During the lifetime of a passenger car its shock absorbers should be checked repeatedly in order to avoid accidents in critical situations such as e.g. driving through pot-holes. For routine checks of this kind a drop test method has been developed. In such a test the front or rear wheels of the car are standing on ramps These ramps are suddenly removed to initiate a drop of about 50 mm. As a consequence of the impact on the ground, the wheels and the car body undergo free damped vibrations. The vibration amplitudes as well as the forces acting on the ground are recorded by a microprocessor system. Reference measurements, using different cars with known spring/damper characteristics, were made to develop a suitable mathematical model for the description of the dynamics during the test. It turned out that for every wheel a nonlinear two-degree-of-freedom system is sufficiently accurate to determine the characteristics of the system components, including the nonlinear characteristics of the shock absorber. Thus its residual efficiency as well as the contact force between wheel and ground can be assessed by means of a simple and quick routine test.
Test method for checking the efficiency of passenger car shock absorbers
Eine Testmethode zur Überprüfung der Effektivität von Stoßdämpfern für Personenkraftwagen
IMAC, Proc. of the 9th Int. Modal Analysis, Conf. ; 2 ; 1136-1142
1991
7 Seiten, 10 Bilder, 7 Quellen
Aufsatz (Konferenz)
Englisch
Kraftfahrwesen | 1976
|Engineering Index Backfile | 1940
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