Model of thermomechanical behavior of a shock-absorbing unit

Abstract

Modern industries use structures that should meet strict requirements for dynamic characteristics specified in many branches, such as aviation, military, instrument–making, automotive, etc. The fulfillment of these requirements is associated, in particular, with the use of the damping systems of structures, the operation of which is determined by a complex of nonlinear processes (contact interaction, dry friction, large deformations, etc.), thus making the task of constructing their mathematical models relevant. The currently used approaches to modeling these systems do not fully take into account the nonlinear effects intrinsic to the above processes, or require significant computational resources, and may also require a large number of experiments. The purpose of this study is to construct and identify a model of deformation of a shock absorber, taking into account friction, temperature, viscoelastic and hyperelastic behavior of the material and to determine the following integral thermomechanical characteristics of a shock absorber under various loading conditions: a shock absorber response to displacement, the amount of heat released during one deformation cycle, the magnitude of the friction force. At the first stage, a model of visco-hyperelastic behavior of a material is constructed and its parameters are calculated based on the real experiment data. The hyperelastic characteristics were determined using the results of free tension-compression and constrained compression tests, and the parameters of the viscoelastic model were found in the harmonic load and variable temperature experiments. Then, a finite element model of the damper is constructed using the ANSYS software package and the parameters of friction due to contact interaction are determined by making comparison with the results of deformation tests of the shock absorber under the conditions of axial and transverse loading. At the last stage, the constructed model is used to evaluate the thermomechanical behavior of the shock absorber under cyclic deformation, which is also realized during vibration. As a result, the dependencies of viscous and dry friction energy released during one deformation cycle on the friction coefficient, velocity and temperature are obtained.