A Simple Model for the Simulation of Low-Frequency Disc Brake Noise

2007 ◽  
Author(s):  
Ragnar Ledesma ◽  
Shan Shih
2002 ◽  
Vol 13 (01) ◽  
pp. 025-037 ◽  
Author(s):  
Roberto Carle ◽  
Søren Laugesen ◽  
Claus Nielsen

In a clinical experiment, it was found that there is a high correlation between the compliance measured by tympanometry and the minimum size of the earmold vent, which just solves the client's occlusion problem related to his/her own voice when using a hearing aid. For ears with sensorineural hearing losses, compliance explained 59 percent of the variation in vent size, whereas the average low-frequency hearing loss explained as little as 0.3 percent. In a laboratory experiment, the objective occlusion effect measured with the participants' own voices showed a similar relationship with compliance. Whereas the former relationship between compliance and vent size may be explained by a simple model, the latter relationship turns out to be the opposite of what a firstorder model predicts. Hence, compliance must be indicative of another aspect of the occlusion mechanism, which has a more profound influence on the observed occlusion effect than compliance itself.


2001 ◽  
Author(s):  
Yoichi Kumemura ◽  
Yoshikazu Gamo ◽  
Kimiyasu Kono ◽  
Satoru Suga
Keyword(s):  

1999 ◽  
Author(s):  
H. Ouyang ◽  
J. E. Mottershead ◽  
D. J. Brookfield ◽  
S. James ◽  
M. P. Cartmell ◽  
...  
Keyword(s):  

Author(s):  
Hartmut Hetzler ◽  
Wolfgang Seemann

Today, low frequency disc-brake noises are commonly explained as self-sustained stick-slip oscillations. Although, at a first glance this explanation seems reasonable, there are indices that cast doubt on it. For instance, the basic frequency of the observed oscillations does not scale with the disc-speed as it is with stick-slip oscillations and the classical model does not explain the observed ending of the vibrations beyond a certain speed. Indeed, our experimental studies on groaning noises reveal two different vibration patterns: stick-slip vibrations at almost vanishing relative speed and a second, differing vibration pattern at low to moderate relative speeds. Yet, these two patterns produce a very similar acoustic impression. While the experiment provides a vast amount of data, the dimension and structure of the underlying oscillation is not known a priori – hence, constructing phenomenological minimal models usually must rely on assumptions, e.g. about the number of DOF, etc. Due to noise and complexity, the measured raw data did only allow for a first straight forward insight, rendering further analysis necessary. Hence, time-delay embedding methods together with a principle component analysis were used to reconstruct a pseudo-phase space together with the embedded attractor to analyse for the system's dimension and to separate signal from noise.


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