Browse Topic: Harshness
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.
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
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
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
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
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
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
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.
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.
Electrification brings new benchmarks, tools, and challenges to the ongoing battle with noise, vibration and harshness. The complex science of analyzing and abating noise, vibration, and harshness has entered a “new frontier” as the industry transitions to electrified vehicles, experts in the NVH field tell SAE Media. New design and engineering challenges at the component, system, and full-vehicle levels continue to emerge as EV offerings expand beyond the initial wave of predominantly premium-spec products. Engineers note that benchmarking activity and the introduction of new analysis and testing tools related to NVH mitigation are at “crazy” levels. “Our interest in acoustically improved vehicles always is going to accelerate and the NVH technology must always meet customer expectations,” observed Pranab Saha, whose company Kolana & Saha Engineers in Waterford, Mich., specializes in acoustics, noise and vibration analysis and testing. He noted that some of the latest EV designs show
In the current changing noise, vibration, and harshness (NVH) landscape, there is an increased amount of collaboration between NVH engineers and other attribute engineering groups to solve complex issues. One of these complex issues is ride comfort. An increasing amount of ride comfort development is happening between NVH and ride and handling (R&H) engineers. To apply a NVH process to a R&H phenomenon, it is important to ensure that both the transducer selection as well as analysis method will be applicable over the frequency range of interest. Specifically for ride comfort development, the validation of the use of strain gauges and accelerometers along with source path contribution analysis, or transfer path analysis, is key to bridging the gap between NVH and R&H. A source path contribution, also known as a transfer path analysis, model can be utilized to understand the contributions from various sources, both structural and acoustic, to a given set of receivers in the interior of a
The transport refrigeration market is in a transformation like what automotive experienced over the last 20 years using a systems engineering approach complemented with complex attribute optimization to manage product development. With a heavy push for electrification due to government regulations, sustainability initiatives, and designing the products to align with the OEMs electrified platforms Noise, Vibration, and Harshness (NVH) must be considered. Understanding the above along with refined customer expectations the NVH attribute has become even more critical to product quality. This paper showcases the acoustic design of an electrified system using a system engineering approach to achieve unit level targets deploying a system engineering V-model philosophy. Unit level requirements were set and flowed down to component level requirements. A 1D acoustic tool was developed leveraging classic physical acoustics theory and legacy product knowledge to target set what was possible for
With higher customer expectations and advances in vehicular technology, automotive functions and operations are becoming more intelligent. Electric self-priming door locks fulfil the automatic closing and locking of side doors, hatchback doors, sliding doors, liftgates, decklids, etc. They are widely implemented into high-end models for the elegance of soft closing. In the list of perceived vehicle qualities, door-closing sound quality has been one of the important customer concerns in the market. In comparison to conventional door locks, electric self-priming door locks add another dimension to the development of sound quality for noise, vibration, and harshness (NVH) efforts. In this article, the characteristics of door-closing sound involving self-priming door lock mechanisms are analyzed and illustrated. Human perception of different sounds from the self-priming door lock working process is ranked by subjective evaluations. For typical door closing sounds associated with the self
A new auditory sensor will be useful for healthcare devices that diagnose respiratory diseases. The skin-attachable device will also be useful as a sensor in microphones to aid in facilitating communication in disaster situations. It can clearly detect voices even in harsh noisy environments.
What’s the difference between deep space and the deep sea? For a robot, the answer is: not much. Both environments are harsh and demanding, and, more importantly, both are far removed from the machine’s operator.
Transfer path analyses of vehicle bodies are widely considered as an important tool in the noise, vibration and harshness design process, as they enable the identification of the dominating transfer paths in vibration problems. It is highly beneficial to model uncertain parameters in early development stages in order to account for possible variations on the final component design. Therefore, parameter studies are conducted in order to account for the sensitivities of the transfer paths with respect to the varying input parameters of the chassis components. To date, these studies are mainly conducted by performing sampling-based finite element simulations. In the scope of a sensitivity analysis or parameter studies, however, a large amount of large-scale finite element simulations is required, which leads to extremely high computational costs and time expenses. This contribution presents a method to drastically reduce the computational burden of typical sampling-based simulations. For
The critical role of spectrum superiority in the success of battlefield campaigns is evidenced by the enormous investments being made in electronic warfare (EW) capabilities by governments worldwide. Communication technologies, such as 5G, are quickly being adopted by militaries in an attempt to satisfy the demand for exponentially larger amounts of data transmission in a shorter period of time. As quickly as secure communication strategies are being developed to encrypt mission critical data, so too are the technologies used to detect, decode, and disrupt such communications. The security and integrity of critical communications is of the utmost importance as the world progresses towards an increasingly networked theater of operations. The militaries of the world appear to be in widespread agreement that the critical communication infrastructure of tomorrow's battlefields need to be: Rapidly deployable and reconfigurable for mission readiness. Designed for minimal spectral footprint
In aerospace and defense, applications rely on mission-critical components to ensure proper functioning in extreme environments. In the many instances in this field where “mission-critical” means that lives depend on successful operation, harsh conditions present certain development challenges that engineers must be aware of and factor into their designs.
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