Variational theory of motion of curved, twisted and extensible elastic rods

Abstract The variational theory of 3-D motions of curved twisted and extensible elastic rods is obtained based entirely on the kinematical variables of position and rotations. The constitutive relations that define the resistive couples and the axial force as gradients of the strain energy function are established. A candidate for the strain energy function, derived on the basis of classical assumptions, is presented.