Browse Topic: Harshness
Noise, Vibration, and Harshness (NVH) performance is critical in the automotive development process, yet identifying the true root causes of unwanted dynamic behavior remains a challenge in full vehicle or system-level finite element (FEM) models. This work demonstrates how Frequency Based Substructuring (FBS) provides an efficient framework for understanding NVH phenomena and facilitates new root cause analysis (RCA) types and processes. To begin, we prove the numerical accuracy of the FBS algorithm deployed in the presented investigation by comparing its results with those obtained with superelements and without substructuring. We point out that because the used FBS process starts with a modal representation of the components rather than their frequency response functions (FRF) a different class of RCA type becomes available. Then we introduce new RCA types starting with an analysis named Modal Influence (MI) that reveals the effect of the modes of any component on a certain response. Its key characteristic is that MI analysis is not restricted to the response component opposite to the well-known modal participation factors. Finally, a second novel analysis type is introduced, an advanced variant of Transfer Path Analysis (TPA). While standard TPA assesses the paths between only two system components, the new Expanding TPA is a multi-step process that identifies the most critical path across all components in a fully automated way.
Vehicle electrification and accelerated development cycles create a need for virtual Noise, Vibration and Harshness (NVH) development tools which are fast, precise and, seamlessly interchangeable between development sites, suppliers and OEMs. Component-based Transfer Path Analysis (C-TPA), standardized in ISO 20270:2019, enables independent component characterization and integration with virtual models to predict sound and vibration in new assemblies, referred to as Virtual Prototype Assemblies (VPA). However, conventional measurements are labor-intensive, typically restricted to a small number of samples, and overlook production variability. This paper introduces a fully automated, ISO 20270-compliant C-TPA system for non-rigid test benches, featuring a pre-instrumented test fixture with multiple vibration shakers and sensors automatically linked to a data acquisition system for immediate processing. Components can be characterized within minutes, with blocked forces directly integrated into a VPA workflow, replacing time-intensive in-vehicle testing with a repeatable, operator-independent bench procedure. A case study on an automotive steering system demonstrates the method’s accuracy, repeatability, and efficiency, along with its ability to predict realistic interior sound pressure levels and capture production variability, enabling robust virtual NVH evaluation early in the development cycle.
Recent advancements in system-level NVH (Noise, Vibration, and Harshness) development methodologies have improved target cascading and enabled more efficient system-level optimization. Dynamic substructuring facilitates the virtual integration and modification of multiple subsystems and the prediction of changes in overall transfer functions. In practical automotive applications, advanced frequency-based substructuring has been applied to virtually modify system parameters, such as mass and stiffness, at multiple points in a target system, allowing prediction of the resulting effects and optimization of parameter changes without physical intervention. This study extends the methodology by introducing an enhanced substructuring approach capable of addressing not only basic parameter modifications but also large-scale structural changes. The proposed process involves identifying the characteristics of a base system assembly and a target subsystem, decoupling the subsystem from the assembly, incorporating structural modifications, and predicting the resulting transfer function changes. The method was validated through two complementary workflows: a fully experimental test-based workflow and a hybrid workflow. The test-based workflow demonstrated the reliability of substructuring operations, decoupling and coupling, by experimentally evaluating the base assembly, the original subsystem, and the structurally modified subsystem. The hybrid workflow replaced the experimental subsystem models with finite element models, thereby demonstrating the feasibility of substructuring numerical subsystem models with a physical system assembly. Together, these workflows are applied to one of automotive suspension subsystems, cross-member, which can establish the accuracy, flexibility, and practical applicability of the proposed method in supporting system-level NVH development and structural optimization.
