Abstract
KEYWORDS:
shock absorber, self-adjustable absorber, motorcar, simulation, FEM.
ABSTRACT:
The authors developed a study for a self-adjustable shock absorber, in order to adjusting the damping chart according to road characteristics, using MSC/Nastran software and so to establish the advantages of self-adjustable shock-absorber relative to standard one.
The self-adjustable shock absorber has the advantage of providing a large range of damping coefficients, function of the relative piston position in the cylinder, as well as a technological simplicity.[1] Both on rebound and compression, the damping coefficients have low values at the beginning of the strokes becoming medium at the middle of the strokes and high and very high to its end. Thus, a better adherence heel-road, comfort and protection at the end of the stroke are assured, comparative to standard shock absorbers. With other advantages like: decreasing of lift/squat at acceleration, decreasing of dive/lift at braking, decreasing of pick/roll, the automotive self-adjustable shock absorber confers high performances (nearly semi-active suspensions) at low costs (nearly standard shock absorbers).
In order to determine the advantages of progressive-damping characteristic that can be physically realizable by this type of shock absorber, theoretical research has been conducted. Damping characteristics for different load static position were established, based on the variation of hydraulic characteristics function by stroke, which means the variation of damping coefficient relative to vehicle load.
The paper presents a comparative study between a motorcar fitted on with a standard shock absorber and a motorcar equipped with the new developed shock absorber, using a 6-freedom degree-car model [2]. The road-induced vibration was determined using FEM. The comparative results show that the automotive self-adjustable shock absorber named and progressive shock absorber can provide a perceptible comfort improvement, relative to standard ones.