Micro-Eletro-Mechanical Systems (MEMS)

The problem addressed is through-life, non-destructive monitoring of adhesively bonded structures. The concept presented is to produce a mart material cro-electro Mechanical Systems (MEMS) bond degradation sensors positioned in the adhesive bond-line. These MEMS sensors consist of two critical components: 1)the chemical sensor and 2)the CMOS circuitry required for the sensor to be autonomous. The sensors can be applicable to both metal/adhesive and composite/adhesive bonding systems. Adhesive bond line can be as thin as 80 micron. The autonomous sensors will be fabricated to be less than 80 micron thick. This is achieved by internal control circuitry, CMOS for low power requirements, fabricated on wafers that can be backthinned to produces less that 80 micron thick devices. The effect on the bond strength will be minimal since the area that will be taken up by the sensors will be insignificant compared with the total area of the bonded repair or component.The rial ic platform goes through a complete tear down during the Life Extension Program (LEP). The small independent, wireless sensors form a condition Based Maintenance (CBM) health monitoring system. The sensors are permanently installed and can be permanently monitored. The monitoring system will indicate and select the damage location area which will have to be inspected and repaired.