A Simple Geometrically Exact Displacement Based Shell Finite Element

Resumo

This paper presents a modification of the T6-3iKL element based solely on displacements. It is a nonconforming triangular element with 6 nodes and a quadratic displacement field enhanced by a bubble function. Its coefficients are eliminated with three scalar rotation parameters at the mid-side nodes. The element approximates the Kirchhoff-Love shell model in the large displacement domain with only 21 DoFs . The rotation-continuity between adjacent elements is enforced at mid-side nodes, allowing for multiple branch connections in the mesh. The element allows the adoption of different material constitutive equations. The model is numerically implemented, and the results are compared to varying references in multiple examples, showing the capabilities of the formulation. The original desirable properties of the T6-i3KL element are preserved, which are the lack of penalties or Lagrange multipliers, a simple exact nonlinear kinematics, a relatively small number of DoFs, the possibility of using 3D material models, and is easily connected with multiple branched shells and beams.