000015997 001__ 15997
000015997 005__ 20161115135335.0
000015997 04107 $$aeng
000015997 046__ $$k2013-06-12
000015997 100__ $$aGreco, L.
000015997 24500 $$aAn Unlocked Implicit G1 Continuity Multi Patch B-Spline Interpolation for the Analysis of 3D Kirchhoff Love Rod Elements

000015997 24630 $$n34.$$pComputational Methods in Structural Dynamics and Earhquake Engineering
000015997 260__ $$bNational Technical University of Athens, 2013
000015997 506__ $$arestricted
000015997 520__ $$2eng$$aWe present a multi patch assumed strain formulation (with implicit G1 -continuity at the ends of the element) for 3D space Kirchhoff-Love rod; rotations are introduced at the ends of the element as degree of freedom similarly to the Hermitian interpolation for Euler Bernoulli beam problem. In this way the G1 continuity is ensured. Due to the general curved geometry a strong coupling appears in the membrane-flexural-torsion (m-f-t) problem, so that a pure displacement formulation leads in general to a locked element (membrane, flexural and torsion locking phenomena can occur). The multi patch approach presented, based on G1 continuity (low degree of continuity), does not present locking in contrast to the B-Spline (high degree of continuity) element, in a pure displacement approach. However, both the approaches present spurious mode in the deformations, i.e. in the stress resultants. In order to avoid this pathology we adopt a standard assumed strain formulation (or B-bar) approach, projecting the tangent strain measures onto lower degree spaces, (by means of standard L2 projections). In particular, considering a polynomial degree interpolation (p) for the displacements, the membrane and torsional strain measures are projected on a (p-1) space, while the two flexural strain measures are projected on a (p-2) space. In this way a very easy definition of the B-bar operators is attained, since the integrations are performed numerically. The strategy is very appealing for the design of free-locking general curve rod elements, and it provides very accurate results for different polynomial degrees as it is shown by means of presented example.

000015997 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000015997 653__ $$aIsogeometric analysis, Kirchhoff-Love rod, G1 multi patch analysis, geometric continuity, locking, assumed strain formulation

000015997 7112_ $$aCOMPDYN 2013 - 4th International Thematic Conference$$cIsland of Kos (GR)$$d2013-06-12 / 2013-06-14$$gCOMPDYN2013
000015997 720__ $$aGreco, L.$$iCuomo, M.$$iImpollonia, N.
000015997 8560_ $$ffischerc@itam.cas.cz
000015997 8564_ $$s1078556$$uhttps://invenio.itam.cas.cz/record/15997/files/2081.pdf$$yOriginal version of the author's contribution as presented on CD, section: SC-MS 17 ISOGEOMETRIC METHODS
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000015997 962__ $$r15525
000015997 980__ $$aPAPER