This presentation was made at the NAFEMS Eastern European Seminar "Engineering Analysis & Simulation in the Automotive Industry" held on the 7th of November in Bucharest.

Automotive manufacturers and suppliers are constantly challenged with delivering innovative, safe, and dependable vehicles to market as efficiently as possible. As a result, engineering teams must discover, evaluate, and successfully implement leading-edge technology and methods to produce a reliable, effective outcome. Many of these efforts now come together under concepts such as Industry 4.0, Digital Twin, CAE Democratization, and Cloud Solutions. But what do these really mean for you, as a simulation specialist?

Resource Abstract

The recent automotive electrification trend leads to the need for developing highly optimized electric driving units both from a durability stand point and also from a noise and vibration stand point.



This paper presents a method for optimizing the radiated sound of the electric driving unit under operating conditions. As the title suggests, the method is basically an Analysis – Evaluation (Subjective listening + noise level assessment) - Structure Optimization loop.



The drive unit is loaded with the steady state harmonic loads which arise during operation at constant rotational speed. Only the magnetic loads are considered. These will be calculated via electromagnetic transient analysis of the electric motor.



Further, the method employs the FE modeling of the drive unit structure. Next the steady state harmonic response is calculated using the mode superposition method. The mode superposition method is suitable in this situation not only because it allows for a faster solutioning but also because it helps when diagnosing noise issues caused by resonant structural response. The calculation of the natural frequencies is necessary in order to understand which modes are being excited. Based on the structural response, a subsequent acoustic response is then computed. The sound pressure level is then assessed. In addition to this, the actual sound radiated by the unit is being played for some subjective assessment. The peak responses are analyzed in order to understand what the root cause is. Some structure optimization is then applied based on the strain energy assessment of the mode shapes which are being excited.



The optimized structure is being re-analyzed to assess if the desired performance is met.