A two-scale Weibull approach to the failure of porous ceramic structures made by robocasting: possibilities and limits

Martin Genet (1) , Manuel Houmard (1) , Salvador Eslava (2) , Eduardo Saiz (2) , Antoni P. Tomsia (1)

1 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
2 Imperial College London

This paper introduces our approach to modeling the mechanical behavior of cellular ceramics, through the example of calcium phosphate scaffolds made by robocasting for bone-tissue engineering. The Weibull theory is used to deal with the scaffolds' constitutive rods statistical failure, and the Sanchez-Palencia theory of periodic homogenization is used to link the rod- and scaffold-scales. Uniaxial compression of scaffolds and three-point bending of rods were performed to calibrate and validate the model. If calibration based on rod-scale data leads to over-conservative predictions of scaffold's properties (as rods' successive failures are not taken into account), we show that, for a given rod diameter, calibration based on scaffold-scale data leads to very satisfactory predictions for a wide range of rod spacing, i.e. of scaffold porosity, as well as for different loading conditions. This work establishes the proposed model as a reliable tool for understanding and optimizing cellular ceramics' mechanical properties.

Domaines: Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]

Martin Genet, Manuel Houmard, Salvador Eslava, Eduardo Saiz, Antoni P. Tomsia. A two-scale Weibull approach to the failure of porous ceramic structures made by robocasting: possibilities and limits. Journal of the European Ceramic Society, 2013, 33 (4), pp.679-688. ⟨10.1016/j.jeurceramsoc.2013.01.014⟩. ⟨hal-00851004⟩