Vehicle Noise, Vibration And Harshness Research Articles

Preface

About the conference International Conference for Acoustic and Vibration Engineers (NVHH 2023) is the first edition of the biennial NVHH conference series on acoustics, structural dynamics and NVH (Noise Vibration and Harshness) organized by the Budapest University of Technology and Economics, the University of Győr, and the Hungarian Chamber of Engineers in close cooperation with industrial partners. The goal of the conference is to provide an international forum for acoustic, vibration, and NVH engineers, researchers, and professionals to share their contributions in the fields of experimental as well as numerical acoustics, vibroacoustics, vehicle NVH, interior acoustics, and entertainment system development. The conference caters to both academicians and professionals, therefore state-of-the-art university research and cutting-edge industrial innovation will be presented side by side, followed by social gatherings that promote the exchange of information and nurture fruitful cooperations between the various fields of the profession. NVHH 2023 in numbers The conference hosted 112 participants from 9 European countries, presenting 38 technical or scientific papers in 8 sessions, complemented by 4 plenary lectures. 9 professional exhibitors contributed to the industrial relevance.List of Conference Chairs, Keynote and plenary lectures, Organizing Committee, Scientific Committee are available in this Pdf.

Research on the Design Method of Pure Electric Vehicle Acceleration Motion Sense Sound Simulation System

Due to the emerging trend of energy conservation and emission reduction around the world, the new energy vehicle industry has achieved rapid development. However, there are new challenges regarding vehicle NVH(noise, vibration, and harshness). When a pure electric vehicle is being driven, the inside of the vehicle is relatively quiet, which cannot bring the driver sound feedback reflecting the change of the vehicle state. In order to solve this problem, this paper studies the design method of a sound simulation system for acceleration motion in pure electric vehicles. In this paper, the motion characteristics of automobile engine acceleration sound, sound signal analysis and processing, subjective evaluation of sound quality, and sound synthesis strategy are studied. By reading the vehicle running state data on the CAN bus of pure electric vehicles, the goal of engine motion sense sound simulation during vehicle acceleration is achieved. This helps to enhance driving feedback and improve user driving experience.

Vehicle road noise prediction using component-based transfer path analysis from tire test-rig measurements on a rolling tire

The current trends in the automotive industry toward electric vehicles are creating increasing interest on methods to quantify and predict the noise, vibration and harshness (NVH) behavior caused by road noise, as well as secondary noise sources. In this regard, component-based TPA (Transfer Path Analysis) has been recently explored. It is a powerful methodology allowing for a virtual prototype vehicle NVH prediction starting from independent sources and component models. The aim of this paper is to analyze the potential of the component-based TPA in the context of road noise. This methodology, on one hand, allows the tire manufacturers to characterize their tires on a tire test-rig independently of any vehicle and, on the other hand, enables the automotive OEMs to perform the prediction of the full system vehicle behavior starting from the test-rig measurements. However, some challenges are still hindering the application of the methodology in this context. In this regard, all the component-based TPA methodology steps are investigated in this work. A slick tire, selected for this analysis, is characterized on a test-rig by a set of blocked forces, which only depend on the source. The uncoupled tire and vehicle are experimentally characterized through the measurement of their frequency-response functions (FRFs) under a static load condition. Frequency Based Substructuring (FBS) is applied to these substructures in order to synthesize the coupled vehicle FRFs. Both rear tires are coupled to the vehicle using this approach. Finally, the vehicle road noise is predicted by propagating one of the tires’ blocked forces through the synthesized full vehicle FRFs in a modular approach. The method is validated by comparison with direct vehicle measurements. Transferability of blocked forces is also assessed by direct comparison between blocked forces estimated on vehicle and test-rig. Importantly, the rolling effect is identified and considered in a direct propagation process, analyzing its implications in the vehicle noise prediction. This paper also intends to serve as a guideline to industrialize the experimental and processing steps.

