Systematic evaluation of vibrational behavior of electric drive trains

The design and engineering of electrical drive trains is a multi disciplinary task. Usually several teams of different technical fields are involved in the development of new drive trains. Each team focuses on their own field of expertise. Even though the interactions of the described teams are well defined, acoustic irregularities are determined not before prototype stage frequently. This leads to the demand of systematic evaluation of the exciting sources and their transfer paths to the radiating surfaces. Once the sound radiating surfaces are identified, the main challenge is the decoupling of the excitation of different components of the drive train, such as electrical machine, gears, bearings etc. This step is crucial for the identification of design steps to improve the acoustic behavior. This paper presents a methodology to estimate structural transfer functions from the stator teeth of an electrical machine to the surface of its housing. The methodology is based on an operational transfer path approach and relies on a set of measurements where the force excitation is delivered by the machine itself. Since these forces are coupled a procedure for the decoupling of the transfer paths is presented. The whole model is in time domain and allow for the consideration of non linear structural behavior.