Finite Element Model Updating Techniques of Complex Assemblies with Linear and Nonlinear Components

摘要

In this work, finite element model updating techniques are presented for identifying the linear and nonlinear parts of dynamic systems using vibration measurements of their components. The measurements are taken to be either response time histories or frequency response functions of linear and nonlinear components of the system. The model updating techniques were coupled with robust and accurate finite element analysis software in order to produce computational effective results. The developed framework is applied to a geometrically complex and lightweight experimental bicycle frame with nonlinear suspension fork components. The identification of modal characteristics of the frame (linear part) is based on an experimental investigation of its dynamic response. The modal characteristics are then used to update the finite element model. The nonlinear suspension components are identified using the experimentally obtained response spectra for each of the components tested separately. Single and multi-objective structural identification methods with appropriate substructuring methods, are used for estimating the parameters (material properties, shell thickness properties and nonlinear properties) of the finite element model, based on minimizing the deviations between the experimental and analytical dynamic characteristics. Finally, the numerical result of the complete system assembly was compared to experimental results of the equivalent physical structure of the bike.