1. Tubular contact component

This component is available for elastic contact surface description only.

1.1. Data group identifier, one input line

NEW COMponent TUBUlar contact

1.2. Component type number

CMPTYP-ID

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

1.3. Specification of contact force characteristics

RCONT CHDIR IKS DAMP STIFFR FRICST FRICDY CHAXI CHROT VELLIM

  • CONT: real: Contact radius \(\mathrm {[L]}\)

  • CHDIR: character: Contact direction: INWARDS or OUTWARDS

  • IKS: integer: Stiffness code for radial contact force

    • = 1 Constant contact compression stiffness

    • = N Table with N pairs of contact force - displacement to be specified

  • RELDAM: real: = Desired relative damping level at estimated eigen period in the pipe, pipe and contact spring system (see below) \(\mathrm {[1]}\). Damping is only applied in the radial direction. Not used in static analysis.

  • DAMP: real: Dash pot damping coefficient \(\mathrm {[FT/L]}\). Damping is only applied in the radial direction. Not used in static analysis.

  • STIFFR: real: Spring stiffness associated with static friction coefficient FRICST, \(\mathrm {[F/L]}\). The spring stiffness is applied in the ring and axial directions until the spring force exceeds the static friction force. Not used in static analysis. Dummy if CHAXI = OFF.

  • FRICST: real: Static friction coefficient \(\mathrm {[1]}\). Not used in static analysis. Dummy if CHAXI = OFF.

  • FRICDY: real: Dynamic sliding friction coefficient \(\mathrm {[1]}\). FRICDY <= FRICST. Not used in static analysis. Dummy if CHAXI = OFF.

  • CHAXI: character: Control parameter for axial sliding friction

    • = ON

    • = OFF

  • CHROT: character: Control parameter for friction caused by rotation

    • = ON Requires CHAXI=ON

    • = OFF

  • VELLIM: real: Velocity limit for determining that sliding has stopped \(\mathrm {[L/T]}\). If the relative sliding velocity between the pipes falls below VELLIM, the spring stiffness STFFR is applied. Should be small, but not zero. Not used in static analysis. Dummy if CHAXI = OFF.

Based on specified damping level the stiffness proportional damping coefficient is calculated by

\(\mathrm {a_2=RELDAM\times 2\times \sqrt\frac{(AMS\times L)_M+(AMS\times L)_S}{STIFF}}\)

where \(\mathrm {(AMS\times L)_M}\) and \(\mathrm {(AMS\times L)_S}\) are total structural element mass of the master pipe and the slave pipe respectively and \(\mathrm {STIFF}\) is contact spring sitffness.

1.4. Contact spring stiffness; IKS = 1

STIFF

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

1.5. Contact spring stiffness; IKS > 1

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

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

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

ZS(i) must be given in increasing order