stress analysis question (rocket science)?

Question

At work I do stress analysis on launch vehicles. Our loads and dynamics group gives us loads (in pounds) called "Peq" or P_equivalent at various "stations" or vertical coordinates of the rocket. Most rockets, including ours, consist of a stack of lightweight hollow cylindrical structures all bolted together. The loads in these structures increase as we go down the rocket (obviously because the lower you go the more weight the structures carry along with the aero loads and pressures. My question is, what do they mean by Peq? How do they calculate these loads? I've always been curious. The loads group just keeps feeding us these numbers we plug into our models but have no idea where they come from. If anyone who does the same type of work as me could respond, that would be awesome. Thanks!

Answer 1

I do not work with rockets. However, remember from physics, F = ma? It takes force to accelerate the sections above that can be calculated from the formula.

I am sure that they know approximate drag coefficients and use those to calculate the aerodynamic forces.

What they are calling "Peq" is the sum of loads from acceleration, aerodynamics, and gravity. They simply give you the sum because for your task it is not necessary to know how much of the total comes from each of the 3 sources.

Answer 2

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