The fracture toughness of a cordierite square lattice

A single-edge-notch bend test was developed for the measurement of fracture toughness of a ±45° square lattice made from an elastic-brittle solid. The finite element method was used to obtain the K-calibration for an orthotropic elastic solid, with elastic constants equal to that of the ±45° square lattice. Finite element simulations were also used to predict the fracture strength of the cracked lattice, with failure dictated by the tensile strength of the cell-wall material. The conditions for K-dominance and for failure by a net-section strength criterion of the specimen were thereby determined. A set of fracture tests on single-edge-notch bend specimens made from the ceramic cordierite validate the predictions. The measured fracture toughness of the cordierite lattices scales linearly with the stockiness of the lattice.