Study of Vibroacoustics in Fluid-Coupling System

In recent years, the electric vehicle industry has been booming rapidly to decarbonize the world. One of the major concerns in an electric vehicle is the noise emitted from the electric powertrain system, which affects the driving comfort assistance in electric vehicles. Thus, we have to find the methodology to measure the noise level in an automotive transmission system during the design stage itself. This drives us to develop the methodology on a simple design, having a structural and fluid coupling and then followed by an acoustics analysis. A Transient CFD simulation is performed to generate an excitation source for noise; excitation forces observed in the transient simulation are converted into the frequency domain by performing a fast Fourier transform (FFT). To understand this structural behavior, modal analysis is performed for a simple test model to identify the critical modes. Harmonic excitation sources from CFD fluid coupling are imported to a structural model, replicating the transient phenomenon in the frequency domain. Then harmonic velocity calculated from the dynamic responses is fed into the acoustic system where anechoic chambers are modeled to sensitize the different parameters such as radiation boundary and absorption condition. In this paper, we discussed in detail the acoustics methodology by considering the pressure load from the fluid interactions to excite the structural vibration of the system and studying the different acoustic wave absorption conditions that represent the operating environment. Finally, also presented is how the noise level is changed when we change the different design parameters by using the proposed methodology.