Finite Element Modeling and Analysis of Hydro Gas Suspension System for Temperature Rise Behavior

Hydro gas suspension system is extensively used in armoured fighting vehicle due to excellent ride characteristics, non-linear spring and effective damping characteristics. The suspensions have to withstand high loads and temperatures encountered during a typical vehicle mission. The suspension units are subjected to extensive testing for its performance before fitment into the vehicle. The tests involve measurement of spring characteristics and damping behavior. The damping behavior i.e. energy dissipation as heat is measured by observing the temperature rise pattern in the unit. During the experimental testing it is observed that the temperature rise is very severe in some units and mild in the others. Heat generation in a suspension unit is caused by gas compression, viscous energy dissipation and seal friction. Heat dissipation takes place by various modes of heat transfer. In this paper a Finite Element model of the unit is created to study the thermal behavior of suspension unit. The steady state and transient thermal analysis at various ambient conditions would help to understand the chief mode of heat transfer involved and suggest optimizing the design of the suspension unit. The analysis has indicated that inevitable temperature rise is chiefly due to damping energy dissipation and irreversible polytropic gas compression; and conduction is the chief source of heat dissipation.