis. Two component mode synthesis reduction methods, namely the Craig–Bampton method and the Craig–Chang method, were applied to the body-in-white structure of the Volvo V40. The influences of various parameters were investigated. In particular, the effect of the reduction basis on the response accuracy and on the reduction time was studied. Moreover, the effects of the connection properties between different parts of the model were examined. The simulation times of the reduced models and of the full finite element model were compared. The results showed that the Craig–Chang method performs better when the modes are retained for up to one and a half times the maximum frequency response studied. Additionally, the Craig–Chang method gives a very accurate representation of the system dynamics even when connections with a low stiffness are used. Finally, it is possible to reduce the simulation time by up to 90% if component mode synthesis methods are used instead of the full finite element model.

Establishing a precise system level model for transmission system is quite necessary and feasible for today’s computer technology. Taking into account of the exact parameters and actual working condition, an accurate model for a new deep hybrid transmission with compound planetary gear set is constructed, which in consideration of the gravity and centrifugal effect. The system level model contains the gears, shafts, bearings, clutches, electric motors and the housings. Few studies are found to investigate structure influence in system level for noise, vibration and harshness performance. Validation for the simulation results with test in three typical working conditions is carried out, which shows a quite well agreement. Furthermore, some parameters for this compound planetary gear set are investigated. The results show that for radial clearance between the ratchet and ring gear the smaller the better, while the axial clearance between the ratchet and ring gear requires cautious consideration to realize a...

Jounce bumpers in automotive suspension can absorb impact energy and improve Noise, Vibration and Harshness (NVH) performance of entire vehicle. In this paper, a negative Poisson's ratio (NPR) structure was introduced and applied on the jounce bumper. The NPR jounce bumper can be primarily described by few parameters and is convenient for design, analysis and optimization. Three NPR jounce bumper prototypes were manufactured and tested. The test results of prototype 1 indicated that the NPR jounce bumpers had excellent viscoelasticity characteristic to absorb impact energy owing to its high damping. Compared with traditional jounce bumper, the NPR jounce bumper can achieve similar mechanical behavior but with a smoother load-displacement curve, which is beneficial to the NVH performance. Moreover, numerical calculation was conducted. Its results were fairly reliable for the prediction of mechanical behavior of NPR jounce bumper. The numerical results implied the stress concentration areas and the displacement of failure. The deformation shapes of NPR jounce bumper were also discussed. Finally, prototypes 2 and 3 manufactured from 3D printing technology were tested to explore the possibility of the application of 3D printing technology on NPR structures. Keywords: Negative Poisson's ratio, Jounce bumper, Uniaxial compression, Numerical calculation, 3D print

Powertrain Center, Hyundai Motor Company(Received May 3, 2016; accepted May 23, 2016)ABSTRACT: A systematic development process for the low noise FEAD (Front End Accessory Drive) system is presented by combining CAE (Computer Aided Engineering) and the experimental rig test. In the estimation of the belt drive noise, two main difficulties arise from the high non-linearity due to the stick-slip contacts on the interfaces of the belt and pulleys, and the interaction of the belt drive system with the powertrain rotational parts. In this work, a recently developed analysis method of the belt drive has been employed considering powertrain rotational dynamics. As results, it shows good correlation with the vehicle tests in various operational modes. The established model has been employed to validate the new design improving the stick-slip noise of the problematic FEAD system. Furthermore, the best proposal of FEAD system in terms of functionality [NVH (Noise, Vibration and Harshness), fuel economy, cost. etc.] has been suggested in the concept design stage of new engine through this presented methodology.Keywords: FEAD, Belt dive, Belt layout, Stick-slip, NVH, Fuel economyPACS numbers

BACKGROUND: One of the major aims in the treatment of patients with heart failure (HF) is symptom relief and an improvement in the health-related quality of life (HR-QoL). The perception of impairments due to HF may differ between patients. A knowledge of the prevalence and perceived harshness of impairments due to HF is essential in providing personalized care on a patient level, in optimizing care on a population level and in finding the most appropriate patient-reported outcome for clinical trials. AIM: The aim of this study was to explore the prevalence and perceived harshness of impairments due to HF and the relation between perceived harshness and HR-QoL in patients with HF. METHODS AND RESULTS: The prevalence of impairments due to HF was assessed using items of the Minnesota Living with Heart Failure Questionnaire and the degree of perceived harshness was assessed using a structured self-assessment. A total of 100 outpatients (mean±SD age 70±9 years, 71% men) from an HF outpatient clinic were included. The prevalence of impairments was between 18 and 77%. The most prevalent impairments included tiredness and impairments in physical activity. Impairments that were frequently perceived as severely harsh included tiredness (67%), dyspnoea (57%) and impairments in physical activity (55%). Corrected item-total correlation (range 0.10-0.59) showed that tiredness (r=0.54) and impairments related to resting (r=0.59) and to participation in physical (r=0.52) and social (r=0.55) activities contributed highly to the sum-score of the Minnesota Living with Heart Failure Questionnaire. CONCLUSION: Highly prevalent impairments are not by definition perceived as severely harsh by patients with HF and do not contribute to the overall HR-QoL except for the impairments tiredness and working around the house/yard. These insights are important in providing personalized and optimized care for patients with HF. Funding agencies: Dutch Ministry of Health, Welfare, and Sport

Disc brake squeal refers to the high-frequency noise caused by self-excited vibration induced by the friction force between discs and pads. It has received considerable attention over decades, as customers have come to increasingly demand less noise, vibration and harshness of vehicles. The vibration of the disc, which is considered to be one of the main sources triggering squeal, is classified as either inplane (IP) or out-of-plane (OP). Substantial effort has been made to investigate and mitigate the squeal induced by the OP vibration of the disc. Meanwhile, there is still no effective remedy for the squeal related to the disc IP vibration, despite numerous investigations have been made to suppress it. Consequently, this paper focuses on the disc IP vibration related squeal. A squeal experiment which is developed for measuring and recording squeal signals is introduced. The squeal signals include acoustic signals of squeal and acceleration signals of main components in a disc brake system. Furthermore, natural frequencies of the main brake components are confirmed using experimental modal analysis. General time-frequency-energy characteristics of the squeal signals are first presented by using results of basic Fourier transform-based signal processing methods. Subsequently, more detailed frequency and energy features of those non-stationary and nonlinear squeal signals are illustrated based on decomposition results of the ensemble empirical mode decomposition and the Hilbert transform. The resultant figures indicate that the recorded high-frequency squeal is mainly caused by the disc IP circumference vibration. Furthermore, it is inferred that the lower frequency component (with higher energy), which becomes the predominant component of the squeal phenomenon, is induced by the higher frequency component (with lower energy generated) firstly.

This paper advances a system-simulation based universal modelling approach for NVH-simulation of electric drives. The main idea is to use commercial FE-tools for model parametrisation and implement generic reduced electrodynamic and acoustic models in a system-simulation environment. The NVH-calculation itself is done in a system-simulation framework, which can be easily coupled with control and machine models for electric drives. The proposed approach is worked out in detail. As a first example, the simulation procedure is performed for an outrunner traction drive of electrified foldable scooters.