Use of capacitance strain gauges for static measurements at high temperatures

Two commercially available capacitance strain gages were tested. Calibration, apparent strain, thermal hysteresis, drift, and maximum temperature were considered. The gages were calibrated on a four point bending beam with direct current heating subjected to pure bending strain. Apparent strain was recorded on a constant strain cantilever, fixed at one end, which could be heated to 1100 C in a furnace. Zero setting drift was determined on the constant strain cantilever. Creep behavior was investigated by applying a CERL gage to an unloaded triangular bending rod with strain of + 3700 micron/m. It is shown that the CERL gage is reliable up to 650 C.