Multi-objective optimization of magneto-rheological mount structure based on vehicle vibration control

Considering the influence of mount structure parameters on the quality of vehicle noise, vibration and harshness (NVH), a multi-objective optimization method of the magneto-rheological (MR) mount based on vehicle vibration control was proposed. A lumped parameter model was used to establish the relationship between the structure parameters of the MR mount and the NVH performance of the vehicle. Considering the influence of current on the magneto-rheological fluid viscosity and flow rate in damping channel, the dynamic characteristics of MR mount was obtained by the lumped parameter model. Then, a 10 degrees of freedom (DOF) vehicle model with MR mounting system was established. Finally, a co-simulation optimal platform was developed by the ISIGHT, MATLAB, and ANSYS software, and the non-dominated sorting genetic algorithm II was used to optimize the design of the mount magnetic circuit with the goal of improving the quality of vehicle NVH. The results showed that under the start/stop and the constant speed conditions, the root mean square values of vibration acceleration of the driver’s seat rail of the vehicle with the optimal design magneto-rheological mount decreases by 31.6% and 7.8%, respectively compared with the initial design mount, improved the ride comfort of the vehicle.

NVH Full Vehicle Development - Virtual Simulation Process for Low Frequency Structure-Borne Regions

<div class="section abstract"><div class="htmlview paragraph">NVH (Noise, Vibration and Harshness) is a key attribute in Vehicle development. Refined vehicle enhances customer’s perception and also the brand image. Most of the OEMS have well-articulated NVH Development process which is a part of the Product development Cycle (PDC). The need for such process is essential to identify the inherent weakness or threats at earlier stage. And so the mitigation process need not warrant deviation or protection of resources, which would be a bottleneck at later stage. NVH is complex phenomena which deals with structure borne and airborne sources. So a NVH compliant vehicle is the product of resources which includes the skilled manpower, process and computational infrastructure. The stress for NVH front loading has gained traction in Global OEMS, to deliver “First Time Right“ NVH products. Full Vehicle NVH (VNVH) simulation is one of the complex virtual methods, done to understand and mitigate the inherent weakness of the systems and integration. Evaluations are based on load cases which are designed to simulate RWUP (Real World Usage Profiles). This paper explains systematic - “Sub System to System” approach along with the application of Virtual methods on different phases of the low frequency NVH development of vehicle to reduce structure-borne NVH and deliver best in class product. The system and its performance discussed in various section are representative in nature due to confidentiality. Therefore the focus would be on understanding the trend of system performance and studies to enhance it.</div></div>

Study on Radiated Noise of a Panel under Fluctuating Surface Pressure Due to an Idealized Side Mirror

As traditional automobiles develop towards new energy vehicles, the noise, vibration and harshness (NVH) performance of automobiles is facing new challenges. Without the cover of the traditional engine noise and inlet and exhaust noise, the high-speed wind noise becomes more prominent. Thus, research on the calculation method of vehicle interior noise in high-speed driving condition is needed. However, vehicle body structure is complex, and the external excitation components are complicated. In order to analyze the method of predicting the vehicle interior noise at high speed, an idealized side mirror model is taken as the research object in this paper and the radiated noise of a panel under the fluctuating surface pressure (FSP) due to the idealized side mirror is studied. The FSP of the panel is first studied by the numerical simulations of incompressible and compressible flow field. For the incompressible flow field, the Corcos turbulent boundary layer (TBL) model is established to simulate the convective component and the boundary element method (BEM) is used to extract the acoustic component. Subsequently, the Corcos model coupling BEM method, the random modal force coupling BEM method and the deterministic modal force coupling BEM method are used separately to calculate the noise of the panel under the FSP. For the compressible flow field, the convective and acoustic component in the fluctuating pressure are separated by the wavenumber-frequency spectrum (WFS) method. The radiated noise of the panel under the FSP is calculated again by using the WFS, the method of random modal force and the method of deterministic modal force, respectively. Then, the computational time of the six methods of incompressible and compressible calculation is compared. Finally, a fast and accurate method of calculating the panel radiated noise under FSP is obtained by comparing the computational accuracy with the experimental results and combining the computational time: the method of incompressible random modal force. This method can be used to quickly and accurately analyze the vehicle interior noise at high speed, and to optimize the exterior protrusions and the vehicle sound package for improving the vehicle NVH performance at high speed.

Review of Hybrid Finite Element – Statistical Energy Analysis methods in vehicle NVH predictions

In the vehicle industry, the noise, vibration and harshness (NVH) characteristics of a car are becoming more and more important. In order to control these, it is necessary to know the sources and contributors to the interior noise level. This paper provide an overview of the state-of-the-art on predicting the NVH characteristics of fully trimmed vehicles in the mid-frequency gap between 400 Hz to 1 kHz. It is shown that for this frequency range, typically a hybrid FE-SEA method is used. This method provides a mixture of the advantages of the deterministic and statistical approaches. The first part of the paper introduces the method, followed by an overview of the different fields of usage in the vehicle industry. At the end of the paper, gaps in the knowledge are identified.

