Quad9 class

Parent class

Class doc

Patch test for the finite deformation 9-node quadrilateral

Full bi-quadratic interpolation

       1
    x     y
x^2   x*y   y^2
  x^2*y x*y^2
    x^2*y^2
class femedu.elements.finite.Quad9.Quad9(node0, node1, node2, node3, node4, node5, node6, node7, node8, material, label=None)

class: representing a plane 9-node quadrilateral

This element works as 2D plate, loaded in-plane, and as a 3D membrane element.

  • For 2D plate behavior, define nodes as two-dimensional nodes

  • For 3D membrane behavior, define nodes as three-dimensional nodes

computeSurfaceLoads()

compute surface loads using faces

This method should be called during updateState() by every element supporting surface loads

Nodes are mapped between the element and each Face2D as follows

Mapping element node IDs to face node IDs

Face ID

Face nodes (0,1,2)

0

(0,4,1)

0

(1,5,2)

0

(2,6,3)

0

(3,7,0)
mapGaussPoints(var)

Initiate mapping of Gauss-point values to nodes. This method is an internal method and should not be called by the user. Calling that method explicitly will cause faulty nodal values.

Parameters:

var – variable code for a variable to be mapped from Gauss-points to nodes

resetLoads()

default implementation for resetting element loads.

setSurfaceLoad(face, pn, ps=0)

face ID

nodes defining that face

0

node 0 to node 4 to node 1

1

node 1 to node 5 to node 2

2

node 2 to node 6 to node 3

3

node 3 to node 7 to node 0
Parameters:

  • face – face ID for the laoded face

  • pn – magnitude of distributed normal load per area. Tension on a surface is positive.

  • ps – magnitude of distributed shear load per area. Positive direction is defined as shown in the above table.

updateState()