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

该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的方法，如分层，疲劳和其他损伤。 压电换能器技术提供了一种用于在这些传感器安装在材料结构上或嵌入材料结构内时感测诸如应力、应变和弹性的各种结构特性的手段。 由于制造不当、工作循环磨损、冲击和材料腐蚀，结构可能会退化。 嵌入式传感器可以用于向结构复合部件发出可能损坏的变化信号，并且允许独立于部件的远程几何形状的离线诊断，使得诊断仪器不需要具有针对单个部件的记录。 该项目使用高频声信号来诊断损坏，校准局部属性（密度，厚度，刚度）。 来自压电装置的标准声学测试脉冲可用于探测位于脉冲发生器和传感器之间的损坏。 通过仅使用接收信号的前导部分，可以避免几何相关混响的影响。 这大大简化了对反应变化的解释，将其作为结构退化的线索。 正在寻求的先进结构监测概念在民用运输业的飞机、汽车、卡车和船只以及商业航天业的助推器和卫星方面具有商业用途的潜力。 其他应用领域包括在承重桥梁、复合铁路汽车以及轻质高强度结构复合材料正在取代重型金属结构的许多其他领域中使用结构复合材料。

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.