U.S.-Germany Cooperative Research on the Optimal Generation of Elastic Waves in Structures

该奖项支持张富国教授和斯坦福大学的三名研究生与Peter Hagedorn教授和他的同事以及德国达姆施塔特理工学院力学研究所的学生在机械工程研究方面进行合作。他们正在研究超声波弹性波在结构中的传播，其中波是由内置在结构中的压电体(PZT)产生的。美国研究小组使用PZT产生的波来检测复合材料制成的功能结构中的损伤。德国团队对这种波的传播特别感兴趣，将其作为先进超声波马达设计的一个方面。合作小组将参与使用表面安装和嵌入的压电陶瓷的实验，并开发这些系统的分析模型。由于它们的利益和方法的互补性，这两个小组应该会从这种协调的联合研究中受益。及早发现飞机、桥梁等结构的服役损伤对于延长结构的使用寿命和保证结构的安全使用起着至关重要的作用。显然，损坏检测技术必须是非破坏性的，理想情况下，它们应该便于在日常维护期间在现场执行。超声波的产生是这一诊断过程的一种很有前途的新方法。这项合作研究的结果将加深对压电致超声传播的基本认识，并将为通过控制压电体来产生特定应用的超声波提供基础。

This award supports Professor Fu-Kuo Chang and three graduate students from Stanford University to collaborate in mechanical engineering research with Professor Peter Hagedorn and his colleagues and students of the Mechanics Institute of the Technische Hochschule of Darmstadt, Germany. They are studying ultrasonic elastic wave propagation in a structure, where the waves are generated by piezoelectrics (PZT) built into the structure. The U.S. team uses PZT-generated waves to detect damage in functioning structures made of composite materials. The German team is particularly interested in the propagation of such waves as an aspect of the design of advanced ultrasound motors. The cooperating groups will be involved both in experiments using surface-mounted and embedded piezoceramics and in developing the analytical models of these systems. Because of the complementarity of their interests and approaches, both groups should benefit from this coordinated joint research. Early detection of service-induced damage in structures such as airplanes and bridges plays an essential role in prolonging the lifespan of the structures and in providing safe use of the structures. Clearly damage detection techniques must be non-destructive and ideally they should be convenient to perform on-site during routine maintenance. Ultrasonic wave generation is a promising new approach to this diagnostic process. The results of the proposed cooperative research will improve fundamental understanding of piezo-induced ultrasound propagation, and it will provide the basis for tailoring the production of ultrasonic waves for specific applications by means of controlling the piezo electrics.