Lecture
This lecture discusses the concepts of stiffness and strength in structural mechanics, focusing on how structures deform under load and their ability to withstand loads without failing. It covers strain, gauge length, tensile and compressive forces, as well as examples of strain calculations. The lecture also explores macroscopic and microscopic strain definitions, governing equations, and the relationship between strain and deformation. Additionally, it delves into shear strain, stress, and the measurement of strain using strain gauges. Examples of stress analysis in wires and trusses are provided, emphasizing the importance of understanding the internal response of structures to external loads.