Fundamental Study on a Foil Strain Gauge of Electrodeposited Nickel

The properties of foil strain gauges made of a sheet of nickel foil electrodeposited in a sulphamate bath are studied by rotary bending tests at high temperatures. A nickel foil of 5 μm in thickness is obtained by tearing off the deposited nickel from a ground metal plate of stainless steel. A number of foil gauges of the same quality are made by dividing the nickel foil and they are stuck on the surface of the specimen with an adhesive of epoxy resin. Little effect of the adhesive layer on the proper stress of foil gauge is recognized, though the applicable test temperature is confined to the range of l80∼250°C. If the size of foil gauge is more than 1 mm2, the size effect of gauge on the proper stress is negligible. Using the foil gauges at 250°C, the peak stresses in grooved shafts under bending are measured and it is confirmed that the results are accurate enough.