12.2 Consider the pressure hull of Examples 7.5 and 12.1. For each material listed in the following table, calculate the minimum mass and wall thickness of the pressure hull for

both failure mechanisms (i.e, external-pressure buckling and yield/compressive fracture) at the design pressure Hence determine the limiting failure mechanism for each material. (Hint: This is the failure mechanism which gives the larger of the two values of t. What is the optimum material for the pressure hull? What are the mass, wall thickness, and limiting failure mechanism of the optimum pressure hull?