Ultrasonic Evaluation of Delimination Defects at FRP/Concrete Interface

FRP/混凝土界面脱层缺陷的超声评估

• 批准号: 9800345
• 负责人: Mo Ehsani
• 金额: $ 15万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9800345&HistoricalAwards=false
• 关键词: Ultrasonic; Evaluation; Delimination; Defects; FRP

9800345 Ehsani Fiber Reinforced Composites (FRP) are fast becoming a viable new construction material. Perhaps the most suitable area of application for these materials is in the field of strengthening and rehabilitation of existing civil structures. Numerous field applications have demonstrated that FRPs can result in some 30% cost savings compared to conventional rehabilitation techniques. The success of the technique depends to great extend on the quality of the construction, and in particular, the epoxy joint which had to transfer the stresses from the FRP plate to the substrate. Consequently, there is a great need for development of Non-Destructive Evaluation (NDE) techniques which could detect any flaws or delaminations in the epoxy bond line. Such a system could not only be used to ensure quality of construction, but could also help with detection of any damage that may form during the life of the structure by environmental effects such as ultraviolet rays, moisture penetration, etc. The quality of rehabilitation will be monitored nondestructively by ultrasonic inspection of internal defects, voids and delaminations, when the specimen is not homogeneous, such as a composite layer that is to be used, evaluation of interfaces between two different materials or layers is a much harder job. It is specially difficult if the two interfaces are debonded or weakly bonded but are in close contact with each other forming what is called "kissing" or "slip" bonds. Hence for this applicaiton the Lamb wave scanning technique appears to be the superior technique. ***

9800345 Ehsani 纤维增强复合材料 (FRP) 正在迅速成为一种可行的新型建筑材料。 也许这些材料最合适的应用领域是现有土木结构的加固和修复领域。 大量现场应用表明，与传统修复技术相比，FRP 可以节省约 30% 的成本。 该技术的成功在很大程度上取决于施工质量，特别是必须将应力从 FRP 板转移到基材的环氧树脂接头。 因此，非常需要开发能够检测环氧树脂粘合线中的任何缺陷或分层的无损评估（NDE）技术。 这样的系统不仅可以用于确保施工质量，还可以帮助检测结构在使用寿命期间可能因环境影响（例如紫外线、湿气渗透等）而形成的任何损坏。当样本不均匀（例如要使用的复合层）时，将通过内部缺陷、空隙和分层的超声波检查来非破坏性地监测修复质量。 两种不同材料或层之间的界面是一项困难得多的工作。 如果两个界面脱粘或弱结合但彼此紧密接触形成所谓的“接吻”或“滑移”结合，则特别困难。 因此，对于该应用，兰姆波扫描技术似乎是更优越的技术。 ***