A shrink-fit process has been used to enhance the pressure carrying capacity of a cylinder. During the process, two concentric cylinders are shrunk fitted together to form a composite open-ended cylinder. Before the shrink-fit process, the inner cylinder has an inner radius of 50 mm and outer radius 75.025 mm, while the outer cylinder has an inner radius of 75 mm and outer radius of 150 mm. Both cylinders are made of steel with Young’s modulus E = 200 GPa, Poisson’s ratio  = 0.28, and yield stress Y = 600 MPa. Due to the shrink-fit process, an interface pressure (or shrink-fit pressure), Pc = 16.9 MPa, develops at the interface between the two cylinders

(b) After the shrink-fit process, the open-ended composite cylinder is to be used at an internal pressure Pi. What is the maximum internal pressure that can be applied to ensure simultaneous initiation of plastic yielding at the inner radii of the inner and outer cylinders? Assume Tresca yield criterion.