Roller Contact

A roller contact point is part of an Elastic Contact Surface and models the interaction between a pipe and a physical roller support (e.g. on a lay barge stinger).

The roller contact is described with 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

Coordinate system
Each roller is defined in the local coordinate system \((X_L, Y_L, Z_L)\) of the contact surface element. The \(X_L\)-axis runs along the pipe; rollers are located in the \(Y_LZ_L\)-plane.

Location and orientation

A roller is positioned by:

  • Its origin point \((Y_R, Z_R)\) in the local system

  • An inclination angle ROTX (clockwise rotation around \(X_L\))

  • A length RLENG — set to 0 for infinite length

A roller of finite length is shown in Figure 1. The roller origin (starting point) is defined by the point (YR, ZR) and the inclination angle (ROTX) is defined by a clockwise rotation around the contact surface XL-axis, see Figure 2.

Contact force
When the pipe touches a roller, a contact force acts normal to both pipe and roller, modelled as a bi-linear or non-linear spring with bi-linear dash pot damping.

See Roller for spring stiffness and damping properties.

Multiple rollers
A single contact point can contain several rollers (e.g. four rollers arranged around the pipe cross-section).

Contact point definition available for elastic contact surface description only.

1. Parameters

1.1. Location and orientation of the contained roller(s)

This is repeated for each roller

  • Name : Name of roller, see Roller specification.

  • Direction: Direction of roller axis — clockwise rotation around the contact surface \((X_L)\)-axis

  • Y-coordinate: Y-coordinate of roller origin in local contact surface system

  • Z-coordinate: Z-coordinate of roller origin in local contact surface system

  • Length: Length of roller. Set to 0 for infinite length

RollerContact
Figure 1. Example of roller of finite length. The roller origin is defined by the point (YR,ZR) . The inclination angle (RotX) is defined by a clockwise rotation around the contact surface x-axis
Roller
Figure 2. Example of a pipe support consisting of four rollers. The local coordinates system of the elastic coordinate system is indicated. The x-axis is pointing into the paper plane.