Fracture mechanics of aluminum beverage containers - An experimental investigation

The fracture mechanics behavior of 355 mi aluminum beverage containers (both 0.0039" and 0.0044" minimum wall thicknesses) was investigated by two general types of experiments. First, cracked center panel thinwall specimens were cut such that the crack was either parallel or perpendicular to the container axis at the mid-height position. These two specimen orientations were repeated at 0, 45, and 90 degrees to the roll direction, making for a total of six different specimen orientations. These six orientations yielded average fracture toughness values ranging from 16.0 to 19.1 ksi root in. The lowest fracture toughness orientation from the center cracked panel tests was selected for the second experiment. This involved containers machined with an external crack of known length and depth, filled with 355 mi of water, and pressurized to failure. At a constant crack depth, an increasing crack length gave a decreasing failure pressure. For a constant crack length, an increasing crack depth gave a decreasing failure pressure. In both cases, a transition from a leaking to a rupturing failure is seen, with longer and shallower cracks resulting in ruptures. These results are compared to accepted leak-before-break fracture mechanics theory.