This investigation is concerned primarily with the behavior of glass bottles under internal hydrostatic pressure. In their role as container or package for many and varied products, glass bottles must safely withstand the normal internal pressures which some products develop during processing and in use. Some highly carbonated bottled beverages may develop up to 125 pounds per square inc.. internal pressure in extremely -ot weather if allowed to reacn equilibrium; however* when chilled for serving, pressures do not exceed 40 to 45 pounds per square inch. Some bottled beers may develop as big as 90 pounds per square inch internal pressure in tie pasteurizing process at about l42*F and after pasteurization internal pressures of about 50 to 60 pounds per square inch may occur when bottled beer is subjected to extremely hot weatner. When chilled for serving, bottled beer does not exceed 15 to 20 pounds per square including internal pressure. This variation of pressure with temperature is related primarily to the change of solubility of CO2 in the liquid contents. Ciiampagne, similar sparkling wines, magnesia and other bottled products may develop internal pressures. While the magnitude of these pressures is not great it is nevertheless desirable to consider these glass bottles from the viewpoint of withstanding the maximum internal pressures which may reasonably be expected under actual conditions of use. The purpose of this investigation was to determine the general stress distribution in glass bottles caused by an applied internal pressure and the effect of certain elements of bcttle design on the stress distributions. The bottle designs selected for study were three One -Way beer bottles., namely the 12 oz. Export shape, 12 oz. Select shape and quart Select shape. These designs are typical and representative of good, commercial bottles which have been produced and used successfully as veil as extensively. Stress measurements and studies were directed to the bottle surfaces since glass almost invariably breaks from the surfaces* Also, since glass bottles break only in tension, primary interest was directed to the location, magnitude and orientation of the nmy-imim tensile stresses. Four principal methods of experimental stress analysis enployed in this study were: (l) Photoelastic studies of frozen stress models (Fosterite), (2) Brittle Model studies of glass bottles (Prototypes), (3) Electric Strain Gage measurements on glass bottles and (U) Stresscoat studies on glass bottles.
