Abstract :
Independent polynomial spline approximation of displacement and interlaminar tractions
is proposed for stress analysis in laminates with open holes. Spline approximation eliminates
the inter element compatibility problems leading to unsatisfactory finite element results in the
presence of field singularities. Spline approximation offers continuity of displacement, strain and
stress fields within homogeneous domains preserving, at the same time, the advantages of local
approximation, such as sparsity of the resulting system of equations. Three dimensional full field
solution is obtained. Converged stresses and consistent boundary conditions, such as interlaminar
traction continuity, are displayed. A closed form asymptotic solution, valid in the vicinity of the
hole edge at the interface of two orthotropic plies of arbitrary thickness has been developed to verify
the spline approximation based full field solution. Excellent agreement has been observed for
interlaminar stresses in a [45/-451, AS4/3501-6 laminate under uniaxial tension. The polynomial
spline approximation, ideally suited for problems concerned with the singular solution behavior,
has been applied to three dimensional stress analysis in practical composites containing tens of plies
