Von Mises Stress is a theoretical measure used in engineering and materials science to predict yielding of materials under complex loading conditions. It combines the effects of different types of stress—such as tensile, compressive, and shear stress—into a single value, allowing engineers to assess whether a material will deform or fail. The concept is based on the Von Mises yield criterion, which states that yielding occurs when the Von Mises Stress exceeds a certain threshold, known as the yield strength of the material. This helps in designing structures and components that can withstand various forces without failing.