Many aspects must be taken into consideration when deciding on a new vehicle, but passenger comfort is a major issue. Beyond needing comfortable seats and leg room, the average car owner needs a car that drives smoothly and quietly, without excess noise and vibration. For manufacturers, the problem of noise, vibration and harshness, or NVH, is a common one that must be dealt with during the production of a vehicle.
Most NVH problems arise after the start of vehicle production. Resolving these issues usually means making structural modifications to the vehicle after expensive tooling machinery has already been implemented. To avoid this inconvenience and cost, changes should be made to the vehicle’s structural design before tooling has been created. This is where simulation comes in.
Software such as Abaqus can simulate the many different sources of noise and vibration that a vehicle may generate or be exposed to. The average driver may not even realize how many different types of noise and vibration can affect a car, because those sources have been eliminated before the car gets manufactured.
Two major categories of vehicle-related noise exist: structure-borne noise, which includes steering column shake, road noise and body boom; and air-borne noise, which includes wind noise, exhaust noise, and engine radiated noise. Treatments for structure-borne noise include isolation mechanisms to reduce transmissibility and the use of damping to dissipate energy, while solutions for air-borne noise include barrier materials to reflect the sound back to the source and absorption materials to dissipate acoustic energy in a porous medium.
A full vehicle NVH workflow involves predicting the interior noise level, identifying the modal and panel contribution, and modifying the structure and passenger compartment to arrive at an acceptable acoustic design. This can all be done in simulation, achieving a quiet vehicle before the vehicle has entered the physical fabrication and testing stage.
Abaqus has workflows that address the numerous types of noise and vibration that can affect a vehicle, including noise not mentioned above such as brake squeal. Tire manufacturers can also benefit from these workflows, as tires are major factors in NVH as well. SIMULIA’s powerful multiphysics capabilities offer engineers and manufacturers invaluable tools for modeling multiple automotive components in order to keep vehicles running as quietly and smoothly as possible, without creating unnecessary tooling.
The recent webinar “Large Scale Linear Simulations” explores vehicle noise and vibration in more detail, and takes a close look at how SIMULIA software can be used to reduce NVH issues in the early design stages. You can access the webinar here.