The virtual development of Electric Drive Modules (EDMs) for Battery Electric Vehicles (BEVs) requires proven and predictive methodologies. One part of the development investigates the vibro-acoustic assessment for the low- and high-frequency ranges within the targeted operating range. The efficient use of such a methodology requires an understanding of the accuracy and validity of the achievable results, as well as the derivation of suitable improvement measures for goals that have not been achieved. The use of reference data from experimental investigations and a detailed root cause analysis (RCA), to directly link a specific response and behavior to the excitations, modal content, and transfer functions, is an essential and non-trivial part of the methodology development. This paper describes the development of such a methodology using the example of a new EDM virtual model for Noise, Vibration and Harshness (NVH) analysis, including the simulation approach, validation, and evaluation procedure. It discusses how RCA can be applied to different observed phenomena in EDM NVH behavior and detected deviations between the initial model and the measurements, the main influencing parameters, and the identified improvement potential for simulation models.
Custom electrohydraulic solutions can address unique demands not satisfied by standard components. As mobile equipment is pushed to perform in increasingly demanding and challenging environments - ranging from frozen construction sites to harsh marine applications - some OEMs are discovering that customized solutions can provide significant advantages. Standard electronic controls and hydraulic components are carefully engineered to meet the requirements of a broad range of typical applications. For many OEMs, these components provide a dependable and cost-effective foundation, especially in environments and duties that don't push operational boundaries.
As mission-critical systems demand more processing power, real-time data movement, and multi-domain interoperability, rugged embedded systems are being transformed. Today's military and aerospace applications increasingly demand the merging of AI computing, enhanced sensor interfaces, and cybersecurity - all under harsh environmental conditions. At the heart of this evolution is the 3U OpenVPX form factor, a modular, compact, and ruggedized hardware standard and increasingly the SOSA aligned subset of the architecture. However, next-generation systems need to go further: supporting higher bandwidth, better thermal efficiency, improved security, while maintaining multi-vendor interoperability and long-term sustainability. We'll discuss some of today's enclosure solutions as well as emerging technologies.
This research addresses the issue of noise, vibration, and harshness (NVH) in electric buses, which can hinder their widespread adoption despite their environmental benefits. With the absence of traditional engines, NVH control in electric vehicles focuses on auxiliary components like the air compressor. In this study, the air compressor was identified as a major source of vibration, causing harsh contact between its oil sumps and mounting bracket. Analyzing the vibrations revealed that the sump and bracket were not moving freely, increasing noise. Modifying the bracket design to allow more movement between the components successfully reduced both noise and vibration. The paper details the experimental process, findings, and structural damping methods to mitigate NVH in electric buses.
A good Noise, Vibration, and Harshness (NVH) environment in a vehicle plays an important role in attracting a large customer base in the automotive market. Hence, NVH has been given significant priority while considering automotive design. NVH performance is monitored using simulations early during the design phase and testing in later prototype stages in the automotive industry. Meeting NVH performance targets possesses a greater risk related to design modifications in addition to the cost and time associated with the development process. Hence, a more enhanced and matured design process involves Design Point Analysis (DPA), which is essentially a decision-making process in which analytical tools derived from basic sciences, mathematics, statistics, and engineering fundamentals are used to develop a product model that better fulfills the predefined requirement. This paper shows the systematic approach of conducting a Design Point Analysis-level NVH study to evaluate the acoustic performance of vehicle door systems in terms of transmission loss. This is a very important and useful effort by the design team to avoid the risk of later design changes in automotive door systems for better NVH performance. Statistical energy analysis is used for setup and prediction of transmission loss across a wide frequency range up to 10000 Hz. Various design parameters for vehicle door systems are studied to evaluate their impact on transmission loss and vehicle NVH performance.
