An Investigation into the Causes of Ceramic Cracking in the Mark 11Source (400Series).

摘要

In summary, this investigation has shown that 10% of the Edo-Western ceramics used in the Bendix source are weak, that is, they fail at hoop tensile stresses of 5000 psi or less, and a few fail at stresses as low as 1000 psi. It was found that a proof test of the elements of 6000 psi would eliminate the weak ceramics without damaging the survivors. All in-service failures (from environmental testing or handling) were found to occur in ceramic elements which contained large flaws or other defects. The strength of these was calculated to be 6000 psi or less, and the strength distribution was significantly different from normal Edo-Western ceramics. The fracture of the in-service failed elements was due to hoop tension which arises from the action of the neoprene spacer under axial compression. All service failures occurred either at solder joints or from edge defects at the non-bonded side of the element.