11 March 2017

Hollow shaft vs Solid shaft

The hollow shaft contains the same amount of material all at the ends if hollow and a solid shaft are of the same weight whereas in the solid shaft distributed the material is uniformly throughout the shaft leaves little material at the ends. Difference between both of them is resistance to bending, resistance to torsion. Let us have a deep insight into the difference between the hollow and solid shaft.

Difference between the hollow shaft and solid shaft : 

  • The material at the centre is removed in the hollow shaft and spread at large radius therefore, hollow shafts are stronger than solid shafts with the same weight.
  • The stiffness of the hollow shaft is more than the same weight solid shaft.
  • The strength of the hollow shaft is more than the same weight solid shaft.
  • The natural frequency of the hollow shaft is higher than the solid shaft with the same weight.
  • Hollow shaft is costlier than the solid shaft.
  • The diameter of the hollow shaft is more than a solid shaft and require more space.
  • Hollow shafts have a more polar moment of inertia, which enables them to transmit more torque than solid shafts.
  • Hollow shafts do not transfer more power but the power to weight ratio of hollow shafts is more as compared to the solid shaft.
  • Solid shafts, when subjected to bending, are stronger than that of the hollow shaft.

Depends on the application of the shaft :

Hollow shaft better for structural applications because it can beat the same loads as a solid shaft for lesser weight. Example: Rollcage of offroad vehicles.

The solid shaft is better for power transmission when compared to the hollow shaft. Example: Driveshaft

For the load-bearing type of shaft, it is always better to choose hollow shaft because it has higher stiffness and rigidity and can resist slightly higher bending moments. 

A shaft for transmission of torque like crankshafts, driveshafts, choosing a solid shaft is always better because it has higher torsional stiffness.