Are there some exmples about membrane large deformation simulation input file?

[teken]

I want to simulate membrane large deformation using FEAP. But I don't know how to write the input about this kind of problems.

[teken]

the following is some of my input file:
MATE 1
  MEMBrane
    ELAStic ISOT 588000000.0 0.4
    THICk membrane 0.00025
    DENSity mass 270.0
    FINIte
。。。。。。。。。。。。。
BATCh
DT,,0.0000001
TRAN,,0.2 0.3
  LOOP,time,100
    TIME
    LOOP,newton,50
      UTAN,,1
    NEXT iter
  NEXT
save
END
stop

Are there some mistakes in the input?

[teken]

I don't know whether FEAP can deal with the problem of membrane with large deformation caused by follower pressure.

[FEAP_Admin]

Attached is a simple example. 

To change from follower to dead loads simply uncomment/comment out the line with follower on it on the pressure element property specifications.

[teken]

thanks for your reply, i will try this example.

[teken]

Sorry, i still have some questions about membrane inflation. My FEAP's version is 7.5. I want to know whether it can solve the large deformation problems of membrane inflation with follower pressure.

[FEAP_Admin]

Not sure if there is one in 7.5.  Take a look in the directory elements/shells and see if there is a membrane element present.

[teken]

YES, there are membrane element file.

[teken]

I found that in your input file, boungaries are setted all restrictted at all directions. I want set boundary restrict just at z direction. Can it work well with this boundary condition.

[FEAP_Admin]

As long as your specify enough boundary conditions to have a well-posed boundary value problem (i.e. no rigid body modes) then it will work just fine.

[Xingyuan]

This information is also helpful for me. Thanks teken and the FEAP_Admin.

But I have a question concerning also this membrane problem: If I want the load to be a time dependent function e.g. P=Pmax*sin(2*pi*time). How can I modify the input file?

[FEAP_Admin]

You should have a look at the Examples manual to first understand dynamic problems and then take a look at the User manual with particular attention to the description of the elements and their options as well as the sections on transient loads.

[teken]

I want to know if feap can handle the problem about large deformation in airbag inflation or not.

[Prof. R.L. Taylor]

The membrane should work in a dynamic problem.   The ver7.5 should do it but does not have axisymmetric capability.  It can do a plane and 3-d.  Do you have a mesh you want to test?  If so please post and we can look more at it. 

[teken]

I just do a test of an example in the paper "A GEOMETRICALLY NONLINEAR FINITE ELEMENT ANALYSIS OF WRINKLED MEMBRANE SURFACES BY A NO-COMPRESSION MATERIAL MODEL". But i found the result is not correct.