Also ensure your Abaqus element type matches the Nastran integration order, it must be equivalent to the CQUAD/CTRIA Nastran Mindlin to get equivalent results.
It's wise to test mesh resolution sensitivity before bouncing between solvers. A too-coarse mesh can result in hourglassing even under...
Sounds similar to the hollow stringer cavities on current composite commercial a/c shells (e.g. 787) which trap inflatable elastomer bladders between interior vacuum bags with exterior cauls. Scrap rates are very low. It is a good practice used with autoclave, but out of autoclave will be more...
Do you have a curing oven and a good vacuum source available? Cytec's PRISM EP2400 is a newer low-cost one-component worth considering, call Cytec or check http://www.cem-prism.com/.
Be very careful if you go with a wet hand layup with any resin as it will likely result in the worst quality...
