FEDEASLab

Geometry > kg_3dFrm

kg_3dFrm

Purpose

geometric stiffness matrix for 2-node 3d frame element different options

Synopsis

kg = kg_3dFrm (option,xyz,GeomData,u,q,ElLoad)

Description

KG_3dFRM geometric stiffness matrix for 2-node 3d frame element different options
  KG = KG_3dFRM (OPTION,XYZ,GEOMDATA,U,Q,ELLOAD)
  the function determines the geometric stiffness matrix KG of a 2-node element with end
  coordinates in array XYZ (node i corresponds to first column and node j to second);
  the geometric stiffness matrix depends on the node displacement values in array U (ndfx2)
  in the global reference system and on the basic force vector Q;
  OPTION is a character variable with one of three values:
  'linear','PDelta' and 'corotational' for linear, P-Delta and corotational geometry, resp.

Cross-Reference Information

This function calls:

  • Coro3dKinematics determine deformations and kinematic transformation matrices
  • ElmLenOr element length and x-axis orientation (direction cosines)
  • Rot2q convert normalized rotation vector to quaternion representation
  • spin determine the spin tensor of a vector
This function is called by:
  • Inel3dFrm_wLHNMYS 3d frame element with elastic-linear hardening plastic axial-flexure hinges
  • Dinel3dFrm_EBwDF Euler-Bernoulli 3d-frame element with distributed inelasticity (displacement formulation)
  • Dinel3dFrm_EBwFF 3d-frame element with distributed inelasticity (iterative force formulation)
  • LE3dFrm 3d linear frame element under linear or nonlinear geometry