====== MEM2D ======
Plane membrane in in generalized plane state
===== Description =====
Element for mechanical analysis with plane shells in generalized plane state ([[:prepro#remark_on_ntana|NTANA]]=7, IANA=5). \\
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Plane membrane element with 2 nodes; linear interpolation of displacements. The thickness is actualized. \\
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The numerical integration is done using 1 or 2 Gauss points. Two points may be necessary to take into account phenomena linked to the generalized plane state correctly. \\
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The available material laws are laws [[laws:hilsh|HILSH]] and [[laws:ilysh|ILYSH]]. \\
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Initial stresses are permitted. \\
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Up to 5 elements of contact/load can be coupled to this element (the coupling consists in the remoteness, equal to half the thickness, of the surface of contact with respect to the mean axis). 
{{  :elements:mem2d.png?500  |}}
Type: 40 \\
Implemented by: L. Grisard, 1991
==== Files ====
Prepro: MEM2DA.F \\
Lagamine: MEM2DB.F
===== Input file =====

^Title (A5)^^
|Title|"MEM2D" in the first 5 columns|
^Control data (I5)^^
|NELEM|Number of membrane elements|
^Definition of the elements (3I5/3G10.0)^^
|NPI|Number of integration points (Default value =1)|
|LMATE|Material law|
|NELMC|Number of contact elements (loading associated to this membrane element (0 ≤ NELMC ≤ 5))|
|THICK|Thickness e of the membrane|
|SIG1|Initial normal stress $\sigma_x$ in the local direction x|
|SIG2|Initial normal stress $\sigma_z$ in the local direction z|
^Definition of the contact/loading elements (3I5) - Only if NELMC ≠ 0 (repeat NELMC times)^^
|NPICNT|Number of integration points for the contact/loading elements (NPICNT ∈ [1, 10])|
|MATCNT|Number of the contact/loading law|
|IFOND|Number of the foundation (only if contact)|
^Nodes of the membrane element (2I5)^^
|NODES(I) \\ I=1,2|Nodes of the element|