A generalized inverse cascade method to identify and optimize vehicle interior noise sources

The noise, vibration and harshness (NVH) emitted by a vehicle are very important to a customer's perception of the vehicle quality. A vehicle's NVH can be improved by considering the three following facets: the noise source, transfer path, and receiver. The identification and optimization of vehicle interior noise sources is crucial when attempting to reduce noise levels and improve sound quality. Although traditional methods, such as those utilizing sound pressure levels, nearfield acoustic holography, and transfer path analysis, can provide the magnitudes and contributions of noise sources, they cannot present specific methods for optimizing those noise sources. This study proposes a new method, the generalized inverse cascade method (GICM), to solve this problem. The GICM combines systems engineering with the interval optimization technique to identify and optimize vehicle noise sources. Applying the GICM to a decision problem involves the following three steps: (1) constructing the decision problem as a cascade tree; (2) developing a numerical model to quantify the cascade tree; and (3) solving the numerical model using the interval optimization method. A Volkswagen sedan is used in this study as an example, and a vehicular road test and subjective evaluation are implemented to record and evaluate the interior noise. The GICM, identifies potential abnormal interior noise sources, and a modified method is presented to optimize the abnormal noise sources by calculating the feasible intervals of design variables. A verification experiment shows that the vehicle interior noise is successfully optimized, thereby validating the proposed GICM.

Extraction of vibration behavior in conventional and electric drive two-wheeler using order analysis

Electrification of automobiles results in new and challenging characteristics of vehicle NVH (Noise, Vibration, and Harshness) and ride comfort. Optimized architecture of electric vehicles has been evolved for appropriate placement of electric power drives. This paper presents the experiments performed for order analysis technique to predict the vibrational behavior of conventional and electric scooters which was not used in 2-wheelers earlier and used for 4-wheeler noise predictions and for vibration analysis of rotating machinery. Vibrational analysis of source alone in conventional and electric two-wheelers carried out by order analysis and the result is presented through Campbell Diagrams to observe the critical orders along with the variation of the amplitude of vibration as a function of frequency. Target locations’ Vibration Dose Values (VDV) is calculated to assess rider comfort and is compared with the ISO 2631 standard. The higher amplitude of vibration has been observed at 23rd order for electric scooter while for conventional scooter it is noted at 8th and 16th order with reference to the wheel speed. Compared to the conventional scooter, electric scooter exhibits very low overall vibration level and range is away from human perception range resulting in good comfort.

Experimental and numerical techniques for lightweight vehicle sound package development

The use of lightweight structural materials poses great challenge to noise control of a vehicle. A new approach to sound package design in lightweight vehicles was developed to reduce vehicle interior noise level without addition of weight. This new approach relies on lightweight acoustical materials that provide superior sound absorption performance to reduce noise level at the source, e.g., inside engine compartment and near the tires. Vehicle NVH finite element analysis (FEA) models were used to develop the lightweight vehicle’s structural design to bring the lightweight vehicle’s low and mid frequency responses closer the baseline vehicle’s performance. Full vehicle SEA (statistical energy analysis) model was developed to evaluate the high frequency NVH (noise, vibration, and harshness) performance of a vehicle. This correlated SEA model was used for the vehicle sound package optimization studies to develop sound package design to improve lightweight vehicle’s acoustic performance. In this paper, the use of NVH CAE (computer aided engineering) simulations for lightweight vehicle design is presented to highlight the limitation and use of FEA and SEA in lightweight vehicle development.

Investigation on Technology of Automobile Vibration and Noise Reduction Based on Body-In-White Structure

The automotive body system is not only a source for directly radiating noise into the vehicle interior space, but also a key component for transmitting various vibrations and noise. The optimization of the modes for body-in-white has significant meanings for improving the reliability and NVH (Noise, Vibration and Harshness) performance of the whole vehicle. Based on the current situation that there is more severe interior vibration and noise problem occurring in driving for a light passenger vehicle, a hybrid modal analysis method combined with experiment and simulation methods is applied to investigate the vibration and noise characteristics of the whole vehicle body. By performing such modal analysis, the modal frequencies of the auto-body are improved effectively by strengthening the vibration sensitive regions in the body structure. The experiment for measuring interior vibration and noise levels under cruise condition is conducted to validate that the structural optimization for body-in-white has significant contribution for improving the whole vehicle NVH performance.

