Super node Super nodes are placed at each end of the line. Loads, specified displacements, connection to support vessel and other boundary conditions may be applied at super nodes. Several lines may also be connected at the same super node. 1. Nodal Constraints Options: Free Fixed or Prescribed Slave Reference frame: Specify the frame of reference for the nodal coordinate specification. This can be a defined Reference frame or a SIMO body. When a SIMO body is selected, the node coordinates are given in the body coordinate system and follow the body. By default the GLOBAL coordinate system is used as reference frame. 1.1. Free 1.1.1. Initial position Options: Automatic initial position : Global position is found automatically by specifying two radial reference nodes, radial distance , vertical offset and a radial angle Global positions : Is specified by coordinates (Xg, Yg, Zg) 1.2. Fixed or Prescribed 1.2.1. Initial position Options: Automatic initial position : Global position is found automatically by specifying a reference line and direction w.r.t. the horizontal plane Global positions : Is specified by coordinates (Xg, Yg, Zg) 1.2.2. Fixed or Prescribed configuration Support vessel : Prescribed motion by specifying a support vessel. The motion is given by a RAO or by time series. Static global position : X, Y and Z position of vessel coordinate system referred in global system Specify the rotation of the node: Direction is the rotation in degrees from global X-axis to XREF-axis and Rotation Rotation is the specified rotation in degrees from stress free position to equilibrium position The rotation is about the local YREF-axis, as shown in the figure below. Direction = 0 means that the rotation is about the global Y-axis. If the line end is free to rotate about the local YREF-axis, Rotation is not used. Free rotation about the global Y-axis is obtained by setting the boundary condition for rotation about Y to free and Direction = 0. Figure 1. Definition of rotation axis YREF versus global coordinate system, X, Y. The super node is located in the origin Boundary conditions Specification of the boundary condition frame: Options Global system Vessel coordinate system Skew global coordinate system Skew vessel coordinate system If Skew coordinate system is specified, the system must be defined by specifying the x-axis in the skew system [Xx,Xy,Xz] and a reference vector [Xp,Yp,Zp]. Specification of the boundary condition for the node : Options are free/fixed for all degree of freedoms 1.3. Slave Specify the master node 1.3.1. Initial position Options: Automatic initial position : Global position is found automatically by specifying two radial reference nodes, radial distance , vertical offset amd a radial angle Global positions : Is specified by coordinates (Xg, Yg, Zg) A master node can not be slave of another master node. A slave node can only be slave of one master node. An arbitrary number of slave nodes can have the same master node. The number of DOFs at the slave node must not exceed the number of DOFs at the master node. Reference Frame Line