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QA SYSTEM MODELS-INTERNSHIP (10th to 17th August 2020)

Raghuvamshi C L

8/17/2020

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Agenda

  • Introduction
  • Commands used for this week models
    • *FUNCTION
    • *INITIAL_DAMAGE_RANDOM
    • *INITIAL_DAMAGE_SURFACE_RANDOM
    • *INITIAL_MATERIAL_DIRECTION
    • *INITIAL_MATERIAL_DIRECTION_WRAP
    • *MAT_ORTHOTROPIC
    • *MERGE
    • *MERGE_DUPLICATE_NODES
    • *MERGE_FAILURE_COHESIVE
    • *TRANSFORM_MESH_CARTESIAN
    • *TRANSFORM_MESH_CYLINDRICAL
    • Conclusion

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Objective

  • To understand and analyze the different commands
  • To standardise the format of the models that used in the QA systems

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Commands Used for this Week Models

  • *FUNCTION
    • This command can be used to define analytical functions to be used in the same way as curves when applying loads or boundary conditions.
    • There are two ways to define a function, either utilize enormous collection of built in functions of IMPETUS Afea Solver or create user own expression based on the requirement.
    • “smooth_v(-8,0,%t0)” is a built in function used to apply velocity.
    • “-H(%AMP*sin(360*t/%t0)+(%AMP/2)*abs(cos(360*t/%t0)))” is a step function expression that can be defined using *FUNCTION command.

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Commands Used for this Week Models

  • *FUNCTION
    • Below are the few functions user has used to demonstrate function command
    • "sin,cos,abs" %AMP*sin(360*t/%t0)+(%AMP/2)*abs(cos(360*t/%t0))
    • "Minimum value" min(%AMP*sin(720*t/%t0),%AMP*cos(720*t/%t0),0)
    • "Maximum value" max(%AMP*sin((720*t/%t0)+180),%AMP*cos((720*t/%t0)+180),0)
    • "Step function" -H(%AMP*sin(360*t/%t0)+(%AMP/2)*abs(cos(360*t/%t0)))
    • "Sign function" sign(%AMP*sin(360*t/%t0)+(%AMP/2)*abs(cos(360*t/%t0)))
    • "Exponential function" exp(t)/10
    • "Square root function" sqrt(t)
    • "Error function" erf(t)

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Commands Used for this Week Models

  • *INITIAL_DAMAGE_RANDOM
    • INITIAL_DAMAGE_RANDOM command is used to define a randomly distributed initial damage. A distribution function describes the number of defects per unit volume of matter.
    • In this model an interesting way i employed to construct the part, a repeat command is used as follows
    • A N*N rows and columns of single element models are constructed using

N = 32

dx = 0.01

~repeat %N

~repeat %N

*COMPONENT_BOX

[(r1-1)*%N+r2], 1, 1, 1, 1

[(2*r1-2)*%dx], [(2*r2-2)*%dx], 0, [(2*r1-1)*%dx], [(2*r2-1)*%dx], [%dx]

~end_repeat

~end_repeat

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Commands Used for this Week Models

  • *INITIAL_DAMAGE_SURFACE_RANDOM
    • *INITIAL_DAMAGE_SURFACE_RANDOM command is used to define a randomly distributed initial defects on the surface of a body.
    • An inbuilt function is used to apply the load on the glass surface. -smooth_v(%dist,0,%tend) is used to apply velocity to punch

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Commands Used for this Week Models

  • *INITIAL_MATERIAL_DIRECTION
    • The command *INITIAL_MATERIAL_DIRECTION is used to define material directions in anisotrpoic materials.
    • In this command the material direction is defined by use of the element corner nodes.
    • The test consists of three hexahedron elements, one of each type (linear/quadratic/cubic).
    • Each element is assigned a unique material direction. The fiber direction is defined in the X-direction for the linear element, in the Y-direction for the quadratic element and in the Z-direction for the cubic element.
    • The elements are then compressed, first in the X-direction, then in the Y-direction and lastly in the Z-direction.
    • The elements restore the original geometry between the compressions and therefore each compression is uniaxial.

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Commands Used for this Week Models

  • *INITIAL_MATERIAL_DIRECTION_WRAP
    • The fiber orientation in the cylinders are defined using *INITIAL_MATERIAL_DIRECTION_WRAP.
    • The user defines the location and orientation of a “ply” in space. This ply is then wrapped around the component.
    • The vector used for definition of the ply location, x, is defined as (-1, 0, 0) and the vector used for definition of the ply orientation, u, is defined as (0, 0, 1).
    • The angle used for definition of the fiber direction, alpha, is defined as 0 for the first cylinder and 90 for the second cylinder.
    • The fiber orientation for the first cylinder should therefore be in the axial direction, while the the fibers in the second cylinder should be in the circumferential direction.

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Commands Used for this Week Models

  • *MAT_ORTHOTROPIC
    • This is a orthotropic composite model
    • A panel with dimensions (Lx x Ly x Hz) = (0.2m x 0.2m x 0.01m) is stretched 1% in the fiber direction (y).
    • The transverse direction (x) and the thickness direction (z) are free => no stress in these directions.
    • Tensile fiber failure, Compressive fiber failure and Tensile matrix failure has been tested under different loading condition
    • The target values can be accessed in "sensor.out".

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Commands Used for this Week Models

  • *MERGE
    • In this *MERGE command is evaluated by creating nine top plates and nine bottom plates.
    • All bottom plates are meshed with cubic hexahedron elements.
    • Top plates are meshed as linear, quadratic and cubic hexahedron, tetrahedron and pentahedron elements.
    • All the combination of bottom and top plates are arranged and *MERGE command is applied to validate.
    • Boundary condition are applied in the *INCLUDE command

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Commands Used for this Week Models

  • *MERGE_DUPLICATE_NODES
    • This test is undertaken to evaluate *MERGE_DUPLICATED_NODE command, 8 cylindrical components are build using *COMPONENT_CYLINDER command.
    • *MERGE_DUPLICATED_NODE command is used to eliminate/merge any duplicate nodes among the merged parts (Master and Slave entities).
    • Tolerance for the merging nodes has been defined in the command

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Commands Used for this Week Models

  • *MERGE_COHESIVE_FAILURE
    • Four rectangular bars has been constructed in IMPETUS using *COMPONENT_BOX command and
    • Inbuilt function smooth_d(%d,0,%t0) is used to assign the displacement to parts.
    • *MERGE_FAILURE_COHESIVE is the command used to specify failure of a merged interface.
    • Tensile Failure Stress = 95e7
    • Shear Failure Stress = 190e7
    • Modus I energy per unit area = 100.0
    • Modus I energy per unit area = 200.0

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Commands Used for this Week Models

  • *TRANSFORM_MESH_CARTESIAN/CYLINDRICAL
    • A single element part is constructed in IMPETUS, Coordinates of Node ID 1 is at 0,0,0.
    • Using the *TRANSFORM_MESH_CARTESIAN command Node ID 1 is transformed to 10,10,10.
    • Monitor points are defined at each node
    • A local cylindrical coordinate system is defined, and using *FUNCTION command and *TRANSFORM_MESH_CARTESIAN mesh is transformed in cartesian coordinate system.

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Conclusion

  • I have effectively understood and used inbuilt and user defined functions.
  • Built models using repeat command.
  • Understood and utilized all the commands used for this week’s QA system models