Elastomers often exhibit large stretchability but are not typically designed with robust energy dissipating mechanisms. As such, many elastomers are sensitive to the presence of flaws: cracks, notches, or any other features that cause inhomogeneous deformation significantly decrease the effective stretchability. To address this issue, we have dispersed voids into a silicone elastomer matrix, thereby creating a “negative” composite that provides increased fracture resistance and stretchability in pre-cut specimens while simultaneously decreasing the weight. Experiments and simulations show that the voids locally weaken the specimen, guiding the crack along a tortuous path that ultimately dissipates more energy. We investigate two geometries in pre-cut specimens (interconnected patterns of voids and randomly distributed discrete voids), each of which more than double the energy dissipated prior to complete rupture, as compared to that of the pristine elastomer. We also demonstrate that the energy dissipated during fracture increases with the volume fraction of the voids. Overall, this work demonstrates that voids can impart increased resistance to rupture in elastomers with flaws. Since additive manufacturing processes can readily introduce/pattern voids, we expect that applications of these elastomer–void​ “composites” will only increase going forward, as will the need to understand their mechanics.

弹性体通常表现出大的可拉伸性，但是通常没有设计成具有强大的能量耗散机制。因此，许多弹性体对缺陷的存在很敏感：裂纹，缺口或其他导致不均匀变形的特征会明显降低有效拉伸性。为了解决这个问题，我们将空隙分散到有机硅弹性体基质中，从而创建了一种“负性”复合材料，该复合材料可在预切割样品中提供更高的抗断裂性和可拉伸性，同时降低重量。实验和模拟表明，空隙会局部削弱试样，沿着曲折的路径引导裂纹，最终耗散更多的能量。我们研究了预切割试样中的两种几何形状（空隙的互连模式和随机分布的离散空隙），与原始弹性体相比，每种材料在完全破裂之前耗散的能量要多一倍。我们还证明，断裂过程中耗散的能量随空隙的体积分数增加而增加。总的来说，这项工作表明，空隙可以赋予具有缺陷的弹性体以更高的抗断裂性。由于增材制造工艺很容易引入/形成空隙，因此我们预计这些弹性体-空洞的``复合材料''的应用只会增加，理解其机理的需求也会不断增加。这项工作表明，空隙可以使具有缺陷的弹性体具有更高的抗破裂性。由于增材制造工艺很容易引入/形成空隙，因此我们预计这些弹性体-空洞的``复合材料''的应用只会增加，理解其机理的需求也会不断增加。这项工作表明，空隙可以使具有缺陷的弹性体具有更高的抗破裂性。由于增材制造工艺可以很容易地引入/形成空隙，因此我们预计这些弹性体-空洞的``复合材料''的应用只会增加，理解其力学的需求也会不断增加。