This paper presents four alternate models of varying complexity to examine mechanical snubbing in elastomeric isolators. Although the modeling, analysis, and experimentation presented is limited to snubbing of elastomeric isolators, the models are generic and can be adapted to other snubbing mechanisms as well, such as friction snubbing. Two of the four models presented in this paper use the Bouc–Wen model in order to capture hysteresis and gradual stiffening behavior, which is generally exhibited by elastomeric snubbing systems. The other two models are relatively simplistic and do not account for a time-varying parameter to model significant hysteresis. However, these two models can still be useful for applications with a small range of excitation frequencies and for applications where the snubbing design needs to incorporate an abrupt transition in stiffness. A parameter identification technique is used to determine the variables associated with each model. The parameter identification technique is based on the use of an optimization algorithm associated with the force–displacement characterization. All four models presented in this paper capture the coupled dynamics of the isolation system and the snubbing system and are, therefore, a significant improvement upon the currently used models. The models presented are expected to facilitate the design and analysis of a passive isolation system in conjunction with the design of the snubbing system and the base frame supporting the snubbing system.
Robust Time-Varying Parameter Identification for Composite Load Modeling
