Why is the Hollow shaft is considered more strength than a solid shaft?

Question

This is only for mechanical engineers...

Answer 1

Your question failed to include the conditions under which your question is true: I assume that you meant, "...than a solid shaft of the same weight?"

Both bending and torsional stress theories show that the greatest strength is obtained by the outer fiber of a beam, that is, along the outside diameter for a tubular shape. Therefore, the core metal adds a lot of extra metal for little gain in strength. For a given weight of metal, a tube is generally stronger than a solid shaft.

Some exceptions I can think of:

1. If the wall thickness is too thin to be stable, the tubing would collapse prematurely.

2. Solid shaft is often less expensive to manufacture than thick-walled tube, so there are still plenty of uses for solid shaft.

Answer 2

A solid shaft is stronger than a hollow shaft of the same diameter but may be weaker than a hollow shaft of the same weight (same amount of steel for a given length). There is only one design for a solid shaft but the inside and outside diameters and thickness of a hollow shaft can be optimized to transmit maximum torque.

Answer 3

which shaft is stronger are solid pr hollow shaft

Answer 4

Its an issue of stiffness more so then strength and depends on diameter limitations. Simple moment of inertia calcs will show you.