[Simcenter Solutions] for Powertrain NVH Multi Attribute Balancing


Hi, I’m Ben from Siemens PLM Software. Today, I would like to talk about how powertrain NVH can and should be balanced with other key performance attributes when developing or troubleshooting a car. Car manufacturers are pushing both technological and material limits to reduce their product’s weight and improve efficiency. At the same time, of course, they are posing new complex engineering challenges. To verify solutions they in turn are demanding a careful, often difficult compromise between fuel economy and vehicle performance, such as drivability and NVH. These attributes performances interact with one-another. For example, almost every undertaking to reduce CO2 emissions through powertrain efficiency gains results in the NVH signature being adversely affected. The result being that new countermeasures to control the interior noise and vibrations are required. When dealing with common noise or vibration-related consequences of a downsized powertrain being integrated, traditional NVH methods tend to leave unanswered questions, at least when carried out independently. Transfer Path Analysis, for instance, is limited to one single configuration or variant Operational Deflection Shapes, on the other hand, while instructive for structural dynamic investigations are unfit to evaluate driveline rotational dynamics. Multi-body 3D modeling can cover this, but the number of degrees of freedom expands rapidly, meaning it becomes time-consuming to create and post-process. 1D modeling has obvious limitations in predicting full 3D dynamic behaviour. This leaves the NVH Engineer looking at a series of analysis results, trying to draw conclusions manually. A better, new integrated approach seems of utmost importance. Supported by the Simcenter portfolio, LMS Engineers combine all relevant analysis technologies into one comprehensive solution. In this case creating a digital twin, by using each domains established strengths, such as test based signature analysis, together with 1D and 3D simulation model strengths. With this together, we can diagnose on the full vehicle, and multiple attributes simultaneously. So how do we do it? The process begins with data collected in a multi-physics, multi-metrics testing campaign featuring LMS SCADAS hardware with more than 200 input channels. The resulting data is processed for A, initial diagnosis, and B, to provide input for system simulation models. Such models are easily scaled to meet the exact analysis requirements. Missing parameters for complex systems such as transmission and driveline components can be obtained using advanced reverse engineering methods. The resulting simulations allow the user to evaluate everything from the combustion process through the subsequent torsional signature imposed on the crankshaft, the transmission elements and the driveshaft through to the suspended wheel on the vehicle. In combination with vehicle FRF data the forces calculated at the powertrain mounts, this allows to predict the vehicle vibration and noise, essential when tackling phenomena such as booming noise. When we move into NVH countermeasure definition phase, this can now be done in a fully transparent way, evaluating the impact on fuel consumption and drivability resulting from the NVH countermeasure, in the same system simulation environment. This approach starts to provide a much more interactive method of Engineering communication which encompasses the right physics and attributes while remaining customizable. This process is integrated to match the precise needs of our diverse customers. Thank you for watching, please visit our website for more information.