Note

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Implicit model#

This example shows how to create and use an implicit dynamic roof crush model.

Perform required imports#

Peform the required imports.

import os
import sys


from ansys.dyna.core.pre import launch_dynapre
from ansys.dyna.core.pre.dynamech import (
    DynaMech,
    Curve,
    BeamPart,
    ShellPart,
    NodeSet,
    PartSet,
    TimestepCtrol,
    Contact,
    ContactType,
    ContactCategory,
    ContactSurface,
    DOF,
    OffsetType,
    AnalysisType
)
from ansys.dyna.core.pre.dynamaterial import (
    MatNull,
    MatRigid,
    MatSpotweld,
    MatModifiedPiecewiseLinearPlasticity,
    MatPiecewiseLinearPlasticity,
)
from camry_rc_data import *
from ansys.dyna.core.pre import examples
from ansys.dyna.core.pre.misc import check_valid_ip

Start the `pre` service#

Before starting the pre service, you must ensure that the Docker container for this service has been started. For more information, see “Start the Docker container for the pre service” in https://dyna.docs.pyansys.com/version/stable/index.html.

The pre service can also be started locally, please download the latest version of ansys-pydyna-pre-server.zip package from ansys/pydyna and start it refering to the README.rst file in this server package.

Once the pre service is running, you can connect a client to it using the hostname and port. This example uses the default localhost and port ("localhost" and "50051" respectively).

hostname = "localhost"
if len(sys.argv) > 1 and check_valid_ip(sys.argv[1]):
    hostname = sys.argv[1]
camry_solution = launch_dynapre(ip = hostname)

Import initial mesh data#

Import the initial mesh data (nodes and elements), which includes the vehicle data, weld data, and platen data.

fns = []
path = examples.camry_rc + os.sep
fns.append(path + "Camry_RC_main.k")
fns.append(path + "501_RIG_BAR_roof_crush_platen5.key")
fns.append(path + "Camry_V1_NoSusAndPowerTrain_impl7.k")
fns.append(path + "Camry_V1_NoSusAndPowerTrain_impl7_nodes.k")
fns.append(path + "roof_welds.k")
fns.append(path + "weld7.k")
fns.append(path + "xtra_sw.k")
camry_solution.open_files(fns)

ret: true

Define global control cards#

Because roof crush is a quasi-static loading case, you must run this model as an implicit dynamic solution. Define the global control cards. From the dynasolution class, set the termination time and the frequency for the database ASCII options.

camry_solution.set_termination(10)

Use the implicit analysis methods in the dynamech class to define the IMPLICIT control cards.

camry = DynaMech(analysis=AnalysisType.EXPLICIT)
camry_solution.add(camry)

Set the automatic timestep control flag and the optimal equilibrium iteration count per timestep.

camry.implicitanalysis.set_initial_timestep_size(0.1)
camry.implicitanalysis.set_timestep(
    control_flag=TimestepCtrol.AUTOMATICALLY_ADJUST_TIMESTEP_SIZE,
    Optimum_equilibrium_iteration_count=511,
)

Use the set_dynamic() method to set the IMASS value to 1 and assign the gamma and beta values.

camry.implicitanalysis.set_dynamic(gamma=0.6, beta=0.38)

If normal modes must be extracted, use the set_eigenvalue() method. The set_solution() method defines NSOLVR as 12 (Nolinear with BFGS update).

camry.implicitanalysis.set_eigenvalue()
camry.implicitanalysis.set_solution(iteration_limit=1,
    stiffness_reformation_limit=50, absolute_convergence_tolerance=-100
)

Define materials#

This model uses four classes of material: MAT_NULL, MAT_RIGID, MAT_SPOTWELD, and MAT_PIECEWISE_LINEAR_PLASTICITY. Use the dynamaterial class to define these materials.

matnull = MatNull(mass_density=6e-11)
matrigid = MatRigid(mass_density=7.890e-09, young_modulus=2.100e05, poisson_ratio=0.3)
matplaten = MatRigid(
    mass_density=7.80e-09,
    young_modulus=2.00e05,
    poisson_ratio=0.3,
    center_of_mass_constraint=1,
    rotational_constraint=7,
)
spotweldharden2100 = MatSpotweld(
    mass_density=7.850e-09,
    young_modulus=2.100e05,
    poisson_ratio=0.3,
    yield_stress=510,
    plastic_hardening_modulus=2100,
)
spotweldharden2200 = MatSpotweld(
    mass_density=7.850e-09,
    young_modulus=2.100e05,
    poisson_ratio=0.3,
    yield_stress=510,
    plastic_hardening_modulus=2200,
)
windowshield = MatModifiedPiecewiseLinearPlasticity(
    mass_density=2.355e-09,
    young_modulus=7.000e04,
    poisson_ratio=0.22,
    yield_stress=30,
    tangent_modulus=1400,
    plastic_strain_to_failure=0.015,
    integration_points_number=1,
)
windowsrear = MatModifiedPiecewiseLinearPlasticity(
    mass_density=2.425e-09,
    young_modulus=7.000e04,
    poisson_ratio=0.22,
    yield_stress=30,
    tangent_modulus=1400,
    plastic_strain_to_failure=0.015,
    integration_points_number=1,
)
plastic300 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=300, tangent_modulus=5000
)
plastic250 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=250, tangent_modulus=5000
)
plastic360 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=360, tangent_modulus=5000
)
plastic180 = MatPiecewiseLinearPlasticity(
    mass_density=7.850e-09, young_modulus=210000, yield_stress=180, tangent_modulus=5000
)
plastic450 = MatPiecewiseLinearPlasticity(
    mass_density=7.850e-09, young_modulus=210000, yield_stress=450, tangent_modulus=5000
)
plastic1300 = MatPiecewiseLinearPlasticity(
    mass_density=7.850e-09, young_modulus=210000, yield_stress=1300, tangent_modulus=5000
)
plastic400 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=400, tangent_modulus=5000
)
plastic500 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=500, tangent_modulus=5000
)
plastic675 = MatPiecewiseLinearPlasticity(
    mass_density=7.850e-09, young_modulus=210000, yield_stress=675, tangent_modulus=5000
)
plastic310 = MatPiecewiseLinearPlasticity(
    mass_density=2.255e-09, young_modulus=70000, yield_stress=310, tangent_modulus=5000
)
plastic220 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=220, tangent_modulus=5000
)
plastic220_410 = MatPiecewiseLinearPlasticity(
    mass_density=7.890e-09, young_modulus=210000, yield_stress=220, tangent_modulus=410
)

