engineering for deflection

Plastic Pressure Accumulator

On the left is a prototype pressure accumulator. The parts are cracked at the junction of the ribs to the flange around the perimeter. How do you fix this?

The counter-intuitive answer: remove the ribs. This will eliminate the stress concentrations at the perimeter. It will also reduce the overall stiffness of the top structure. During pressurization, the entire top surface can then expand in a consistent manner, with uniform stress distribution.