An accurate Ritz approach for analysis of cracked stiffened plates

Abstract

• Ritz method is promoted in predicting stress intensity factors of cracked stiffened plates. • Plate domain is assembled in a small number of disjoint subdomains. • Hierarchic polynomials is adopted to locally approximate the displacement field. • Strain energy always converges monotonically and from below. The present paper promotes the capabilities of the Ritz method in accurately predicting the stress intensity factor of cracked plates with either continuously or discretely attached stiffeners. The original plate domain is initially treated as an assembly of a small number of disjoint subdomains, chosen according to the crack and stiffener locations, in order to properly construct Ritz bases accounting for discontinuities. A complete set of hierarchic polynomials is adopted to locally approximate the displacement field within each subdomain, and then the displacement continuity is exactly imposed between subdomains whenever required. The accuracy of the present solutions are confirmed through comparison with published data, when available, and with converged results obtained from developed finite element models. The proposed procedure is further employed to investigate the effect that a propagating crack has on the stress intensity factor as the crack approaches and crosses a stiffener.