A methodology for damping measurement of engineering materials: application to a structure under bending and torsion loading

Abstract

A new method to calculate damping properties of rigid materials to be used in Finite Elements calculations is presented. Its relevance relies in its simplicity regarding the amount of materials data, mathematical treatment and experimental equipment needed. Its application allows more realistic calculation of mechanical parts and structures under dynamic loading. In most of those calculations very unreal assumptions are done when simulating with Finite Elements software to assure stability of the solution. The main reason for that situation is the lack of information of damping properties of materials in databases and the complexity of the reported methodology to calculate or measure them. Another reason is the common development time for new products in industry encouraging engineers to quickly evaluate mechanical performance of the product. Recommendations to select initial parameters are presented. Critical parameters to achieve good mathematical fits of the experimental data are identified. Theoretical treatment, fitting algorithm and experimental procedure are described and proved. Several materials: plastics and ferrous and nonferrous metals are studied to demonstrate the validity of the proposed method. Finally, the method is proved in a complex hyperstatic three-dimensional structure under dynamic loading; including working under resonance conditions. Results obtained prove the validity of the method and its application to real world situations.