1. CONTACT - Contact point of roller type

Available for elastic contact surface description only.

um ii fig127
Figure 1. Example of a pipe support consisting of four rollers.

The local coordinate system \(\mathrm {(X_L,Y_L,Z_L)}\) of the elastic contact surface is indicated. \(\mathrm {X_L}\)-axis is pointing into the paper plane.

The contact point may contain several rollers.

The rollers are located in the \(\mathrm {Y_LZ_L}\)-plane of the element to which the contact point is attached. Besides the location, each roller is described by its length, which may be infinite, by its stiffness and dash pot damping. The location and orientation of a roller is defined by a point and an inclination angle referred in the local coordinate system of the contact surface element. A roller of finite length is shown in the figure below. The roller origin (starting point) is defined by the point \(\mathrm {(Y_R,Z_R)}\) and the inclination angle (ROTX) is defined by a clockwise rotation around the contact surface \(\mathrm {X_L}\)-axis.

Roller with finite length located in the local coordinate system of an element contributing to the elastic contact surface.

The \(\mathrm {X_L}\)-axis is pointing into the paper plane.

1.1. Data group identifier

NEW COMPonent CONTact

1.2. Component type identifier

CMPTYP-ID

  • CMPTYP-ID: character(8): Component type identifier

1.3. Number of rollers

NROLLS

  • NROLLS: integer: Number of rollers

The following 3 data groups (Location and orientation, Stiffness properties and Spring stiffness, Case 1 or 2) must be given in blocks for each of the NROLLS roller.

1.4. Location and orientation of roller axis

ROTX YR ZR RLENG

  • ROTX: real, default: 0: Direction of roller axis. (Clockwise around the \(\mathrm {X_L}\)-axis of the actual surface plane) \(\mathrm {[deg]}\)

  • YR: real, default: 0: Y-coordinate of roller origin \(\mathrm {[L]}\)

  • ZR: real, default: 0: Z-coordinate of roller origin \(\mathrm {[L]}\)

  • RLENG: real, default: 0: Length of roller \(\mathrm {[L]}\)

    • = 0 means infinite length

In case of infinite roller length, YR and ZR describe coordinates of an arbitrary point on the roller principal axis.

1.5. Stiffness properties classification and damping

IKS DAMP

  • IKS: integer: Stiffness code1

    • 1 : Constant spring compression stiffness

    • N : Table with N pairs of pressure force - displacements to be specified

      • N > 2

  • DAMP: real, default: 0: Dash pot damping coefficient \(\mathrm {[FT/L]}\)

1.6. Spring stiffness, Case 1 IKS = 1

STIFFR RADROL

  • STIFFR: real: Spring compression stiffness \(\mathrm {[F/L]}\)

  • RADROL: real: Radius of roller \(\mathrm {[L]}\)

The figure below describes the interpretation of contact force in case that IKS=1. The spring is active when the distance between the principal axis of the roller and the pipe is less than \(\mathrm {\Delta _0=RADROl+RTUBE}\). The external radius of the tube, RTUBE, is calculated from the external area of the cross section of the element in contact with the roller.

um ii fig130
Figure 2. Spring stiffness, IKS = 1

1.7. Spring stiffness, Case 2 IKS > 2

FS(1) ZS(1) ... FS(N) ZS(N)

  • FS(1): real < 0: Pressure force corresponding to compression ZS(1) \(\mathrm {[F]}\)

  • ZS(1): real: Spring compression \(\mathrm {[L]}\)

  • .

  • .

  • .

ZS(i) must be given in increasing order.

The figure below describes the interpretation of contact force in case that IKS>2. The specified stiffness characteristics is moved to account for the external radius of the tube, RTUBE. The external radius of the tube, RTUBE, is calculated from the external area of the cross section of the element in contact with the roller.

um ii fig131
Figure 3. Spring stiffness, IKS > 2

The three data groups Location and orientation, Stiffness properties and Spring stiffness, Case 1 or 2 are to be repeated NROLLS times.

2. Tensioner

Available for elastic contact surface description only.

The function of the tensioner is to grip and apply tension to the pipeline during the lay operation. In dynamic analysis the tensioner accounts for the pipeline pay out or pay in to prevent large oscillations in the pipeline tension. This is modelled as a dynamic boundary condition with respect to the applied axial force, eg. the applied load is T0 plus/minus a dead band range. Outside the dead band range the load is constant. The applied load which acts in the longitudinal direction of the tube, is formulated as a discrete element load. During static analysis the tensioner applies a constant load, T0, to the pipeline.