BilinearOilDamper Material: Difference between revisions
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| style="background:lime; color:black; width:800px" | '''uniaxialMaterial BilinearOilDamper $matTag $K $Cd | | style="background:lime; color:black; width:800px" | '''uniaxialMaterial BilinearOilDamper $matTag $K $Cd <$Fr $p> <$LGap> < $NM $RelTol $AbsTol $MaxHalf> ''' | ||
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| style="width:150px" | '''$matTag ''' || integer tag identifying material | | style="width:150px" | '''$matTag ''' || integer tag identifying material | ||
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| '''$K ''' || Elastic stiffness of linear spring | | '''$K ''' || Elastic stiffness of linear spring to model the axial flexibility of an oil damper (brace and damper portion) | ||
|- | |- | ||
| '''$Cd ''' || Viscous | | '''$Cd ''' || Viscous damper coefficient of an oil damper (before relief) | ||
|- | |- | ||
| | | '''$Fr ''' || Damper relief load (default=1.0, Damper property) | ||
|- | |- | ||
| '''$p ''' || Post-relief viscous damping coefficient ratio (default=1.0, linear oil damper) | |||
| '''$p ''' || Post-relief damping coefficient ratio ( | |||
|- | |- | ||
| '''$LGap ''' || gap length to simulate the gap length due to the pin tolerance | | '''$LGap ''' || gap length to simulate the gap length due to the pin tolerance (default=0.0: zero tolerance) | ||
|- | |- | ||
| '''$NM ''' || Employed adaptive numerical algorithm (default value NM = 1; 1 = Dormand-Prince54, 2=adaptive finite difference) | | '''$NM ''' || Employed adaptive numerical algorithm (default value NM = 1; 1 = Dormand-Prince54, 2=adaptive finite difference) | ||
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| '''$RelTol ''' || Tolerance for absolute relative error control of the adaptive iterative algorithm (default value 10^-6) | | '''$RelTol ''' || Tolerance for absolute relative error control of the adaptive iterative algorithm (default value 10^-6) | ||
|- | |- | ||
| '''$AbsTol ''' || Tolerance for absolute error control of adaptive iterative algorithm (default value 10^- | | '''$AbsTol ''' || Tolerance for absolute error control of adaptive iterative algorithm (default value 10^-10) | ||
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| '''$MaxHalf ''' || Maximum number of sub-step iterations within an integration step (default value 15) | | '''$MaxHalf ''' || Maximum number of sub-step iterations within an integration step (default value 15) | ||
Revision as of 12:16, 6 August 2015
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This command is used to construct a BilinearOilDamper 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 BilinearOilDamper $matTag $K $Cd <$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 damper coefficient of an oil damper (before relief) |
| $Fr | Damper relief load (default=1.0, Damper property) |
| $p | Post-relief viscous damping coefficient ratio (default=1.0, linear oil damper) |
| $LGap | gap length to simulate the gap length due to the pin tolerance (default=0.0: zero 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^-10) |
| $MaxHalf | Maximum number of sub-step iterations within an integration step (default value 15) |
Examples:
| 1. Input parameters: | |
| Assume a bilinear oil damper with axial stiffness K=200.0kN/mm, viscous damping coefficient C=6.0KN/(mm/s), relief load Fr=1000.0KN, p=0.1. | The input parameters for the material should be as follows: |
| uniaxialMaterial BilinearOilDamper 1 200.0 6.0 1000 0.1 | |
| Using these properties, Figure 1c shows the hysteretic response of this damper for sinusoidal displacement increments of 12, 24 and 36mm and a frequency f = 1.0Hz. Figures 1a-1d show the damper hysteresis with varying post-relief viscous damping coefficient ratio (p=1.0, 0.5, 0.1, 0.0). | |
| Assume a bilinear oil damper with axial stiffness K=200.0kN/mm, viscous damping coefficient C=6.0KN/(mm/s), relief load Fr=1000.0KN, p=0.1 and LGap = 0.5mm due to the pin tolerance at the damper ends. | The input parameters for the material should be as follows: |
| uniaxialMaterial BilinearOilDamper 1 200.0 6.0 1000 0.1 0.5 | |
| Using these properties, Figure 2c shows the hysteretic response of this damper for sinusoidal displacement increments of 0.5, 1 and 1.5mm and a frequency f = 1.0Hz. Figures 2a-2d show the damper hysteresis with varying gap length (LGap = 0.0, 0.2. 0.5. 1.0 mm) | |
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). |
Code Developed and Implemented by : Sarven Akcelyan & Prof. Dimitrios G. Lignos, (McGill University)