Simulating cab noise and vibration

Researchers at Kubota and Doshisha University have established a prediction method for the engine-idling state using statistical energy analysis.

There has been a growing awareness of the need to establish measures to reduce noise and vibration levels in all types of vehicles to improve the operator working environment. Although the subject has been researched from every angle, there are no noise and vibration techniques that offer good detection accuracy as well as effective noise and vibration measurement. However, researchers at Kubota Corp. and Doshisha University have had some success in that regard using a method called statistical energy analysis (SEA). The cab they evaluated had a closed, complex shape constructed from components of various materials and shapes.

Existing vibration-simulation methods can be used for structures that are very rigid, such as engines. However, it is impractical to apply those methods to cab structures because each component has complex vibration characteristics in varying frequency bands. The SEA method, on the other hand, considers structural components as a set of equivalent vibrating elements. The components' vibration conditions are evaluated as a macroscopic statistical average-quantity instead of by traditional frequency band and space methods. It assumes that certain vibration modes within some frequency bands are uniformly distributed and are excited to the same degree. Merits of the method are: