Characterization and Validation of Shock Absorbing Hyperelastic Material Using Analytical and Experimental Methods

Abstract

A wide variety of hyperelastic rubber-like materials, exhibiting strong nonlinear stress–strain relations under large deformations, is applied in various industrial mechanical systems and engineering applications, involving shock and vibration absorbers. An optimal design procedure, of an elevator chassis crashing on a hyperelastic shock absorber in a fail scenario is presented in this work. A series of full-scale experimental trials were carried out, representing the crash scenario of the elevator chassis on the buffer absorber system, after a controlled free fall. A limited number of sensors, i.e., triaxial accelerometers and strain gauges, were placed at characteristic points of the real structure of the elevator chassis recording experimental data. A discrete Finite Element (FE) model of the experimentally tested arrangement involving the elevator chassis and buffer absorber system along with all boundary conditions was developed, used in explicit nonlinear analysis of the crash scenario. Steel material properties and a Mooney–Rivlin material model were assigned to the elevator chassis and buffer, respectively. Applying a fully parallelizable state-of-the-art stochastic model updating methodology, coupled with robust, accurate, and efficient Finite Element Analysis (FEA) software, the hyperelastic behavior of the shock absorber was validated under uniaxial large deformation, in order to tune all material parameters and develop a high-fidelity FE model of the full-scale system. Direct comparison of the numerical and experimental data validated the reliability and accuracy of the methodology applied, whereas results of analysis were used in order to redesign and optimize the elevator chassis, achieving minimum design stresses.KeywordsHyperelastic materialExplicit nonlinear crash analysisModel updating