Multi-degree-of-freedom modeling of mechanical snubbing systems

摘要

This paper presents a multi-degree-of-freedom model for the design and analysis ofmechanical snubbing in elastomeric isolators. The model consists of a three degree-of-freedomrigid body that is assembled to a rigid frame by means of elastomeric isolators and a snubbingsystem. The isolators are supplemented by the snubbing system so as to limit the displacementof the rigid body in all three directions of motion when the system undergoes transient loadingor overloading conditions. The model is piecewise non-linear and uses normalized Bouc-Wenelements in order to capture inherent hysteresis of the elastomeric isolators and the snubbingsystem as well as the transition in stiffness and damping properties resulting due to inherentcoupling between the isolators and the snubbing system. Separate elements are used to modelthe enhanced stiffness resulting from the snubbing system in the translating directions ofmotion. A set of elastomeric isolators and snubbing systems is used for data collection,characterization and model validation. The data collection is carried out at multiple strainamplitudes and strain rates. A conventional least squares based parameter identificationtechnique is used for characterization. The completely characterized model is then used forsimulating the response of the rigid body and the simulation results are compared toexperimental data. The simulation results are found to be in general agreement with theexperimental data.