ShellMITC4 stress calculation
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ShellMITC4 stress calculation
Hi everyone, I am using the ShellMITC4 shell element , the stress result of the element including 32 parameters, which is the (F11, F22, F12, M11, M22, M13, V12, V13) at the four gauss integration points, I want to know how to calculate the stresses (S11, S22, S33, S12, S13) at the gauss integration points.
Can anyone help me? Thank you !
Can anyone help me? Thank you !
Re: ShellMITC4 stress calculation
It depends on which section model you're using. If it's ElasticMembranePlateSection, then you can't get the stress directly. If it's PlateFiber, then you can use a recorder with something like "recorder Element .... material 1 fiber 3 stress"
The number after material should be from 1 to 4 (Gauss points)
The number after fiber should be from 1 to 5 (there are five fibers through the thickness of the PlateFiber section)
The number after material should be from 1 to 4 (Gauss points)
The number after fiber should be from 1 to 5 (there are five fibers through the thickness of the PlateFiber section)
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 Posts: 43
 Joined: Sat Oct 08, 2011 6:28 am
Re: ShellMITC4 stress calculation
Hello,
I read here that one can use:
to get results in this order:
If I use ShellMITC4 and PlateFiber, like this:
I have all results as zero for: since "material 1" is misleading I suppose...
I have 24 results (6 forces/moments by 4 GPs) for:
I cannot still obtain the generalized shell forces Nxx, Nyy, Nxy, Mxx, Myy, Mxy, Vxz, Vyz.
How the recorder should be written in order to get such forces per unit lenght? They should be 8 x 4GPs.
To clarify, I'm not looking for singlefiber stresses. Thanks in advance
I read here that one can use:
Code: Select all
recorder Element file ele1gp1forces.out time ele 1 material 1 forces
Code: Select all
[Time Nxx, Nyy, Nxy, Mxx, Myy, Mxy, Vxz, Vyz]
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nDMaterial ElasticIsotropic 3 210000 0.3
nDMaterial PlateFiber 2 3
section PlateFiber 1 2 0.01
# shell elements
element ShellMITC4 1 10001 10145 10147 10146 1
...
Code: Select all
recorder Element file ele1gp1forces.out time ele 1 material 1 forces
I have 24 results (6 forces/moments by 4 GPs) for:
Code: Select all
recorder Element file ele1gp1forces.out time ele 1 forces
How the recorder should be written in order to get such forces per unit lenght? They should be 8 x 4GPs.
To clarify, I'm not looking for singlefiber stresses. Thanks in advance

 Posts: 43
 Joined: Sat Oct 08, 2011 6:28 am
Re: ShellMITC4 stress calculation
I think I found the point  theElement>strain was always zero, due to the fact that
does not set any trial strain on the element.
I used this because at this stage my model is linear, anyway I turned into and now I have forces.
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algorithm Linear
I used this because at this stage my model is linear, anyway I turned into
Code: Select all
algorithm Newton
Re: ShellMITC4 stress calculation
Yeah, even with a linear model, it's still always a good idea to use the Newton algorithm.
Same kind of thing happens with member loads on forcebased beamcolumn elements where you need the second iteration for the loads to have an effect.
Same kind of thing happens with member loads on forcebased beamcolumn elements where you need the second iteration for the loads to have an effect.
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