Fracture analysis of complex shaped structures by numerical and experimental methods

Abstract

SummaryThe problem of fracture characterisation of geometrically complex structures is considered. Numerical and experimental strategies are used to evaluate stress intensity factors and elastic fields for cracked thin shell and plate structures. Theoretical analyses, using different order theories, are also performed in order to evaluate stress and energy distributions in the neighbourhood of the crack tip. A geometrically complex strut component is analysed by using a ‘p-convergent’ finite element code based on hierarchic elements and on the high degree of approximating functions. Actual fracture modes, for different crack locations, have been singled out and the elastic fields are compared to those referring to cracked plate and shell structures. An experimental investigation, using the optical method of caustics, has been also performed and stress intensity factors for several crack configurations have been calculated. The numerical investigations have shown the ability of the p-version finite element method to provide accurate computation of local stress values and to quote the convergence of the numerical calculations. The caustics method has confirmed its accuracy for evaluating stress intensity factors, even for complex structures.