Noise-vibration-harshness

Hybrid GMT/steel used for instrument panel carrier on vehicles from Ford, Volvo and Mazda, reduces weight, provides easier assembly, lowers cost and improves noise/vibration/harshness (NVH) and crash performance. 

However, besides exhaust emission control - Fig. 2 - various other aspects in engine development have to be taken into account. The most challenging parameters for the diesel engine are noise, vibration harshness (NVH) control and the necessary technology versus cost required for competitive performance. 

Last but not least, the customers are expecting from a fuel ceU vehicle performance on the same level as conventional ones. System power, dynamics, power to weight ratio as well as maximum speed are key elements for the performance feeling. The subjective comfort of the passengers and the environment is influenced by the not to be underestimated effect of the noise-vibration-harshness performance. 

Most butyl rubber is used in the tire industry. Isobutylene-based rubbers are used in underhood hose for the polymer s low permeability and temperature resistance, and high damping, resilient butyl rubbers are used for NVH (noise, vibration, harshness) applications such as automotive moinits for engine and vehicle/road NVH attenuation. ... 

Typical use cases for FDMU always arise when several different physical effects appear on the tight space of a product. One such example is the passenger car, wherein the comfort of a living room is anticipated, which is affected by many vehicle-related as well as environmental influences. A central component of comfort optimization is the vehicle acoustics, which is considered in the complex NVH (noise, vibrations, harshness). While noise and vibration can be determined by appropriate experimental methods, harshness is a subjective property, and reflects human subjective impressions [27]. The psychoacoustic characteristics of a vehicle are a decisive factor for almost every buyer of premium cars. 

Customer Initial cost Operational and maintenance costs Quality Range (between refueling) and refueling convenience Passenger/cargo space Performance (acceleration, speed, ride quality, acceptably low levels of noise, vibration, and harshness) Safety... 

Another important performance imperative is NVH (noise, vibration, and harshness) concerns. FEA can help in this aspect as well by making predictions about natural frequencies. In our example, the frequency predicted for the first mode is... 

NVH noise, vibration, and harshness — the acoustic and tactile stimuli... 

Polypropylene, a homopolymer polyolefin engineering plastic provides excellent chemical resistance, purity and it is the lightest of all commercial plastics. PP offers innovative solutions to many challenges that face the automotive industry today. Its low density compared to traditional materials significantly contributes to fuel economy and reduced material costs. Its excellent noise, vibration, and harshness (NVH) properties contribute to enhanced passenger comfort. Thus, PP has become the most important thermoplastic material in automobile industry. PP homopolymers, random copolymers, and impact copolymers are used in products such as automotive parts and battery cases, carpeting, electrical insulation, and fabrics. 

BSR/NVH BSR means "buzz, squeak, and rattle." NVH stands for noise, vibration, and harshness. This step examines the interaction of the component with others in the system. 

Elastomers serve a large potion of the overall need for plastics in the automotive industry. Their prime applications are in energy absorption, followed by noise, vibration, and harshness. However, the industry is crowded with many equivalent choices, and competition is growing fiercely. Sometimes, as a result of regulatory changes in areas such as safety and fuels, the need arises for either more elastomers or novel ones with differentiated properties. 

The low specific density provides weight saving and helps to improve fuel economy, while also reducing cost. The intrinsically superior noise, vibration and harshness (NVH) properties contribute to improved comfort. 

Most automotive R D projects within adaptronics are concerned with active vibration control (AVC) and active structural acoustic control (ASAC) for optimization of NVH (noise, vibration and harshness) characteristics and even soimd design. Furthermore, active measmes to increase the passive safety of vehicles are being developed. Shape and position control as well as structmal health monitoring (SHM) are stiU of secondary importance. 

In recent years, demands have increased in using polyamide (PA) and polyethyleneterephthalate (PET) products to replace certain metal structures in the automotive vehicle air induction and power train systems, lawn/garden and power tools [1-2]. An average car uses 18 kg of PA and 3 kg of PET. With the annual vehicle production at nearly 12 million, the needed amount of PA is more than 200 million kg and more than 45 million kg for under-the-hood applications alone [5]. The design of these components, especially those critically stressed parts such as vibration welded air intake manifolds [5-4], door and instrument panels, requires advanced analyses of structure [5-5], NVH (noise, vibration, and harshness), welded joints [5], and service life [7],... 

Conformal coatings protect electronic circuitry from moisture, dust, chemicals, solvents, and other harsh environments. Although usually only a few mils thick, they also dampen the effects of mechanical and thermal stresses, vibrations, and electrical noise. Conformal coatings also have been used to provide electrical insulation by inhibiting dendrite growth, a potential cause of short circuits. 

Sound is transmitted through the air by sound waves which are produced by vibrating objects. The vibrations cause a pressure wave which can be detected by a receiver, such as a microphone or the human ear. The ear may detect vibrations which vary from 20 to 20 000 (typically 50-16 000) cycles each second (or hertz (Hz)). Sound travels through air at a finite speed (342 m/s at 20°C and sea level). The existence of this speed is shown by the time lag between lightning and thunder during a thunderstorm. Noise normally describes loud, sudden, harsh or irritating sounds. 

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