Drucker-Prager yield criterion

The Drucker-Prager yield criterion is a mathematical model used in engineering to predict when a material like soil or rock will start to deform or fail under stress. It combines the effects of shear stress (forces that cause sliding) and normal stress (forces that compress or stretch) into a single condition. When the combined stress reaches a certain limit—defined by the material’s properties—it indicates the material will yield or break. This criterion helps engineers design safer structures by understanding how materials behave under different loading conditions, especially in geotechnical and soil mechanics applications.