Rigid Structures: Analysis and Definitions

This lecture focuses on the analysis of rigid structures, beginning with a review of previous concepts related to systems of forces and equilibrium. The instructor defines what constitutes a structure and distinguishes between rigid and non-rigid structures, emphasizing the internal degrees of freedom present in non-rigid structures. The lecture introduces the concept of trusses, detailing the characteristics of ideal trusses and their assumptions, such as members being connected through smooth pins and external forces applied exclusively at the joints. The instructor illustrates these concepts with examples, including a revisited ladder problem, to demonstrate how to compute internal forces and moments within structures. The analysis involves drawing free body diagrams and applying equilibrium conditions to determine reaction forces. The lecture concludes with a discussion on the importance of understanding internal interactions between members in a structure, setting the stage for more detailed analysis in future classes.