A SHEAR-LOCKING FREE ROBUST ISOPARAMETRIC 3-NODE TRIANGULAR ELEMENT FOR GENERAL SHELLS

A shear-locking free isoparametric three-node triangular finite element suitable for both moderately thick and very thin shells is developed. Reissner and Mindlin theory that incorporates transverse shear deformation into the shell formulations is considered. The theory introduces five degrees of freedom, three translations and two rotations, at each node of the element. This isoparametric-based element is well known for its shear-locking effects in thin situations when a full or reduced integration scheme is used. These shear-locking effects are eliminated by imposing a constant transverse shear strain criterion and introducing a shear correction expression in the formulations. The element has shown a robustness in all types of triangular mesh configurations. The numerical results include convergence tests for transverse displacement and moment for shells of rectangular planform for moderately thick and very thin situations. These numerical results are compared with the recently available analytical solutions for moderately-thick and thin shells and Reissner and Mindlin theory-based finite element solutions.