Influence of plastic deformation over the natural frequency of steel structures

The modal analysis is an important step during the project of structures. Throughout it, it is possible to know structural properties that may help when it is necessary to analyze the integrity of the system. Many studies and researches are being developed to understand more deeply the phenoms that involve mechanical vibrations, especially because of their importance. One of these phenoms, for example, crucial in aeroelasticity, is the flutter, that requires the coupling of two different natural frequencies, which may happen when the material is plastically deformed. In its turn, the coupling requires the variation of natural frequencies, which was experimentally observed by this work through traction tests and modal analysis.