Design of a computer application for experimental modal analysis

The Master Thesis project concerns the creation, validation and optimization of an application, based on the Matlab Graphical User Interface (GUI), used to process data for an experimental modal analysis. A real-life application case on a carbon fibre monocoque is eventually presented. Modal analysis is a tool to understand and describe the dynamic behaviour of a structure, on the basis of its modal parameters: damping, natural frequencies and mode shapes. The work is mainly divided in three parts: the first one is an introduction to vibrating systems, starting from a single degree of freedom and ending with the explanation of a modal parameter extraction technique used for multi-DOF systems, and therefore in the app, called LIPEZ. The second part deals with the app validation, using it on a lumped 7-degree of freedom system whose mass, stiffness and damping matrix are known, as well as its modal parameters. Theoretical mode shapes and those coming from the app are compared by means of the Modal Assurance Criterion (MAC). The last part concerns a real E.M.A. conducted in October 2022 on a carbon fiber monocoque of team H2politO new prototype IDRAzephyrus. In this part are described all the instrumentation used during the experience and the mandatory procedures to follow before the test. Finally it is presented the execution of modal analysis on the recorded data. The aim of this thesis is to simplify the execution of a real modal analysis, whose formulation requires different codes and functions. The app presented allows to summarize everything in a few keyboard inputs, making this investigation more flexible and easy to carry out.