ILIR Task of Mechanical Gauge for Peak Chamber Pressure Measurements in Large Caliber Guns (Catastrophic Failure Backup Gauge).
Partial rept. 13 Nov 84-30 Sep 85,
ARMY COMBAT SYSTEMS TEST ACTIVITY (PROV) ABERDEEN PROVING GROUND MD
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A new pressure gauge based on the shearing of circular plugs in metals is being investigated for use in large caliber guns when chamber pressures may exceed 120 kpsi. The proposed shear gauge can in principle be made to measure peak chamber pressures up to and greater than 300 kpsi. A prototype model of the gauge has been designed and fabricated, but not yet tested. The design of the shear gauge involves the shearing of a uniformly loaded circular plate at its circumferential support. Stresses due to bending and shear were analyzed to choose the proper hole radius-to-thickness ratio that ensures a shearing and not a bending failure of the plate. A critical radius-to-thickness ratio was derived. The advantages of the shear gauge are a small size, the lack of temperature and pressure limitations, the estimated low manufacturing cost, and the absence of any moving parts. The disadvantage of the shear gauge is the discrete nature of the measurement, which gives not a precise reading but an upper and lower limit within a given tolerance. Keywords Pressure gauge Chamber pressure measurements Catastrophic failure backup gauge Mechanical pressure gauge.