An estimation of the effect of repeated thermal cycling in the temperature range 20-300 C on the characteristics of strain gages based on polyimide adhesive

The effect of thermal cycling over the temperature range 20-300 C on the characteristics of strain gages based on the polyimide adhesive PIR-2 was investigated. It was found that the sensitivity of unprotected gages fell sharply with increasing number of thermal cycles. Similar results were obtained with protected gages, with a more gradual decrease in sensitivity. For protected gages the sensitivity coefficient was lowered by 2% after 2000 cycles and 4% after 5000 cycles. The maximum shift in the apparent strain characteristics over repeated thermal cycling is negligible.