Membrane Property

Membrane property is a physical property assigned to surface elements. This property can be applied on linear triangle elements (TR3), parabolic triangle elements (TR6), linear quadrangle elements (QD4) and parabolic quadrangle elements (QD8).

A membrane property references a material assigned to the surface part and describes a thickness associated to this surface part. A membrane property is associative to the geometry this property points at.

Associated to this property, elements (linear or parabolic triangle, linear or parabolic quadrangle) have:

  • a plane stress state,
  • two degrees of freedom per node (both translations in the finite element plane),
  • no transversal stiffness,
  • longitudinal shearing,
  • tension / compression deformation.

The input and output characteristics are:

  • Input:

    • Material

    • Thickness

  • Output:

    • Stress

    • Strain

    • Point force vector 

    • Stress Von Mises 
    • Elastic energy
    • Elastic energy density 
    • Estimated error 

Those characteristics can be expressed at the given positions in the elements and in different axis systems:



Axis System 


Center of element 

Nodes of element 

Gauss point 









Point force vector




Stress Von Mises




Elastic energy





Elastic energy density 





Estimated error