NSF Young Investigator: Nondestructive Evaluation of Polymer Composites

小行星9457156 本研究的目的是开发和实施一种非接触的，无损的方法来评估复合材料在原位固结过程中的层间粘结。 将机载声-超声技术应用于铺带闭环控制。 在这项研究的早期阶段，重点将是发展一个更好的了解空气中的超声波检测复合材料中的缺陷。 将建立一个理论模型，将机载声-超声操作参数与产生的应力波联系起来，并进行实验验证。 第二阶段的研究将涉及传感和评估债券质量离线使用拟议的空气接触无损检测方法。 将制造和测试不同厚度且最顶层粘合不良的样本。 结合强度的非破坏性评价将与结合强度的机械试验进行比较。 在最后阶段，所提出的空气接触无损检测方法将被集成到现有的磁带铺设设备。 在实验技术的统计设计之后，将开发经验过程模型并实施闭环控制算法。 这项研究在几个方面都很重要。 在通过原位固结处理先进材料时，充分的层间粘结对部件结构完整性至关重要。 因为这些材料的成本高，所以期望在加工期间监控部件质量。 在加工过程中发现的缺陷可以作为过程控制计划的一部分立即返工;从而提高产量并减少废料和成本。 非接触式方法还提供了远程站点的便携性和在线（在制造期间）感测能力。 此外，类似的方法可应用于其他原位固结和粘结工艺。

9457156 Mantell The goal of this research is to develop and implement a noncontact, nondestructive method for evaluating interlaminar bonding during in-situ consolidation of composites. An airborne acousto-ultrasonic technique will be implemented in closed loop control of tape laying. In the early phases of this research, the focus will be on developing a better understanding of airborne ultrasonic waves for detecting defects in composites. A theoretical model relating airborne acousto-ultrasonic operating parameters to the resulting stress wave will be developed and experimentally validated. The second phase of the research will entail sensing and evaluating bond quality off line using the proposed air contact NDE method. Specimens of varying thickness with an poorly bonded top most layer will be manufactured and tested. Nondestructive evaluation of bond strength will be compared with mechanical tests of the bond strength. In the final phase, the proposed air contact NDE method will be integrated into an existing tape laying apparatus. Following statistical design of experiment techniques, an empirical process model will be developed and a closed loop control algorithm implemented. This research is significant on several fronts. In processing of advanced materials via in-situ consolidation, adequate interlaminar bonding is critical to part structural integrity. Because cost of these materials is high, it is desirable to monitor part quality during processing. Defects identified during processing can be reworked immediately as part of the process control scheme; thereby improving yields and reducing scrap and costs. A noncontact method also offers portability to remote sites and on line (during manufacture) sensing capabilities. Moreover, similar methodologies could be applied to other in-situ consolidation and bonding processes.