SBIR Phase I: A New Approach to Local Area Damage Detection in Composite Structures

这个小型企业创新研究第一阶段项目将开发一种新的方法来检测和分类结构复合材料部件的损伤，从而提供一种检测结构退化(如分层、疲劳和其他损伤)的方法。当传感器安装在材料结构上或嵌入材料结构中时，压电传感器技术提供了一种传感各种结构特性的方法，例如应力、应变和弹性。结构可能会由于制造不当、占空比磨损、冲击和材料腐蚀而退化。嵌入式传感器可以用来用信号通知结构组合部件的可能损坏的变化，并允许独立于部件的远程几何形状进行离线诊断，因此诊断仪器不需要具有针对单个部件的记录。该项目使用高频声学信号来诊断损伤，并针对局部属性(密度、厚度、硬度)进行校准。来自压电器件的标准声学测试脉冲可以用来探测脉冲发生器和传感器之间的损伤。通过仅使用接收信号的前导部分，可以避免依赖于几何形状的混响的影响。这大大简化了将反应中的变化解释为结构退化的线索。正在寻求的先进结构监测概念有可能在民用运输业中用于飞机、汽车、卡车和船只，以及在商业航天工业中用于助推器和卫星。其他应用领域包括结构复合材料在承重桥梁、复合材料轨道车辆和许多其他领域的应用，在这些领域，轻质高强度结构复合材料正在取代重型金属结构。

This Small Business Innovation Research Phase I project will develop a new approach to detection and classification of damage to a structural composite part, thus providing a means for sensing structural degradation such as delaminations, fatigue and other damage. Piezoelectric transducer technology provides a means for sensing various structural properties such as stress, strain, and elasticity when these sensors are mounted on, or embedded within, a material structure. Structures may degrade due to improper manufacture, duty cycle wear, impacts, and material corrosion. Embedded sensors may be used to signal changes, likely to be damage, to a structural composite part and permit off-line diagnosis independent of the long-range geometry of the part, so that the diagnostic instrument need not have records for individual parts. This project uses high-frequency acoustic signals to diagnose damage, calibrating for local properties (density, thickness, stiffness). Standard acoustic test pulses from the piezoelectric devices can be used to probe for damage located between pulse generators and sensors. By using only the leading portion of the received signal it is possible to avoid the effects of geometry-dependent reverberation. This greatly simplifies the interpretation of changes in the response as clues to structural degradation. The advanced structural monitoring concepts being sought have potential of commercial use in the civil transportation industry for aircraft, automobiles, trucks and boats, and in the commercial space industry for boosters and satellites. Other application areas include the use of structural composites in load-bearing bridges, composite railroad cars, and numerous other areas where light-weight high-strength structural composites are replacing heavy metallic structures.