The aim of the course is to introduce the students to the nonlinear behaviour of materials and structures, with particular emphasis to material and geometric nonlinearities. At the end of the course, the student will acquire the ability to understand the mechanical behavior of the nonlinear behavior of beam structures. The student will also acquire the methodologies for calculating the load bearing capacity of a structure, related to the attainment of the material resistance (plastic collapse) or the loss of structure stiffness (buckling collapse).