Deterministic and Probabilistic Investigation on Multiple Crack Interactions in a Semi-Infinite Domain

The investigation of multiple crack interactions in fracture mechanics is important to predict the safety and reliability of structures. This study aims to investigate the interactions of multiple parallel cracks in a semi-infinite domain in both deterministic and probabilistic ways by using an automated finite element modeling procedure and the Monte Carlo simulation. The stress intensity factor is considered as an indicator of failure and accurately evaluated by using the domain integral technique. The variation of the stress intensity factor according to the position, the length, and the number of cracks is demonstrated. In a probabilistic investigation, the effects of the number of cracks, the random distribution of the crack lengths, and the crack interactions to the failure probability are studied for a semi-infinite domain. The stress redistribution among multiple cracks, the effect of unevenly distributed crack lengths, and the combined effect of crack length uncertainties and a crack shielding effect have been examined.

Estimation of Apparent Fracture Toughness of Alumina Based Ceramic Laminate

The main aim of this contribution is the fracture behavior of layered ceramic composite with residual stresses. The influence of laminate composition on crack propagation (influence of material interfaces on crack shielding, effect of residual stresses, etc.) was investigated. The crack behavior was described by procedures based on linear elastic fracture mechanics (LEFM) and generalized LEFM. Computations were performed in 2D geometry under plain strain assumptions. For determination of the real crack front shape during the crack propagation the three dimensional FEM models were developed. Both (2D/3D) approaches were compared and differences were closely discussed. The influence of laminate composition with residual stresses on critical values for crack propagation through laminate interfaces was also determined. The results obtained can be used for a design of new layered composites with improved resistance against propagation of cracks.