ACX proposes to design, fabricate, and test a sensor with enclosed signal conditioning and amplification electronics for embedding into composite structures. The amplified signal can then be transmitted using either an analog-to-digital converter and a digital fleixble circuitry line, or an RF transmitting device. This method of collecting data maintains the structural integrity, and the materials used for the patented ACX QuickPack packaging and in the flexible circuitry are compatible with the epoxies used in most composites, as has been demonstrated in the past. The most commonly used techniques for non-invasive structural health monitoring include ultrasound devices, but embedded piezoceramic sensors are a very attractive alternative of the future. One of the main reasons of concern when using piezoceramic sensors, though, is the fact that wires are needed to transport the signal from the sensors to an acquiring device. The proposed concept solves this problem in one of two ways. If it is found feasible, then RF transmitting devices will be integrated into the structure, and the sensors are therefore going to be stand-alone. If this solution does not yield the expected results, then a digital line of flexible circuitry can be laid between the sensor and the edge of the structure. ACX's manufacturing technique allows for the inclusion of electroncis within the sensor package, as well as extending flexible, thin cirucit lines from the sensor to the edge of the structure. In this Phase I effort, the main focus will be on determining the best design for this kind of solution, in terms of materials to use, electronics to choose, and sensor placement and size for each structure, and on building test samples. Embedded sensor systems for structural health monitoring are an expanding sector, and ACX can grow into the market by fabricating non-destructive sensor systems. ACX also specializes in structural control and vibration reduction systems, and is therefore qualified to design the algorithms necessary for complete structural health monitoring systems.
