cls1268
Aerospace
- Aug 25, 2004
- 1
Hi all, I would like to check concerning the simulation of pressure bulkheads subjected to pressurization during flight.
The pressure bulkhead of interest is a flat one, and under pressure is similar to a plate under normal loading.
The modification involved in my case happened to be a small area bounded by stiffeners, near the boundary of the pressure bulkhead.
As its a small location, I'm trying to create a localized finite element model and perform a pre-mod and post-mod analysis to understand the impact of the modification.
The pressure bulkhead has a diameter of approx. 70" and thickness of 0.125", with a grid-like stiffeners. The area of modification measures approximately 7" x 8" at approximately 11 o'clock position, near the boundary of the bulkhead, which is located within stiffening members.
I am thinking of simulating it by creating a 7" x 8" rectangular plate, meshing it using FEMAP and solving it in NASTRAN. Elements used will be CQUAD4/ CTRIA3 (A couple of cutouts measuring diameter 1" and 3.5" is found in this area as well). Boundary condition wise, I am thinking of applying a pinned all round and applying a 1 psi on the surface. However another likley BC is to apply tension on one of the edges, and pinned on 3 edges. The latter load case takes into account the membrane action expected when a relatively thin plate is loaded under normal loads.
As I don't have the actual loads, I plan to perform a pre and post modification analysis to determine the impact of the modification as a means of substantiation.
I would like to seek advice from the experts here if this method of simulation is meaningful.
Thanks and have a nice day.
CLS
The pressure bulkhead of interest is a flat one, and under pressure is similar to a plate under normal loading.
The modification involved in my case happened to be a small area bounded by stiffeners, near the boundary of the pressure bulkhead.
As its a small location, I'm trying to create a localized finite element model and perform a pre-mod and post-mod analysis to understand the impact of the modification.
The pressure bulkhead has a diameter of approx. 70" and thickness of 0.125", with a grid-like stiffeners. The area of modification measures approximately 7" x 8" at approximately 11 o'clock position, near the boundary of the bulkhead, which is located within stiffening members.
I am thinking of simulating it by creating a 7" x 8" rectangular plate, meshing it using FEMAP and solving it in NASTRAN. Elements used will be CQUAD4/ CTRIA3 (A couple of cutouts measuring diameter 1" and 3.5" is found in this area as well). Boundary condition wise, I am thinking of applying a pinned all round and applying a 1 psi on the surface. However another likley BC is to apply tension on one of the edges, and pinned on 3 edges. The latter load case takes into account the membrane action expected when a relatively thin plate is loaded under normal loads.
As I don't have the actual loads, I plan to perform a pre and post modification analysis to determine the impact of the modification as a means of substantiation.
I would like to seek advice from the experts here if this method of simulation is meaningful.
Thanks and have a nice day.
CLS