Browse Publications Technical Papers 2009-26-0068
2009-01-21

Analysis of Characteristics of Dampers of Hydrogas Suspension and the Effect of Damping Configuration on the Vibration Dynamics of a Light Tracked Vehicle 2009-26-0068

Damping plays a vital role in design of suspension system for off road, tracked military vehicles. The magnitude of damping provided and the configuration of damping adopted have a significant bearing on the mobility characteristics of tracked vehicle. Two types of dampers have been developed for a hydrostrut suspension intended for a light tracked vehicle. The damper is in built in the hydrogas suspension system. The present paper discusses mainly the experimental determination of damping characteristics, results obtained from vehicle model developed in the software ‘LMS Virtual Lab motion’ with two damping configurations and vibration measurement carried out for validation.
Experimental testing and analysis have been carried out to study the characteristics of two types of dampers. The Hydro gas suspension unit has been gradually compressed to obtain its displacement vs force characteristics. A portion of the graph has been linearised to obtain representative stiffness values of otherwise a nonlinear characteristic suspension for use in obtaining the damping forces. Testing has been carried out at frequencies from 0.5 Hz to 5 Hz at specified amplitudes. Work diagrams, characteristics diagrams have been constructed for different cases and analysed. Damping coefficients in bounce and rebound conditions have been deduced and the average damping coefficient has been calculated.
Experimental measurement of cracking pressures (blow off pressure) have also been carried out for the dampers by gradually increasing the flow rate of the fluid flow till the cracking of damper valves in both bounce and rebound condition.
The effect of damping configuration on vibration characteristics of vehicle has been analysed using Multi
Body Dynamics models developed in ‘LMS Virtual Lab motion’. The model has been analysed with two types of damping configuration (Damping at all bogie-wheel stations and damping at front & rear bogie wheel stations) for semi circular bump inputs. Vibration measurement was also carried out on the vehicle on semicircular bumps to validate the MBD model.

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