In this video, the balance of linear and angular momentum will be considered for deformable, continuum bodies. The rate of change of linear momentum is equal to the sum of body forces and surface tractions. Cauchy’s theorem is discussed. Cauchy stress or true stress is introduced, and we explain how it exists at each point inside the body. This stress is defined for the current configuration.
We show the balance of linear momentum in direct notation and in coordinate notation. Next, the balance of angular momentum is shown and reduced to point-wise form. The condition when the balance of angular momentum will be assured is discussed.