# 4.2.4.3. Joint2D Element¶

This command is used to construct a two-dimensional beam-column-joint element object. The two dimensional beam-column joint is idealized as a parallelogram shaped shear panel with adjacent elements connected to its mid-points. The midpoints of the parallelogram are referred to as external nodes. These nodes are the only analysis components that connect the joint element to the surrounding structure.

element('Joint2D', eleTag, *eleNodes, <Mat1, Mat2, Mat3, Mat4>, MatC, LrgDspTag, <'-damage', DmgTag>, <'-damage', Dmg1 Dmg2 Dmg3 Dmg4 DmgC>)
 eleTag (int) unique element object tag eleNodes (list (int)) a list of five element nodes = [nd1,nd2,nd3,nd4,ndC]. ndC is the central node of beam-column joint. (the tag ndC is used to generate the internal node, thus, the node should not exist in the domain or be used by any other node) Mat1 (int) uniaxial material tag for interface rotational spring at node 1. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional) Mat2 (int) uniaxial material tag for interface rotational spring at node 2. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional) Mat3 (int) uniaxial material tag for interface rotational spring at node 3. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional) Mat4 (int) uniaxial material tag for interface rotational spring at node 4. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional) MatC (int) uniaxial material tag for rotational spring of the central node that describes shear panel behavior LrgDspTag (int) an integer indicating the flag for considering large deformations: * 0 - for small deformations and constant geometry * 1 - for large deformations and time varying geometry * 2 - for large deformations ,time varying geometry and length correction DmgTag (int) damage model tag Dmg1 (int) damage model tag for Mat1 Dmg2 (int) damage model tag for Mat2 Dmg3 (int) damage model tag for Mat3 Dmg4 (int) damage model tag for Mat4 DmgC (int) panel damage model tag