Mathematically expressed von mises stress formula is used to find the yield strength of any ductile material. You can refer the below von mises stress equation to find σv. Just, multiply normal stresses (σx) and (σy). Then square the shear stress (txy) and multiply it with 3. Now add the two derived values along with the square of normal stress (σy). Subtract the resultant value from (σx). The square root of the resultant value is the von mises stress of a material.
You can use the above mentioned Von mises stress formula to find σv induced in the material which exceed the yield strength of the material. It helps to know whether the design can withstand the load.