Interaction-mechanisms of laser-generated plate- and shearwaves with imperfections in fibre-reinforced plastics

交通运输业要求降低结构重量，同时具有可比的安全标准和更长的维护间隔。这一目标可以通过轻质结构和先进材料来实现。与传统材料相比，这些材料显示出新的和其他缺陷。因此，适应或新的无损检测（NdT）的方法必须开发。该项目旨在开发一种合适的NdT方法，用于快速和无接触地检测纤维增强塑料（FRP），该方法基于使用脉冲剪切仪测量板波和剪切波。对捕获的波图案的解释需要彻底了解波场传播以及波与FRP部件中缺陷之间的相互作用机制。有了这个逆问题的解决，它将有可能提取信息的几何特征（深度，大小，形式）从一个单一的波图案在一个明确的时刻。对于该方法的发展，它是不可避免的调查优化的激光产生的板和剪切波的产生相对于取向依赖的灵敏度和测量分辨率。

Transportation industry requires a reduction of structural weight with comparable security standards and longer maintenance intervals. This goal can be achieved through lightweight constructions and advanced materials. These materials show new and other defects compared to conventional materials. Therefore adapted or novel non-destructive testing (NdT) methods have to be developed. This project aims at the development of a suitable NdT-method for fast and contact-free testing of fibre-reinforced plastics (FRP) based on the measurement of plate- and shear-waves with pulsed shearography.The interpretation of the captured wave patterns requires the thorough understanding of the wavefield propagation as well as the interaction-mechanisms between the waves and defects in FRP-parts. With this inverse problem solved, it will be possible to extract information about the geometrical features (depth, size, form) from a single wave pattern at a well-defined instant of time. For the development of the method it is inevitable to investigate optimized laser-generated plate- and shear-wave generation with respect to the orientation-dependent sensitivity and measurement resolution.