Collaborative Research: Interactions between a Propagating Matrix Crack and Inclusions in Particulate Composites: Experiments and Modeling

目标和办法：众所周知，聚合物基颗粒复合材料的宏观响应是由微观力学控制的。因此，连接宏观和微观尺度是设计具有微米和亚微米尺寸填料的下一代材料的核心。 最近的调查填充聚合物产生违反直觉的断裂韧性的结果时，填料的特性，如尺寸和填料基质的粘附强度是不同的。 这激发了建议的深入研究如何传播裂纹与嵌入式夹杂物在低和高速率加载下的相互作用。刚性夹杂物在一个相对柔顺的矩阵将在这项研究中使用实验和计算方法的目标。 实验工作将包括断裂过程的宏观（光学干涉测量法，高速成像）和微观（显微镜，表面轮廓仪）测量方面。裂纹-夹杂物相互作用问题的边界元分析将在计算上解决。 测量和计算将协同用于识别新的故障机制以及验证流行的。 更广泛的社会影响：基于聚合物的颗粒复合材料在广泛的应用中被发现，例如生物水泥、导电粘合剂、复合结构泡沫、耐刮擦涂层、固体推进剂、纳米复合材料等。了解一般的机械特性，特别是失效特性，对于涉及这些材料的结构系统的安全性和可靠性至关重要。 拟议的研究旨在通过奥本大学和S大学的研究人员之间的合作来解决上述问题。亚拉巴马。 在这个项目中，学生将接受材料加工，材料的机械和光学表征以及数值建模方面的培训。将鼓励属于代表性不足群体的学生参加该项目。 研究成果将通过档案期刊、专题讨论会和万维网传播。

Objectives and approaches: It is well known that macro scale responses of polymer-based particulate composites are controlled by micro scale mechanics. Hence bridging macro and micro scales is central to the design of next generation materials with micron and sub-micron size fillers. Recent investigations on filled polymers have produced counterintuitive fracture toughness results when filler characteristics such as the size and filler-matrix adhesion strengths are varied. This has motivated the proposed in depth study on how a propagating crack interacts with embedded inclusions under low and high rates of loading. Stiff inclusions in a relatively compliant matrix will be targeted in this research using experimental and computational methods. The experimental work will include aspects of macro (optical interferometry, high-speed imaging) and micro (microscopy, surface profilers) measurements of the fracture process. Boundary element analyses of crack-inclusion interaction problems will be addressed computationally. The measurements and computations will be utilized synergistically for identifying new failure mechanisms as well as validating the prevailing ones. Broader societal impact: Polymer-based particulate composites are found in a wide range of applications as biocements, electrically conducting adhesives, syntactic structural foams, scratch resistant coatings, solid propellants, nanocomposites, to name a few. Understanding the mechanical characteristics in general and failure properties in particular is central to the safety and reliability of structural systems involving these materials. The proposed research is aimed towards addressing the above mentioned issues through collaboration between researchers at Auburn University and Univ of S. Alabama. During this project, students will be trained in materials processing, mechanical and optical characterization of materials as well as numerical modeling. Students belonging to underrepresented groups will be encouraged to participate in the project. Research outcome will be disseminated through archival journals, presentations at focused symposia, and world-wide-web.