Where is the maximum stress located in a cantilever horizontal hollow tube acted upon by a vertical force and a torque?

In analyzing a cantilever horizontal hollow tube subjected to a vertical load and a torque, it is crucial to consider how these forces impact stress distribution within the structure.

The vertical force creates bending in the tube, leading to tensile and compressive stresses. For a cantilever beam, these stress concentrations are maximum at the fixed support, or built-in end, and will vary across the length. When it comes to a hollow tube, the stress at the upper surface at the built-in end will be at its maximum compressive state, while the lower surface will face maximum tensile stress.

Additionally, the torque introduced can create shear stresses. In a case where both bending and torque are acting on the tube, you will find that the highest stress points occur at both the upper and lower surfaces of the tube at the built-in end. This is a reflection of how each force contributes to stress: the vertical load leads to maximum bending stresses, while the torque contributes to twisting stresses, which are compounded at the ends of the tube.

Therefore, the correct answer highlights that maximum stress resides at both the upper and lower surfaces at the built-in end, due to the combined effects of bending and torsion acting at the location where the tube is fixed.