VIBRO_5_Porous_materials-ACTRAN多孔材料模型介绍
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Theory Poro-elastic Materials ACTRAN Training –VIBRO
Poro-elastic material in a car
Used for discretizing porous media, i.e.
the fluid and solid phases in one
element.
Based on Biot Model: skeleton, fluid,
solid/fluid interaction
u-p formulation : u (solid displacement)
and p (fluid pressure within the pores)
Picture courtesy of Rieter Automotive
Porous materials are used by different porous models (rigid, UP, lumped, Delany-
Bazley)
Material properties are divided in: Fluid properties BEGIN MATERIAL Id
POROUS
FLUID_DENSITY value
FLUID_BULK_MODULUS value VISCOSITY value
Fluid-skeleton properties
Micromodel parameters
Elastic parameters
All values can be complex
THERMAL_CONDUCTIVITY value CP value
CV value
POROSITY value
FLOW_RESISTIVITY value
BIOT_FACTOR value TORTUOSITY value
VISCOUS_LENGTH value THERMAL_LENGTH value SOLID_DENSITY value
YOUNG_MODULUS value POISSON_RATIO value
END MATERIAL Id
Syntax in the ACTRAN input file:
Definition in ACTRAN/VI:
BEGIN MATERIAL Id POROUS
FLUID_DENSITY value
FLUID_BULK_MODULUS value POROSITY value
FLOW_RESISTIVITY value BIOT_FACTOR value Fluid properties
Fluid-skeleton
TORTUOSITY value VISCOSITY value
THERMAL_CONDUCTIVITY value CP value CV value
VISCOUS_LENGTH value THERMAL_LENGTH value SOLID_DENSITY value YOUNG_MODULUS value POISSON_RATIO value END MATERIAL Id
properties
Micromodel parameters
Elastic parameters
The RIGID_POROUS component is used for
discretizing a porous medium when the material skeleton can be assumed as rigid.
Points to a valid acoustic POROUS material
Supported topologies
(no elastic properties needed)
Unknowns: fluid pressure (1 dof/node)
(skeleton displacement is assumed rigid, hence u=0)
Based on a reduced Biot’s model
Syntax in the ACTRAN input file: Definition in ACTRAN/VI:
BEGIN COMPONENT Id
RIGID_POROUS
MATERIAL value
POWER_EVALUATION value
END COMPONENT Id
Porous Material Properties required:
FLUID_DENSITY
FLUID_BULK_MODULUS
POROSITY
FLOW_RESISTIVITY
BIOT_FACTOR
TORTUOSITY
VISCOSITY
THERMAL_CONDUCTIVITY
[VISCOUS_LENGTH]
[THERMAL_LENGTH]
The LUMPED_POROUS component is used
for discretizing porous medium when the material skeleton can be assumed as extremely soft (E=0)
Supported topologies
Points to a valid acoustic POROUS material
(solid density is needed for inertia)
Unknowns: fluid pressure (1 dof/node)
(skeleton displacement is assumed soft, hence u=w)
Based on a reduced Biot’s model