Design Object Planning of Vehicle NVH Performance Improvement Based on HOQ

Basing on the system engineering 7D design planning model included the seven aspects of contents: design ideas, design environment, design objective, design step, design content, design method and design quality assessment. Combined the 7D design planning with House of Quality (HOQ), the model of design objective planning model was presented. In the model the satisfied degree of customer was the optimization object. The customer needs were satisfied with the engineering characteristics. The customer needs were analyzed with the analytic hierarchy process. The correlation among engineering characteristics was considered through the improvement relation matrix. At the same time, each customer need was insured to improve with the limited resource. Contrasted with the general optimization model this design objective planning model took the correlation of engineering characteristics into account. This optimization model was applied successfully in the NVH (Noise, Vibration, and Harshness) improvement design of vehicle. The HOQ of NVH planning was established according to the four customer needs. The six engineering characteristics were confirmed corresponding to the customer needs. The results showed that the customer need degree achieved 75.53％. If the satisfied degree wanted to be improved the cost should be increased. In this design objective planning model the resource and technology were configured in reason. It could help the technician make the reasonable judgment.

A fast numerical formulation for simulating vehicle compartment acoustics

Vehicle noise, vibration and harshness (NVH) problems can be analyzed using numerical methods such as finite element and boundary element analyses that are generally complex and time consuming. In order to reduce the analysis time and calculation burden, this paper discusses the development, use and verification of an enhanced, simplified numerical acoustic cavity formulation for the analysis of vehicle NVH problems. The proposed simplified vehicle model can incorporate multiple acoustic cavities, such as an engine compartment, passenger compartment, and connecting bulkhead compartment, joined by several flexible panels. The damping matrix of the model is constructed from measured acoustic absorption data and panel properties. Utilizing this approach, both single-cavity and three-cavity models are created, different floor panel configurations are investigated, and transfer functions predicted by these models are compared with corresponding transfer functions from measured data. The comparison results show that the proposed simplified model can provide reasonable accuracy for the analysis and simulation of vehicle compartment acoustics.

Spectral-based multicoordinate substructuring model for vehicle noise, vibration, and harshness refinement

The success of vehicle NVH (noise, vibration, and harshness) refinement often depends on the ability to identify and understand noise and vibration transmission paths within the mid-frequency range, i.e., 200–1000 Hz, throughout the assembled structure. Due to the complexity of the dynamics in this frequency range, most modal or finite element-based methods do not possess the fidelity needed. To address this gap, a multicoordinate substructuring theory applying measured structural-acoustic and vibration spectra is applied. Three forms of substructuring formulation, namely the nondiagonal, block-diagonal, and purely diagonal coupling cases, are developed. The performances of these approaches are studied numerically, and the net effects of these coupling formulations on the predicted joint and free substructure dynamic characteristics, and system response, are determined. Conditions for applying the simpler coupler that can simplify the testing process and overcome computational deficiencies are also derived. When the measured data is noise contaminated, the singular value decomposition (SVD) algorithm is found to be quite helpful. Using an actual vehicle, a comprehensive analysis of the measured and predicted vehicle system responses is performed. The results are employed to develop an understanding of the primary controlling factors and transfer paths and to cascade system requirements to the substructure level.

New analytical method to evaluate the powerplant and chassis coupling in the improvement vehicle NVH

The design of an automotive powerplant mounting system is an essential part in vehicle safety and improving the vehicle noise, vibration and harshness (NVH) characteristics. One of the main problems encountered in the automotive design is isolating low frequency vibrations of the powerplant from the rest of the vehicle. The significant powerplant mass makes the choice of frequency and mode arrangements a critical design decision. Several powerplant mounting schemes have been developed to improve NVH properties concentrating on the positioning and design of resilient supports. However these methods are based on decoupling rigid body modes from a grounded powerplant model which ignores chassis and suspension system interactions. But it cannot be stated that decoupling the grounded rigid body modes of the powerplant will systematically reduce chassis vibrations. In this paper, a new analytical method is proposed to examine the mechanisms of coupling between the powerplant and the vehicle chassis and subsystems. The analytical procedure expands the equation of motion of the vehicle components to such that a domain of boundary conditions used in the 6 degrees-of-freedom powerplant mounting model can be defined. An example of this new procedure is given for improving NVH chassis response at idle speed using the torque roll axis decoupling strategy.