Modelling the effect of layer strength distribution on the brick-and-mortar failure regimes and properties

Abstract

Brick-and-Mortar structures are of high interest because their staggered multi-material arrangement can result in a remarkable combination of high strength and high toughness. Synthetic replication of these structures with high geometric control has been made possible recently with the advances in multi-material Additive Manufacturing (AM). However, very little is known on how inherent material variation in the constituent materials, which can be significant in AM, affects the structure response.In this work, we use a semi-analytical model to theoretically show that a variation in the strength of the layers in a Brick-and-Mortar structure has a significant effect on the failure response of the structure. It can lead to changes in failure regimes and negatively impact the mechanical properties, such as decrease the strain to failure or decrease the yield stress. This is particularly pronounced when the material behaviour is situated close to the transition point between failure regimes. We then present an experimental method to capture strength variability in the layer material and demonstrate that the incorporation of this variability into the semi-analytical model improves our prediction of the failure response of the structure, as compared to experiments.