Wireless Crack Propagation Embeddable Sensor

In the recent past, the use of composite materials in aircraft has increased. While composite materials offer many benefits, they are not perfect materials. Micro-cracking can occur in the cooling process of laminate construction. These cracks can spread and new cracks can even form during temperature cycling. Monitoring crack propagation in key locations can increase the safety and reliability of aircraft while reducing the cost to maintain them. An embeddable, remotely powered, miniature, wireless system is what is required. There are two types of crack propagation measurement currently on the market - parallel resistance, and continuity gages. While INVOCON has developed a multitude of miniature wireless systems based on technologies similar to the parallel resistance and continuity gages, there is another approach. It is possible to measure the length of a crack propagation gage using reflected Radio Frequency (RF) energy. This technology can be used to follow two-dimensional or even three-dimensional crack propagation. This method, while more difficult to produce for a Phase I demonstration, provides a simpler path to the Phase II embeddable solution. In addition, the technique can be extended to measure laminate strain with the same sensor, making a much more commercially viable system.