Selecting the optimum loading conditions for glasses and light-sensitive glasses when testing them in compression

Abstract

1. In testing testpieces of glasses and light-sensitive glasses in compression with smooth metal bearings the high contact stresses facilitate premature failure of the testipieces and the production of reduced strength characteristics with large dispersion values. 2. The method of cementing the ends of the testpices in the sockets of the yoke using self-hardening compositions is an effective method of combatting the high-contact stresses 3. The maximum strengths under otherwise equal conditions are achieved when using an epoxy cement heat cured at a temperature of 150°C for 7 h, and containing the components, wt. %: ED-6 epoxy resin 7.5; dibutylphthalate 14.8; and polyethylenepolyamine 11.2. 4. When the ends of testpieces made from glasses and ligh-sensitive glasses are cemented into the sockets of the metal yokes to a depth of 0.5 to 0.8 and when the length of the free part is 1.3–2.0 the diameter or side of the base the maximum strengths are achieved, almot independent of the contact stresses. 5. From the condition of providing maximum load capacity and reliability the preferred cross section of smooth structural highly stressed elements of glasses and light-sensitive glasses, operating under compression, is that of a cricle. 6. The load capacity and reliability of compressed rods of glasses and light-sensitive glasses may be raised substatially both on account of increasing the depth of cementing the ends in the yoke and also due to diminution of the working length.