Optimization of Damping Characteristics for Two Wheelers

In developing countries roads have a mix of high undulations as well as smooth and flat surfaces on highways. And also two wheelers are used for commuting with one or two people rather than for sport. A variety of spring characteristics are required to maintain the ride height for solo and doubles and wide variety of damping characteristics are required for various road conditions, loading conditions and speeds to achieve desired ride and handling characteristics. The spring and damper characteristics that are desired for good ride comfort will results in poor handling at high speeds. Achieving a very good level of ride comfort on rough and smooth terrains combined with an equally good level of handling with various loading conditions in the speed range of 20 to 120 Kmph is a highly challenging task. So most of the two wheelers are tuned for one loading case (solo or doubles) and either for ride comfort or handling with compromise on the other.

In this paper, a methodology to find shock absorber characteristics required for various road undulations and loading conditions of two-wheeler is presented. A multi body dynamic model is developed with 13 DOF to study the behaviour of rear damper for various road inputs. Advanced modeling techniques are used to model the seat and front fork friction behaviour. The model is simulated with actual road input and validated with experimental measurements. Simulations are carried out on different size and shape of road undulations like pothole, hump, step up and step down with solo and doubles at various vehicle speeds. Damper characteristics are optimized to achieve minimum sprung mass acceleration for two payload conditions, solo and doubles at various speeds.