Modeling a FRP shell with internal pressure in an assembly and FEA
Modeling a FRP shell with internal pressure in an assembly and FEA
(OP)
This a post I have on the Cosmos forum but I haven;t gotten any repsonse so I thought I'd try here -
I have an FRP ( fiberglass ) form that is being held by several external bracing "clamps". Basically the form is a W shape but with the the W vertices flat instead of pointed. The 'clamps" are aluminum extrusions along length-wise being rigidly held in place by bolts.There is an internal pressue of 30 psi pushing out of the form and the clamps are there to keep it from deforming to the point of failure, i.e. bubbling "too much" ( more than 1/2" inch ) or outright cracking.
Should I be modeling the FRP W as a shell? it is approx 3/16" thick. And if it is a shell what faces ( inside or out ) do I apply pressure?
I looked up some "numbers" for FRP to try and guesstimate material properties for it but am open to further input.
Thanks!!!!!!!!!!!!!!!!!!!!!!!
I have an FRP ( fiberglass ) form that is being held by several external bracing "clamps". Basically the form is a W shape but with the the W vertices flat instead of pointed. The 'clamps" are aluminum extrusions along length-wise being rigidly held in place by bolts.There is an internal pressue of 30 psi pushing out of the form and the clamps are there to keep it from deforming to the point of failure, i.e. bubbling "too much" ( more than 1/2" inch ) or outright cracking.
Should I be modeling the FRP W as a shell? it is approx 3/16" thick. And if it is a shell what faces ( inside or out ) do I apply pressure?
I looked up some "numbers" for FRP to try and guesstimate material properties for it but am open to further input.
Thanks!!!!!!!!!!!!!!!!!!!!!!!






RE: Modeling a FRP shell with internal pressure in an assembly and FEA
I am assuming that your pressure question is do you use the inside or outside face of the pressure vessel. Typically I have used a midplane however for large aspect ratio parts it really doesn't matter.
Fiberglass properties vary significantly depending on the layup, glass, resin, processing, fiber volume ratio, procity...
I hope this helps.
Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/
RE: Modeling a FRP shell with internal pressure in an assembly and FEA
TOP
CSWP, BSSE
www.engtran.com www.niswug.org
www.linkedin.com/in/engineeringtransport
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RE: Modeling a FRP shell with internal pressure in an assembly and FEA
I know this is not the correct forum for FEA but no one replied on the Cosmos/Simulation forum.
RE: Modeling a FRP shell with internal pressure in an assembly and FEA
I made a comment that I don't see in this thread regarding FRP. Basically anything plastic or composite is so affected by process and choice of materials that it just doesn't make sense to do much of anything without some decent test data. And unlike metals, both humidity and temperature are huge factors which make a general rule pretty unsafe and difficult to do.
TOP
CSWP, BSSE
www.engtran.com www.niswug.org
www.linkedin.com/in/engineeringtransport
"Node news is good news."
RE: Modeling a FRP shell with internal pressure in an assembly and FEA
Another issue - when i run Comosworks ( 2008 ) on assemblies ( more than one component ) many times ( not always ) some of the components disappear during the analysis. I can drag pointer over them and the outline shows, but they and any graphical stress, deformation,etc. are missing.
Any thoughts?