It was realized a corrosion sensing system was essential. Analatom, Inc. decided to find a system with a relatively simple sensor and required minimum signal conditioning. The LPR (Linear Polarization Resistor) came out as the clear winner; it was easily scaled and developed. Laboratory and flight tests with the LPR system have been shown to pick up annual corrosion rates in the sub micron range. In addition to low corrosion rates, the system can detect pitting in aluminum. This pitting causes Tafel constants to become unreliable in aluminum as a method of determining corrosion rate. Alternatives methods are being developed, including: 1) Using a logarithmic amplification stage and analyzing full range of data on the system MCU (Micro Controller Unit), 2) Examining noise on the sensor signal (a well established technique), and 3) Using an AC current on the sensor to determine resistance. The latter (AC) method is the most promising; it requires minimal MCU processing time playing an important role in system life.

At a data collection rate of one reading per minute, the current system allows eight devices to be run on a MCU for ten years of a single 3.6 Volt ˝AA Lithium battery. The system dumps data every three months. The system is also designed to accept other sensors so a complete SHM system is available from one low cost unit. These devices allow phenomena to be recorded: Strain, Humidity, Temperature, Acceleration, Impact, and Fatigue. The system is designed so the MCU connects to standard interfaces such as bus system, Serial, and wireless systems (Motorola’s Zigbee Network). The finished packaged devices are designed fitted as a section of Scotch tape. A minimally trained technician will be able to install Analatom Inc. Smart tape to virtually any structural location on an airframe or high value structure.