Bio-inspired by abalone nacre, all ceramic brick-and-mortar composites with impressive mechanical properties have been recently manufactured. Albeit comprising only brittle constituents, extrinsic reinforcement mechanisms impart to these nacre-like ceramics high toughness and non-catastrophic crack propagation properties. While several models have been developed to understand the mechanical properties of natural and synthetic brick-and-mortar materials, they have always considered a ductile interface and focused mostly on intrinsic toughening mechanisms. Modeling so far has not captured the extrinsic toughening mechanisms responsible for the properties of nacre-like ceramics. Here we show that the Discrete Element Method (DEM) can account for reinforcement mechanisms such as microcracking and crack deflection, and quantitatively assess strength, initiation toughness and crack growth toughness. Two approaches are studied to enhance strength and toughness of nacre-like ceramics, either by reinforcing the interface globally (an increase of the interface strength) or locally (addition of nano-bridges). We combine the results to provide design guidelines for synthetic brick-and-mortar composites comprising only brittle constituents.

受鲍鱼珍珠质的启发，最近制造了具有出色机械性能的所有陶瓷砖和砂浆复合材料。尽管仅包含脆性成分，但外在的增强机制赋予了这些珍珠母状陶瓷以高的韧性和非灾难性的裂纹扩展特性。虽然已经开发了几种模型来了解天然和合成砖瓦材料的机械性能，但它们始终考虑了韧性界面，并且主要侧重于固有的增韧机理。到目前为止，建模还没有捕捉到与珍珠母状陶瓷有关的外在增韧机制。在这里，我们表明离散元方法（DEM）可以说明诸如微裂纹和裂纹挠度之类的加固机制，并定量评估强度，初始韧性和裂纹扩展韧性。研究了两种方法以通过整体增强界面（增加界面强度）或局部增强界面（增加纳米桥）来增强珍珠母状陶瓷的强度和韧性。我们将结果结合起来，为仅包含脆性成分的合成砖瓦复合材料提供设计指导。