Manganin Gage Pressure Measurements under Conditions Where Gage Deformation Occurs

摘要

It is sometimes desirable to use manganin piezo-resistive pressure gages under conditions where gage deformation occurs. In such circumstances, the pressure can be measured only if the strain on the gage is measured independently and if the strain coefficient of the gage is known. We have experimentally determined the strain coefficient of manganin gages as a function of strain at a range of pressures and strain rates. For small strains (less than 0.1 percent), the strain coefficient is about 0.67. As strain occurs, the strain coefficient increases to a value of about 2. In cantilever beam tests, with no pressure on the gage, the transition occurs slowly, and the strain coefficient reaches the value of 2 at about 2 percent strain. In a test where pressure and strain are applied simultaneously, the transition is more rapid and the strain coefficient attains a value of about 1.8 at 0.5 percent strain. (Author)