FEC complete detailed design and analysis for rectangular tank subject to internal explosion pressure.

The project had a number of unique constraints which led to our client requiring a rectangular tank. As a first pass, we completed elastic stress analysis and determined an allowable internal pressure using design by analysis methods. The design was optimised in terms of stiffener size, stiffener layout, plate thicknesses and weld details. During detailed design, a further question was raised about the ultimate failure pressure due to an explosion. Using an elastic plastic analysis with consideration of non-linear geometry and joint efficiencies, we were able to determine the failure pressure and associated internal design pressure based on a non-linear approach. Such an analysis takes advantage of the change in shape of flat plates under loading and reduces conservatism.

With the reduced conservatism, additional protections against failure need to be considered, but in many design scenarios, these can be managed effectively through the User Design Specification.