1. The problem statement, all variables and given/known data https://en.wikipedia.org/wiki/Cauchy_stress_tensor I dont understand the difference between τxy . τyx , τxz , τzx , τyz , τzy ..What did they mean ? 2. Relevant equations 3. The attempt at a solution taking τxy and τyx as example , what are the difference between them ? They are the same , right ? they mean the shear force shear the xy plane , right ?