Understanding the Macroscopic Dynamics of Ultrasonic Consolidation

该奖项的研究目标是确定和减轻超声波加固制造过程中导致粘结降解的机制。为了实现这一目标，将使用一个多层次的研究框架，将非光滑系统动力学理论与计算算法相结合，并使用一个专门开发的实验模块。在第一级，Hamilton原理与瑞利-里兹方法相结合，开发了一个降阶模型，该模型描述了建筑特征对超声波激励的响应。在第二级，推导了数学模型来描述由于摩擦相互作用而引起的特征的粘滑响应。然后通过实验验证并结合导出的模型，以了解构建特征的几何形状和材料特性的变化如何影响应力和随后的界面粘合。这些知识被用来设计减轻键退化的策略。如果成功，这一努力将提供必要的工具，以克服阻碍广泛使用有前途的超声固化制造工艺的障碍。通过提供一种粘合不同材料的机制，并在金属结构中嵌入电子和纤维增强，超声波加固使制造具有独特性能的机器部件和结构系统成为可能。这包括功能梯度结构、金属基复合材料、纤维嵌入式自适应系统以及对机器和结构的健康监测至关重要的自传感组件。研究成果也将广泛发表，使学生和工程师看到动力学和制造之间的关键联系。此外，还计划通过令人兴奋的活动，将研究与教育结合起来的教育推广活动，通过招收少数民族学生来促进多样性。

The research objective of this award is to identify and mitigate the mechanisms responsible for bond degradation in the Ultrasonic Consolidation manufacturing process. To achieve this objective, a multi-level research framework that combines theories of non-smooth systems dynamics with computational algorithms and a specially-developed experimental module will be used. At the first level, Hamilton's principle is combined with a Rayleigh-Ritz approach to develop a reduced-order model, which describes the build feature's response to ultrasonic excitations. At the second level, mathematical models are derived to describe the stick-slip response of the feature due to frictional interactions. The derived models are then experimentally validated and combined to understand how changes in the build feature's geometry and material properties influence stresses and subsequent interface bonding. The knowledge is used to devise strategies to mitigate bond degradation.If successful, this endeavor will provide the necessary tools to overcome a hurdle that is preventing the broad use of the promising Ultrasonic Consolidation manufacturing process. By providing a mechanism to bond dissimilar materials, and embed electronics and fiber reinforcements in metallic structures, Ultrasonic Consolidation permits manufacturing machine components and structural systems with unique performance capabilities. This includes functionally-graded structures, metal-matrix composites, fiber embedded adaptive systems, and self-sensing components that are essential for the health-monitoring of machines and structures. Research results will also be widely published to enable students and engineers to see the critical link between dynamics and manufacturing. An educational outreach initiative that integrates research with education through exciting activities is also planned to promote diversity through recruitment of minority students.