Link to Index Page

Buckling of inflated air bag

FROM:
Fehmi Cirak and Michael Ortiz (Aeronautical Laboratories, California Institute of Technology, Pasadena),

“Fully C1-conforming subdivision elements for finite dedormation thin-shell analysis”, International Journal for Numerical Methods in Engineering, Vol. 51, pp 813-833, 2001

ABSTRACT: We have extended the subdivision shell elements of Cirak, Ortiz and Schroder [20] to the finite-deformation range. The assumed finite-deformation kinematics allows for finite membrane and thickness stretching, as well as for large deflections and bending strains. The interpolation of the undeformed and deformed surfaces of the shell is accomplished through the use of subdivision surfaces. The resulting ‘subdivision elements’ are strictly C1-conforming, contain three nodes and one single quadrature point per element, and carry displacements at the nodes only. The versatility and good performance of the subdivision elements is demonstrated with the aid of a number of test cases, including the stretching of a tension strip; the inflation of a spherical shell under internal pressure; the bending and inflation of a circular plate under the action of uniform pressure; and the inflation of square and circular airbags. In particular, the airbag solutions, while exhibiting intricate folding patterns, appear to converge in certain salient features of the solution, which attests to the robustness of the method.

Page 79 / 256