Why use Castigliano's theorem

You can apply Castigliano's theorem if you should have some background with :
  • Deflection of a beam/cylinder due to axial loading, bending, torsion.
  • For calculating the normal moment of inertia.
  • For calculating the polar moment of inertia.
  • Deriving equations for linear changes in quantities.
  • Using singularity functions but it is often used in conjunction with Castigliano’s Theorem.
  • Determining the deflection of beams 
  • Castigliano’s Theorem uses strain energies at the locations of forces to determine the deflections.
  • For determining of deflections for objects with changing cross-sectional areas.