In the framework of a sine model family, two new three-node beam finite elements
including the transverse normal effect are designed for the analysis of laminated
beams. They are based on a sine distribution with layer refinement and a
second-order expansion for the deflection. The transverse shear strain is obtained
using a cosine function, avoiding the use of shear correction factors. This kinematics
accounts for the interlaminar continuity conditions on the interfaces between layers,
and the boundary conditions on the upper and lower surfaces of the beam. A
conforming FE approach is carried out using Lagrange and Hermite interpolations. It
is important to notice that the number of unknowns is independent of the number of
layers.
Both mechanical and thermomechanical tests for thin and thick beams are
presented in order to evaluate the capability of these new finite elements to give
accurate results with respect to elasticity or finite element reference solutions. Both
convergence velocity and accuracy are discussed and this new finite element yields
very satisfactory results at a low computational cost. In particular, the transverse
stress computed from the constitutive relation is well estimated with regards to
classical equivalent single layer models. This work focuses on the necessity to take
into account the transverse normal stress, especially for thick beam and coupled
analysis.
Keywords
finite element methods, composites, refined sine-based,
layer refinement, transverse normal stress, thermal effects