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

交通运输行业要求减轻结构重量，具有类似的安全标准和更长的维护间隔。这一目标可以通过轻量化的结构和先进的材料来实现。与传统材料相比，这些材料显示出新的和其他的缺陷。因此，必须开发适应或新颖的无损检测(NDT)方法。本项目旨在开发一种适用于纤维增强塑料(FRP)快速非接触检测的方法，该方法基于脉冲剪切仪测量板波和横波。对捕获的波型的解释需要深入了解波场的传播以及FRP部件中波与缺陷之间的相互作用机理。解决了这个反问题后，就有可能在定义明确的时刻从单个波型中提取有关几何特征(深度、大小、形状)的信息。为了发展这种方法，不可避免地要研究激光产生的板波和横波的优化产生与方向相关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.