Clapeyron's theorem

Clapeyron's theorem

[kla·pā·rōnz ‚thir·əm] (mechanics) The theorem that the strain energy of a deformed body is equal to one-half the sum over three perpendicular directions of the displacement component times the corresponding force component, including deforming loads and body forces, but not the six constraining forces required to hold the body in equilibrium.