Preliminary evaluation of fatigue life gages used for beam life prediction

The present state of the art in material failure in structures has introduced the fatigue life gage. This sensor, an integrating fatigue damage device, monitors the cumulative fatigue damage of an element of structure to which it is bonded. The main objectives of this preliminary study were to initiate the investigation of these sensors and evaluate equipment needed. The report contains some characteristics of the sensors not discussed in the applications note from the manufacturer and instrumentation difficulties in use in the field. Conclusions drawn from the study are as follows: (1) The fatigue life gages suffer instrumentation difficulties at small strain levels; and, (2) The study should be extended at high strain levels and at longer specimen life.