ひずみ仮定を用いた非圧縮超弾性シェル要素の開発とその評価

抄録

The objective of this paper is to develop a finite strain shell element with its material restricted to hyper-elasticity. This shell element is based on the MITC shell element developed by Bathe in 1984 to perform locking-free behavior using assumed transverse shear strains. In addition to this MITC formulation, an assumed transverse normal strain is introduced to treat thickness change. In this formulation, the transverse normal strain is assumed to be uniform throughout the element, and evaluated at the middle surface using incompressibility condition. Indeterminate pressure, which occurs in incompressible materials, is eliminated at the element level using the plane stress condition. The advantage of this technique is that well-conditioned tangent stiffness for a large strain shell element can be obtained without any additional variables. Numerical analysis was conducted to assess the performance of the present shell element using several examples.