Compute the minimum value of plane strain fracture toughness required of a material such that a leak-before-break criterion is satisfied for a cylindrical pressure vessel similar to that shown below. The vessel radius and wall thickness values are 250 mm and 10.5 mm, respectively. Assume a value of 1.5 for the factor of safety, a shape factor of 2.25 and use the internal tank pressure shown in that table below for instructor. Instructor LTC Gash Dr. Freidenberg LTC Moody MAJ Milliam MAJ Arnold MAJ Linford Internal Pressure 700 kPa 725 kPa 750 kPa 775 kPa 700 kPa 725 kPa Note on Leak-before-break: Using principles of fracture mechanics, allowance is made for the growth of the crack through the thickness of the vessel wall prior to rapid propagation and brittle fracture. Thus, the crack will completely penetrate the wall without catastrophic failure, allowing for its detection by the leaking of pressurized fluid.