Model Up Date for the Reconstruction of Dynamic Base Excitation of an Experimental Set-Up Based on Dynamic Measurements.

In my work I will try to mark out possible techniques for the construction of an update dynamic model, for a further computational of reverse exaction applying on a physical real model. This kind of research will be executed in different stages. All the steps required a deep understanding of dynamics with proper application of technical and analytical skills alongside a creative mind. In the first step a physical 3 story scaled framed structure model made with steel and aluminum materials was constructed. Every single element was measured to understand its volume and weight. This kind of information is useful for the computation of the mass matrix and the FEM model. As a second step, we performed an experimental investigation to understand the real motion quantities at the base: modal shapes and natural frequencies. Scientific Instruments and tools such as impulse hammer and accelerometers were also used for that matter. Afterwards the analysis of the statistical measurements were done through numerical soft wares with special considerations about the noise error influence. In the subsequent phase a numerical FEM model was performed by using a commercial software. Validation of mass property was done by preforming static analysis and calculation of the reactions on the base. Afterwards a [2D] framed modal analysis was executed. Iteration procedure was conducted in order to understand the precise stiffness value of the joints, represented by not perfect hinges. As an ultimate step, a literature research on the subject of inverse base excitation computation was done. Suitable methods and formulation were taken into account for the identification of numerical investigation procedure. For this procedure, a suitable measurement concept was developed.