Mechanical vibrations have attracted the attention of engineers and researches long time ago. Vibration problems require a deep understanding of mathematical modeling and signal analysis, but they also require practical experience. Even though there is abundant literature about the subject, there are still many unknown answers from modeling through measurement interpretation. The scope of it is the identification of discontinuities in the stiffness properties of mechanical systems, and how these discontinuities affect its behavior. The authors seek to find, with a practical perspective, those parameters that cause nonlinearities, or modify the stiffness properties.