Shape optimization for a composite crack-length sensor

Conductive polymeric sensors can be used as crack-length gages. They have the advantages of being inexpensive, versatile in size and require inexpensive instrumentation. They also measure crack length continuously. The shape of these gages can be varied in several ways to improve their sensitivity. The gages with the ‘optimized’ or tapered shape overcome the principal disadvantages of rectangular gages, namely poor sensitivity at small crack lengths.