## General Mechanical

#### Could any one explain me, what is the diff between maximum principal stress and normal stress ?

• HarsihilZLHZ
Subscriber
In ansys, it shows max principal stress(sigma_11) and normal stress , aren't they both same?n
• Kai
Ansys Employee
Hi, principal stress and normal stress are different. They are only the same in certain conditions such as simple tension. You may google principal stress to find out more details on how principal stress is calculated.n
• HarsihilZLHZ
Subscriber
In cauchy stress tensor, sigma_11,sigma_22,sigma_33 are the principal stress and sigma_12,sigma_13,sigma_21,sigma_23,sigma_31,sigma_32 are the shear stress is correct ?nI am confused between Principal stress and Normal stress (shows in Workbench)nAny link or formulation can anyone share?.
• Kai
Ansys Employee
sigma11, sigma22, sigma33 are normal stress, they are calculated in global coordinate system. They are only equal to principal stress if you do coordinate transformation so that shear stress are zero in the stress tensor. As Ansys employee, I'm not allowed paste any third party link here, but you can find how to transform by googling stress tensor to principal stressn
• Kai
Ansys Employee
This course will help. https://courses.ansys.com/index.php/courses/stress-and-local-equilibrium/n
• HarsihilZLHZ
Subscriber
got itnThanks Kai.n