Stress analysis and vibration of elastic and viscoelastic systems (Composite materials and structures)

本研究计划的第一个目标是提供一个集成的设计和制造过程的先进复合材料结构，提供高性能，成本效益，低损耗，和传感能力，可以检测和定位发生的损伤原位的发展。第二个目标是开发在层内具有纤维取向变化的复合结构（除了跨层的纤维取向变化之外）。 第一个目标的工作将涉及将纳米颗粒掺入到聚合物复合材料的基体树脂中，以提高聚合物基体的断裂韧性、导电性和导热性。然后使用预浸料机将该改性的聚合物基质掺入长纤维如碳纤维和玻璃纤维中。将使用自动纤维铺放机处理组合的改性基质和纤维，以制造常见形状的复合材料结构，例如板、壳或管。使用机器进行加工可以提高整个结构中材料性能的均匀性。 将利用材料的增强的导电性来提供感测能力。这种感测能力将使得能够在结构处于操作中时检测和定位所发生的损坏（即，原位或飞行中的损坏检测和定位）。与目前的无损检测技术相比，这种方法的优点是材料在结构中的每个点都是敏感的，这使得传感是通用的，而不是局部的。 第二个目标的工作将涉及层内纤维的转向。这允许不仅跨层而且在层内改变纤维取向的能力。将开发优化程序，以提高复合材料结构的能力，使用这种新的方法。自动纤维铺放机的使用允许制造这种结构。 将进行测试以验证理论。复合材料和结构的发展将取得阶段性进展。

The first objective of this research program is to provide an integrated design and manufacturing procedure for the development of advanced composite structures that offer high performance, cost efficiency, low wastage, and sensing capability that can detect and locate the occurrence of damages in-situ. The second objective is the development of composite structures that have variation in fiber orientation within a layer (in addition to changes in fiber orientation across layers). The work for the first objective will involve the incorporation of nanoparticles into the matrix resin of the polymer composites to enhance the fracture toughness, electrical conductivity, and thermal conductivity of the polymer matrix. This modified polymer matrix is then incorporated into long fibers such as carbon fibers, and glass fibers using a prepreg machine. The combined modified matrix and fibers will be processed using automated fiber placement machine to make composite structures of common shapes such as plates, shells or tubes. The use of machines for processing improves the uniformity of the material properties throughout the structure. The enhanced electrical conductivity of the materials will be utilized to provide sensing capability. This sensing capability will enable the detection and location of incurring damages while the structure is in operation (i.e. in-situ or in-flight damage detection and location). The advantage of this method as compared to current NDT technologies is that the material is sensitive at every point in the structure, which makes the sensing to be universal, rather than local. The work for the second objective will involve the steering of fibers within a layer. This allows the ability to vary the fiber orientation not only across the layers but also within a layer. Optimizaton procedure will be developed to augment the capability of composite structures using this new approach. The use of automated fiber placement machine allows the manufacturing of such a structure. Testing will be done to validate the theories. Step advances for composite materials and structures developments will be made.