Ubaid Jabir, Wardle Brian L, Kumar S
Department of Mechanical and Materials Engineering, Khalifa University of Science and Technology, Masdar Institute, Abu Dhabi, 54224, UAE.
Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Sci Rep. 2018 Sep 11;8(1):13592. doi: 10.1038/s41598-018-31819-2.
Material tailoring of bondlayer compliance is a known effective route to enhance performance of multilayers, and here spatial material-tailoring of compliance and morphology of the adherends is examined. Multimaterial jetting additive manufacturing (AM) allows us to realize for the first time compliance- and morphology-tailored adherends, and evaluate directly the mechanical performance, including failure, of the tensile-loaded multilayers. Adherend compliance-tailoring, unlike bondlayer tailoring, requires additional consideration due to adherend bending stiffness and moment influences on bondlayer stresses. We introduce anisotropic as well as layered/sandwich adherend tailoring to address this dependence. Numerical models show that for both sub-critical and critical bondlengths (at which shear-dominated load transfer occurs through the bondlayer), adherend tailoring reduces peak stresses significantly, particularly peel stress (reductions of 47-80%) that typically controls failure in such systems. At sub-critical bondlengths, the AM-enabled layered/sandwich adherend tailoring shows significantly increased experimental performance over the baseline multilayer: strength is increased by 20%, toughness by 48%, and strain-to-break by 18%, while retaining multilayer stiffness. The adherend tailoring demonstrated here adds to the techniques available to increase the performance of bonded multilayers, suggesting that adherend tailoring is particularly well-suited to additively manufactured multilayers, but can also have application in other areas such as layered electronics and advanced structural composite laminates.
对粘结层柔顺性进行材料剪裁是提高多层材料性能的一种已知有效途径，本文研究了被粘物柔顺性和形态的空间材料剪裁。多材料喷射增材制造（AM）使我们首次能够实现柔顺性和形态剪裁的被粘物，并直接评估拉伸加载多层材料的力学性能，包括失效情况。与粘结层剪裁不同，被粘物柔顺性剪裁由于被粘物弯曲刚度和弯矩对粘结层应力的影响而需要额外考虑。我们引入各向异性以及分层/夹层被粘物剪裁来解决这种依赖性。数值模型表明，对于亚临界和临界粘结长度（在该长度下，剪切主导的载荷传递通过粘结层发生），被粘物剪裁可显著降低峰值应力，尤其是通常控制此类系统失效的剥离应力（降低47 - 80%）。在亚临界粘结长度下，通过增材制造实现的分层/夹层被粘物剪裁相对于基线多层材料显示出显著提高的实验性能：强度提高20%，韧性提高48%，断裂应变提高18%，同时保持多层材料的刚度。本文展示的被粘物剪裁增加了可用于提高粘结多层材料性能的技术手段，表明被粘物剪裁特别适用于增材制造的多层材料，但也可应用于其他领域，如分层电子和先进结构复合层压板。
