Paul Sas

Learn More
The finite element method (FEM) is widely accepted for the steady-state dynamic response analysis of acoustic systems. It exhibits almost no restrictions with respect to the geometrical features of these systems. However, its application is practically limited to the low-frequency range. An alternative method is the wave based method, which is an indirect(More)
The wave based method (WBM) is considered for the steady-state dynamic analysis of acoustic problems as an alternative for the finite element method (FEM). The WBM exhibits better convergence properties with respect to model sizes, but the computation (CPU) times obtained by the current MATLAB implementation are large compared to commercially available FEM(More)
This paper describes a feasibility study on dither control for automotive wiper squeal. Wiper squeal is a tonal noise caused by an unstable vibration due to the friction between wiper blade and windscreen. Dither control is the superposition of a high-frequency signal, in this case a high-frequency vibration, to stabilize a low-frequency unstability in a(More)
This paper discusses the development of an advanced Iterative Learning Control (ILC) scheme for the filling of wet clutches. In the presented scheme, the appropriate actuator signal for a new clutch engagement is learned automatically based on the quality of previous engagements, such that time-consuming and cumbersome calibrations can be avoided. First, an(More)
In many acoustic simulations, particularly when using lumped parameter models or electrical analog circuits , the acoustic impedance of a component needs to be determined accurately. A widely used acoustic impedance measurement method is the " two microphone transfer function method " , which is standardized in ISO-10534-2. When the acoustic impedance is(More)
In this investigation, the acoustical impedance of an internal combustion engine is measured and simulated. The measurements are based on the two microphone transfer function method, which is described in the standard ISO/FDIS 10543-2. The method uses the transfer function between two microphones positioned on a waveguide connected to the impedance to be(More)
Wet friction clutches play a critical role in a transmission system. The clutches progressively degrade while the transmission is under operational condition. If the clutches unexpectedly fail, then the complete transmission will fail. To avoid unexpected failures, a proper condition monitoring tool extended with a lifetime prediction method must be(More)
This work covers the design of active structural acoustic source controllers, where the aim is to reduce radiated noise by placing actuators as close as possible to the disturbance source, in order to intervene as early as possible in the transfer path between disturbance and noise radiators. The considered application is rotating machinery, where the noise(More)