The author’s life work in acoustics and sound quality, continuous over more than 40 years, has followed a number of branches all involving measurement technologies and their evolution. The illustrated discussion begins 60 years ago in 1965 at Arizona State University in its Frank Lloyd Wright-designed Gammage Auditorium, and moves to the Research and Development Division of Kimball International, Inc. (Jasper, Indiana) in 1976 with piano research using a Federal Scientific Ubiquitous analog real-time FFT analyzer and Chladni-plate-mode studies with fine sand and high-speed photography of sound board modes. It continues at Jaffe Acoustics, Inc., a concert-hall-specializing consultancy in Norwalk, CT, with early-reflection plotting using a parabolic microphone on an altazimuth angular-readout mounting and either photographing oscillograms, or running a high-speed paper chart printer, assembling “wheel plots” incremented every 10 degrees in azimuth and altitude to map reflection patterns. Involvement with binaural technique began for me in 1986 and led me into the automotive industry, whose SQ evolution and that of HEAD acoustics will be outlined along with an earlier side-branch courtesy of James Shedlowsky (GM retired): a photo-archive of GM pseudo-binaural and binaural techniques and jury evaluations starting in 1952 which has been presented in an earlier Noise and Vibration Conference’s Science Fair.
Road noise caused by road excitation is a critical factor for vehicle NVH (Noise, Vibration, and Harshness) performance. However, assessing the individual contribution of components, particularly bushings, to NVH performance is generally challenging, as automobiles are composed of numerous interconnected parts. This study describes the application of Component Transfer Path Analysis (CTPA) on a full vehicle to provide insights into improving NVH performance. With the aid of Virtual Point Transformation (VPT), blocked forces are determined at the wheel hubs; afterward, a TPA is carried out. As blocked forces at the wheel hub are independent of the vehicle dynamics, these forces can be used in simulations of modified vehicle components. These results allow for the estimation of vehicle road noise. To simulate changes in vehicle components, including wheel/tire and rubber bushings, Frequency-Based Substructuring (FBS) is used to modify the vehicle setup in a simulation model. In this process, analytic springs were added in parallel to the actual rubber mounts, which were also measured using VPT on the actual vehicle. These springs simulate positive or negative changes in stiffness, allowing the study of how changes in the rubber mounts affect the vehicle's NVH performance. In this study, a sensitivity analysis was conducted using the FBS model to observe changes in road noise resulting from variations in bushing stiffness and blocked force. Based on the results of this analysis, the optimal combination of components was proposed for reducing the road noise. This approach provides an efficient and accurate method for analyzing the effects of rubber mount modifications on NVH performance.
Unmanned Underwater Vehicles (UUVs) are used around the world to conduct difficult environmental, remote, oceanic, defense and rescue missions in often unpredictable and harsh conditions. A new study led by Flinders University and French researchers has now used a novel bio-inspired computing artificial intelligence solution to improve the potential of UUVs and other adaptive control systems to operate more reliability in rough seas and other unpredictable conditions.
Over the past twenty years, the automotive sector has increasingly prioritized lightweight and eco-friendly products. Specifically, in the realm of tyres, achieving reduced weight and lower rolling resistance is crucial for improving fuel efficiency. However, these goals introduce significant challenges in managing Noise, Vibration, and Harshness (NVH), particularly regarding mid-frequency noise inside the vehicle. This study focuses on analyzing the interior noise of a passenger car within the 250 to 500 Hz frequency range. It examines how tyre tread stiffness and carcass stiffness affect this noise through structural borne noise test on a rough road drum and modal analysis, employing both experimental and computational approaches. Findings reveal that mid-frequency interior noise is significantly affected by factors such as the tension in the cap ply, the stiffness of the belt, and the properties of the tyre sidewall.
From a Noise Vibration Harshness (NVH) perspective, electric vehicles represent a great opportunity since the noise of the combustion engine, dominant in many driving conditions, is no longer present. On the other hand, drivers accustomed to driving cars with a strong personality (for example typically sporty ones) may perceive "silence" as a lack of character. Our internal study, conducted with a jury of people, has in fact already shown that for half of customers silence should characterize (Battery Electric Vehicle - BEV) vehicle; but, at the same time, the other half of the jury expects feedback from the vehicle while driving. The silence inside the passenger compartment, from an NVH point of view, can therefore be compared to a blank sheet of paper, on which, if desired, sounds designed to satisfy the driving pleasure expected by the customer can be introduced. Starting from this scenario, the paper describes: the approach adopted to define how many and what are the levers to design a good sound for our customers driving a sporty vehicle the engineering guidelines to achieve the desired sound The process followed is a structured flow based on: several focus groups, with experts from different company departments, to define the main dimensions of the sound that can characterize a BEV sporty vehicle for our customers subjective evaluations, expressed according to aspects coming from the focus groups, based on acoustic traces recorded on different BEV vehicles with sound enhancement analysis of objective data and comparison with the main results of the analysis of subjective data As a conclusion and main result, engineering guidelines and directions will be presented to create a good sound for a BEV sport vehicle.
