2017-09-182017-09-182006GARCIA, Ronaldo Alves; SOTOMAYOR, Jorge; LLIBRE, Jaume. Lines of principal curvature on canal surfaces in R3. Anais da Academia Brasileira de Ciências, Rio de Janeiro, v. 78, n. 2, p. 405-415, 2006.0001-3765http://repositorio.bc.ufg.br/handle/ri/12488In this paper are determined the principal curvatures and principal curvature lines on canal surfaces which are the envelopes of families of spheres with variable radius and centers moving along a closed regular curve in R3. By means of a connection of the differential equations for these curvature lines and real Riccati equations, it is established that canal surfaces have at most two isolated periodic principal lines. Examples of canal surfaces with two simple and one double periodic principal lines are given.engAcesso AbertoRiccati equationPrincipal curvature linesCanal surfacesEquação de RiccatiLinha de curvatura principalSuperfície canalArtigo