OilDamper Material

• Command_Manual
  • Tcl Commands
  • Modeling_Commands
    • model
    • uniaxialMaterial
    • ndMaterial
    • frictionModel
    • section
    • geometricTransf
    • element
    • node
    • sp commands
      • fix
      • fixX
      • fixY
      • fixZ
    • mp commands
      • equalDOF
      • rigidDiaphragm
      • rigidLink
    • timeSeries
    • pattern
    • mass
    • block commands
      • block2D
      • block3D
    • region
    • rayleigh
  • Analysis Commands
    • constraints Command
    • numberer Command
    • system Command
    • test Command
    • algorithm Command
    • integrator Command
    • analysis Command
    • eigen Command
    • analyze Command
  • Output Commands
    • recorder
    • record
    • print
    • printA
    • logFile
    • RealTime_Output_Commands
  • Misc Commands
    • eleResponse Command
    • getTime Command
    • getEleTags Command
    • getNodeTags
    • loadConst Command
    • nodeCoord Command
    • nodeDisp Command
    • nodeVel Command
    • nodeAccel Command
    • nodeEigenvector Command
    • nodeBounds
    • print Command
    • remove Command
    • reset Command
    • testIter
    • testNorms
    • wipe Command
    • exit Command
  • DataBase Commands
    • Template:DataBaseCommandsMenu

---

This command is used to construct an OilDamper material, which simulates the hysteretic response of bilinear oil dampers with a valve relief. Two adaptive iterative algorithms have been implemented and validated to solve numerically the constitutive equations within a bilinear oil damper with a high-precision accuracy.

uniaxialMaterial OilDamper $matTag $K $Cd $alpha <$Fr $p> <$LGap> < $NM $RelTol $AbsTol $MaxHalf>

---

$matTag	integer tag identifying material
$K	Elastic stiffness of linear spring (to model the axial flexibility of an oil damper (brace and damper portion)
$Cd	Viscous parameter of oil damper
$alpha	Viscocity exponent
$Fr	Damper relief force (Damper property)
$p	Post-relief damping coefficient ratio (Damper property)
$LGap	gap length to simulate the gap length due to the pin tolerance
$NM	Employed adaptive numerical algorithm (default value NM = 1; 1 = Dormand-Prince54, 2=adaptive finite difference)
$RelTol	Tolerance for absolute relative error control of the adaptive iterative algorithm (default value 10^-6)
$AbsTol	Tolerance for absolute error control of adaptive iterative algorithm (default value 10^-6)
$MaxHalf	Maximum number of sub-step iterations within an integration step (default value 15)

---

Examples: |- |- |}

---

References:

[1]	Akcelyan, S., and Lignos, D.G. (2015), “Adaptive Numerical Method Algorithms for Nonlinear Viscous and Bilinear Oil Damper Models Under Random Vibrations”, ASCE Journal of Engineering Mechanics, (under review).
[2]	Oohara, K., and Kasai, K. (2002), “Time-History Analysis Models for Nonlinear Viscous Dampers”, Proc. Structural Engineers World Congress (SEWC), Yokohama, JAPAN, CD-ROM, T2-2-b-3 (in Japanese).
[3]	Kasai K, Oohara K. “Algorithm and Computer Code To Simulate Response of Nonlinear Viscous Damper” Passively Controlled Structure Symposium 2001, Yokohama, Japan (in Japanese).

Code Developed and Implemented by : Sarven Akcelyan & Prof. Dimitrios G. Lignos, (McGill University)