Accurate and efficient a posteriori account of geometrical imperfections in Koiter finite element analysis

作者：Garcea G^*; Liguori F S; Leonetti L; Magisano D; Madeo A

来源：International Journal for Numerical Methods in Engineering, 2017, 112(9): 1154-1174.

DOI：10.1002/nme.5550

• Koiter FE method
• geometrical imperfections
• post-buckling
• limit load
• imperfection sensitivity
• finite elements

The Koiter method recovers the equilibrium path of an elastic structure using a reduced model, obtained by means of a quadratic asymptotic expansion of the finite element model. Its main feature is the possibility of efficiently performing sensitivity analysis by including a posteriori the effects of the imperfections in the reduced nonlinear equations. The state-of-art treatment of geometrical imperfections is accurate only for small imperfection amplitudes and linear pre-critical behaviour. This work enlarges the validity of the method to a wider range of practical problems through a new approach, which accurately takes into account the imperfection without losing the benefits of the a posteriori treatment. A mixed solid-shell finite element is used to build the discrete model. A large number of numerical tests, regarding nonlinear buckling problems, modal interaction, unstable post-critical and imperfection sensitive structures, validates the proposal.

• 出版日期2017-11-30