## Strain Energy Method (Castigliano’s Theorem) | Beam Deflection

Engr. Alberto Castigliano

Italian engineer Alberto Castigliano (1847 – 1884) developed a method of determining deflection of structures by strain energy method. His *Theorem of the Derivatives of Internal Work of Deformation* extended its application to the calculation of relative rotations and displacements between points in the structure and to the study of beams in flexure.