Browse Topic: Harshness
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
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
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
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
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
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
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
Several conventional methods on preparation of exfoliated graphite are in practice. However, their major limitations are poor quality of exfoliated graphite, lower yield, more expensive with higher processing time. To address these issues, a unique method for development of exfoliation of graphite using tri-solvents namely Water, Ethanol and Acetic acid is attempted in the present work. Ethanol acts as a supporting group for the long term stable dispersions of ex-graphite nanosheets. Glacial acetic acid, which readily dissolves in water, penetrates through the layers of graphite sheets and breaks the -C=C bond force between layers with the help of stirring and sonication resulting in exfoliation of graphite layers. Exfoliated graphite nanosheets were produced by using optimized mixtures of water, acetic acid and ethanol. XRD, SEM and FTIR studies have been carried out on the developed exfoliated graphite. Nanosheets of exfoliated graphite with size ranging from 100 nm to 150 nm were
Avionics systems provide electronic guidance, navigation, and communications through harsh and hostile environments for a wide range of airframes. Operating environments present elevated levels of shock and vibration; vacuum-like conditions of high altitudes; corrosive effects of hydraulic fluids, fuels, and other chemicals; and the effects of wide temperature ranges. Avionics systems must handle such challenging environments even as they are being designed with greater functionality into smaller payload spaces
Diamond anvil cells have made it possible for scientists to recreate extreme phenomena, such as the crushing pressures deep inside the Earth’s mantle, or to enable chemical reactions that can only be triggered by intense pressure, all within the confines of a laboratory apparatus. To develop new, high-performance materials, scientists need to understand how useful properties, such as magnetism and strength, change under such harsh conditions. But often, measuring these properties with enough sensitivity requires a sensor that can withstand the crushing forces inside a diamond anvil cell. By turning natural atomic flaws inside the diamond anvils into tiny quantum sensors, scientists have developed a tool that opens the door to a wide range of experiments inaccessible to conventional sensors
In the following, a multiphysics simulation approach for the calculation of the noise, vibration, and harshness (NVH) behavior of a three-phase permanent magnet synchronous machine is presented. Based on a defined operating point, the electromagnetic force densities in the air gap between the rotor and stator are determined on the basis of the flowing currents using the finite element method (FEM). In addition to the electromagnetic force densities, the structural modes with natural frequency and natural mode shapes are also determined by modal analysis. The electromagnetic forces and structural modes can then be reduced to the most important contributions in the modal space to significantly reduce the computation time. Using a frequency-dependent damping model, a full motor run-up is simulated and the resulting velocities at the surface of the machine are evaluated. The simulation results are then compared with a measurement and validated. The extent to which this modeling approach is
Aerospace and defense technology must operate reliably in a wide variety of extreme conditions, including very high and very low temperatures and amid saltwater and harsh chemicals (from deicing fluids to missile fuel). Further, manufacturers must meet stringent requirements. As a result, the testing regimen involved in ensuring battlefield readiness is complex and multifaceted – not only for the devices that end up in soldiers’ hands, but also for the many component parts that make those devices work
Eddy current displacement sensors belong to the inductive displacement group of sensors and are well-adapted for industrial applications. Unlike conventional inductive sensors, the measuring principle for eddy current sensors enables measurements on non-ferromagnetic materials (e.g., aluminum) as well as ferromagnetic materials (e.g., steel). They are designed for non-contact and wear-free measurements of displacement, distance, position, oscillation, vibration, and thickness. Therefore, they are ideally suited to monitoring machines and systems — they can make measurements in harsh Industrial environments, even where pressure, dirt, or temperature fluctuations occur
In the aerospace industry, components are subjected to harsh operating environments. Extremes of temperature, corrosive particulate matter in the air, friction and a variety of operating factors combine to increase the risk of wear and tear, corrosion, and damage
The automotive industry is rapidly changing as electric vehicles (EVs) have gained share in the market, bringing new challenges to ensure passenger comfort through noise, vibration, and harshness (NVH) management. Automotive acoustics engineers employ a variety of materials to reduce NVH across the audible frequency spectrum. In general, these materials have been tailored to address vibrations related to internal combustion engines (ICE). For example, liquid applied sound damping (LASD) coatings are widely employed to reduce structural vibrations due to their ease of application and light weight. LASD coatings are typically applied to the vehicle body to reduce structural vibrations at frequencies <1000 Hz, since ICE vehicles tend to exhibit vibrational modes primarily at these frequencies. However, EVs are known to also excite higher frequency vibrational modes up to 3000 Hz. Additionally, the lack of masking noise from the engine may lead these noises to be more noticeable to the
The automotive air-conditioning (AC) components fitted on passenger car having high vibration make significant impact on vehicle noise and harshness inside the cabin. Hence, it is necessary to reduce the vibrations within the permissible limit. This can be done by improving dynamic behavior of the assembly under vehicle fitments. The present paper explains about design improvement carried out on the condenser assembly to increase strength of the mounting brackets as well as to reduce the noise level by reducing the vibrations. Modal frequency response analysis has been performed on the existing condenser and found that there was relatively high vibration on the assembly due to low stiffness of the bracket. From the acoustic analysis, it was observed that the noise is occurring due to high vibration at resonance condition. By doing the design changes on the assembly, modal frequency increased relatively. Accordingly, noise level also reduced. The Vibro-acoustic analysis predicted the
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