Deutronic is not alone in developing and integrating thermal-management solutions to meet the specific demands of off-highway EVs. Modine, for example, in 2023 launched a new edition of its EVantage battery thermal-management system with a liquid-cooled condenser (L-CON BTMS) that combines proprietary heat-exchanger technology with smart controls and electronics. The system is designed to withstand harsh environments found in mining, construction, agriculture, specialty and transportation applications, according to Mike Kis, Director of Advanced Thermal Systems at Modine.
University of Wisconsin–Madison engineers have used a spray coating technology to produce a new workhorse material that can withstand the harsh conditions inside a fusion reactor.
One of the five major performances of vehicles, NVH(Noise, Vibration, Harshness), has recently emerged in electric vehicles, again. And, front loading NVH simulation is essential to respond nimbly to automotive industry these days. However, the two components of the simulation, mathematical sound absorption modeling equation, and the acoustic parameters, the input factor, is requiring improvement because of lack of robustness. In this study, we tried to strengthen, standardize, and refine the connectivity between micro (fine structure) and macro (acoustic parameter-related physical properties) characteristics, and improve the consistency with actual NVH performance. As a porous polymer material, polyurethane foam, which is widely used for the interior and exterior of automobiles, is treated as a target material. It is expected that further refining of the correlation between three-dimensional microstructure properties of foam such as pore, throat, strut, window, etc. and acoustic parameters such as air flow resistivity and porosity, etc., can result in more precise sound absorption performance in the modeling formula.
Customer preference towards quieter vehicles is ever-increasing. Exhaust tailpipe noise is one of the major contributors to in-cab noise and pass-by-noise of the vehicle. This research proposes a silencer with an integrated acoustic valve to reduce exhaust tailpipe noise. Incident exhaust wave coming from the engine strikes the acoustic valve and generates reflected waves. Incident waves and reflected waves cancel out each other which results in energy loss of the exhaust gas. This loss of energy results in reduced noise at the exhaust tailpipe end. To evaluate the effectiveness of the proposed silencer on the vehicle, NVH (Noise, vibration, and harshness) performance of the proposed silencer was compared with the existing silencer which is without an acoustic valve. A CNG (Compressed natural gas) Bus powered by a six-in-line cylinder engine was chosen for the NVH testing. After NVH evaluation, it was found that when using the proposed silencer, overall exhaust tailpipe orifice noise is reducing by 4-5 dB throughout the engine rpm range. In-cab noise at DEL (Driver ear level) is reducing by 2 dB throughout the engine rpm range except for 1200-1400 rpm range. Pass-by noise is reducing by 1 dB when vehicle is running in 3rd gear and it is reducing by 3 dB when vehicle is running in 4th gear.
Since the standardization of Ethernet in the 1980s, progressive performance advances and economies of scale have made this the leading digital networking technology for commercial, consumer, and industrial applications. Although Ethernet in the factory has now been widely adopted, it lagged behind commercial implementations due to difficulties installing the media in harsh industrial environments, and in the early years, a lack of determinism required for critical applications.
More than half a century has passed since the birth of quantum signal detection theory, which is the cornerstone of modern quantum communication theory. Quantum stream cipher, the quantum-noise-based direct encryption scheme for optical communications at the center of our research, is based on the foundations of quantum communication theory. For quantum cryptography to progress from a theoretical possibility to a more realistic technology, experimental and theoretical research must be complementary.
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