
element SimpleJoint2D eleTag? iNode? jNode? kNode? lNode? Panel? LrgDisp?

eleTag?  - an integer tag identifying the element in the domain 
iNode?   - an integer indicating the node at end 1 of the beam 
jNode?   - an integer indicating the node at end 2 of the beam 
kNode?   - an integer indicating the node at end 3 of the beam 
lNode?   - an integer indicating the node at end 4 of the beam 
Panel?   - an integer indicating uniaxial material tag for the shear panel
LrgDisp? - an integer for large deformations flag
newNode? - an integer indicating the tag of a new node added at center of joint
NewEle?  - an integer indicating the tag of the rotational element used in the joint for the shear panel.

SimpleJoint2D is a four-node element. It automatically creates a center node with a tag larger than 1000000.
SimpleJoint2D also defines special multi-point constraints to simulate a shear panel deformation and it can
be used along with 'Penalty', or 'Transformation' constraint handlers.

A uniaxial material model can be used as the rotational spring relating shear deformation to sheer 
equivalent moment. for LrgDisp flag, zero indicates that the element will use a constant constraint matrix, 
calculated based on initial configuration. A non-zero value indicates that the MP constraint matrix will be 
time varying. Value 1 for time varying 

constraint that updates for each load step, without length correction. Value 2 for time varying constraint 
with length correction.

The valid queries to a SimpleJoint2D element when creating an ElementRecorder are 'internalNode',
 'deformation', 'moment', or 'material ...'. 	   

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Example: element SimpleJoint2D 2 1 2 3 4 1 0 22 24

Constructs a SimpleJoint2D element with tag 2 that is connected to nodes 1 , 2, 3 and 4.
The element uses the uniaxialmaterial objects with tag 1, with constant constraint matrix 
(no large deformation). The new node added to the domain at the center of the joint will be 
numbered 24 and the new rotational element added to model shear in the joint will be 24.
