Kirchhoff rods with nonhomogeneous cross section
  The Kirchhoff's theory for thin, inextensible, elastic rods with nonhomogeneous cross section is studied. The Young's and shear moduli of the rod are considered to vary radially, and it is shown that an analytical solution for the constitutive relations can be obtained for circular cross section and constant Poisson's ratio. We comment on possible applications of our results. 
Alexandre F. da Fonseca, Coraci P. Malta