Relative Deformation in 3D: Strain Matrix

This lecture covers the concept of relative deformation in 3D, focusing on the strain matrix and its relation to displacement. It explains how tensile or compressive forces create deformation, the intensity of deformation, and the displacement gradient. The instructor discusses the theory of infinitesimal relative deformation and the use of the relative strain tensor. The lecture also delves into the application of the generalized Hooke's law, flexibility matrix, and stress-strain relations. Examples illustrate the calculation of relative strains, stress states, and volume changes in 3D structures. Emphasis is placed on understanding constraints in the plane, relative stresses, and strains, as well as the equilibrium equations for 3D systems.