Lecture
This lecture covers the representation of the stress state of an object in 3D, focusing on the stress tensor and its properties. The instructor explains how to interpret the different elements of the stress tensor and the sign convention for normal and shear stresses. The stress tensor is symmetric, and both stress and strain tensors are 2nd order tensors that can be diagonalized to give the principal values of stress and strain. By passing three mutually orthogonal planes through a point and analyzing stress vectors, the stress state can be fully characterized with only 6 stress values, representing the intensity of internal forces within a body.