Our NVH and fatigue expertise covers everything from issues for the smallest components to the dynamics of the entire vehicle – with all noise and vibration sources and transmission paths accounted for.
Vehicle interiors and driver environment
Passengers in vehicles enjoy peace and quiet, but the interior sound and vibration environment is even more important for the drivers. The NVH attributes must ensure good ride quality and adequate driver’s awareness and reaction capability.
ÅF´s Sound & Vibration experts focuses on the reduction of powertrain road, wind noise and vibration. We use advanced equipment and software to define and rank the contributions and transfer paths of structure and airborne noise. Noise or vibration sensitive interior components, such as steering wheels and columns, gear shifts, seats and pedals, electric motors and fans are also optimised. Our wideranging know-how ensures that the best possible solution is found for each problem. The sound quality of control buttons, handles and levers can be optimised for a more expensive feel.
Exterior vehicle noise
There is growing awareness in society of traffic noise, whether it originates from road, rail or air traffic. We can identify and rank the different sources of vehicle noise, create solutions to reduce the noise, and perform pass-by tests to verify the performance of modified designs. Mobile equipment makes it possible to measure exterior noise radiation at our customers’ test facilities.
Powertrain noise and vibration
Old engines and transmissions are major sources of vehicle noise and vibration. Engine suspensions are critical for the interior NVH quality but usually need sophisticated, multi-disciplinary attribute balancing. ÅF identify noise radiation surfaces, rank noise and vibration sources as well as pinpoint sound and vibration transfer paths using measurements and vibro-acoustic simulation. We have special test rigs for rubber mount testing also at high frequencies. We propose and develop modifications and solutions. We also help to develop the sound quality for different types of engines, induction- and exhaust systems in order to match the desired brand image.
In 1959 we carried out our first automotive commission. Since this first assignment for Saab Automobile AB, we have performed complete vehicle modal analysis, idle noise and vibration analysis, root cause analysis, brake squeal and judder, power-steering noise and vibrations, exhaust noise calculations and tuning, tuned damper applications, hybrid modelling and much more.
Chassis and body
Road induced noise or vibrations – transmitted via wheel suspensions and car body – can be reduced or eliminated with sophisticated tuning, increased vibration isolation or structural damping. We have the expertise to identify major dynamic load paths and to design and tune vibration isolation and damping performance with respect to temperature and frequency. In addition to our unique software for the design of damping composites, specialised test rigs and a comprehensive damping material database help us optimise the NVH performance of chassis and body. Brake squeal, creep groan or judder are common NVH problems that cause severe customer annoyance. ÅF has long experience of analysing such brake noise problems, and suggesting solutions based on detailed understanding of the complex dynamics involved. Other typical chassis NVH problems are noise from power steering systems. We have experience from numerous analysis and solution assignments.
Complete vehicle NVH
Employing expertise and experience from a multitude of noise and vibration disciplines is vital when developing the NVH attributes of a new vehicle. The work starts with specifying the complete vehicle noise and vibration targets. Those targets are then used to specify balanced NVH targets for major subsystems and key components. This results in a “NVH budget” for each subsystem and component. Finally, we add all those targets into an aggregate model that enables us to estimate the final noise and vibration level for the finished vehicle. ÅF´s unique combination of simulation tools, large amount of measurement data, and considerable experience in optimising such complex systems provide optimal sound quality and vibration properties for your vehicle. Attractive sound is a key component of a vehicle’s identity. When you close the doors of a premium car, the sound must communicate solidity and reassurance. The interior and exterior sound of any vehicle should enhance its brand image.