Assign section and material properties#

Once all materials are explicitly defined, these material IDs must be cross-referenced in the PART card. You use the set_material() method for this. Because many parts share common materials, the assignment happens within a loop. Within the loop, the set_element_formulation() method is called to assign the elform for the beam and shell elements. Accordingly, either the beam diameter or the shell thickness is also defined. To identify the part ID that has a particular material type, a predefined list is made available in the camry_rc_data.py file, which this script reads.

for bpart in beamparts:
    part = BeamPart(bpart[0])
    if part.id in [50000002]:
        part.set_material(spotweldharden2200)
    else:
        part.set_material(spotweldharden2100)
    part.set_element_formulation(bpart[1])
    part.set_diameter(bpart[2])
    camry.parts.add(part)

for spart in shellparts:
    part = ShellPart(spart[0])
    if part.id in [1463, 1464]:
        part.set_material(matnull)
    elif part.id in [417, 419, 530, 532, 585, 586, 587, 588]:
        part.set_material(matrigid)
    elif part.id in [50000001]:
        part.set_material(matplaten)
    elif part.id in [290]:
        part.set_material(windowshield)
    elif part.id in [291]:
        part.set_material(windowsrear)
    elif part.id in partswithmat300:
        part.set_material(plastic300)
    elif part.id in partswithmat250:
        part.set_material(plastic250)
    elif part.id in partswithmat360:
        part.set_material(plastic360)
    elif part.id in partswithmat180:
        part.set_material(plastic180)
    elif part.id in partswithmat450:
        part.set_material(plastic450)
    elif part.id in partswithmat400:
        part.set_material(plastic400)
    elif part.id in partswithmat500:
        part.set_material(plastic500)
    elif part.id in [57]:
        part.set_material(plastic1300)
    elif part.id in [286]:
        part.set_material(plastic675)
    elif part.id in [5000000]:
        part.set_material(plastic310)
    elif part.id in [5000006]:
        part.set_material(plastic220)
    elif part.id in [5000007]:
        part.set_material(plastic220_410)
    else:
        pass
    part.set_element_formulation(spart[1])
    part.set_thickness(spart[2])
    camry.parts.add(part)

Generate keywords for spotwelds and nodal rigid bodies#

The camry_rc_data.py file contains the predefined node pairs and node sets required for the CONSTRAINED_SPOTWELD and CONSTRAINED_NODAL_RIGID_BODY definitions. Loop through these lists to generate the appropriate keywords.

for sw in spotweld:
    camry.constraints.create_spotweld(nodeid1=sw[0], nodeid2=sw[1])

for cnrb in cnrbs:
    camry.constraints.create_cnrb(nodeset=NodeSet(cnrb))

Define contacts#

There are three contacts defined in this model:

Automatic single surface contact for the BIW self contact
Surface-to-surface contact between the platen and the BIW self contact
Tied contact for the spotweld beams

Use the ContactSurface() method to set the SSTYPE and MSTYPE. The PartSet() method accepts the name of a list and converts it to PART_SET_LIST. Notice how the contact type and category can be used to create the three different type of contacts for this model.

selfcontact = Contact(type=ContactType.AUTOMATIC)
selfcontact.set_mortar()
selfcontact.set_friction_coefficient(static=0.2)
surf1 = ContactSurface(PartSet(vehicle))
selfcontact.set_slave_surface(surf1)
camry.contacts.add(selfcontact)

platebiw = Contact(type=ContactType.AUTOMATIC, category=ContactCategory.SURFACE_TO_SURFACE_CONTACT)
platebiw.set_mortar()
platebiw.set_friction_coefficient(static=0.2, dynamic=0.2)
surf1 = ContactSurface(PartSet(biw))
surf2 = ContactSurface(PartSet(platen))
platebiw.set_slave_surface(surf1)
platebiw.set_master_surface(surf2)
camry.contacts.add(platebiw)

swcontact = Contact(
    type=ContactType.TIED,
    category=ContactCategory.SHELL_EDGE_TO_SURFACE_CONTACT,
    offset=OffsetType.CONSTRAINED_OFFSET,
)
spotweldbeam = ContactSurface(PartSet(spotweldbeams))
spotweldbeam.set_contact_thickness(thickness=-0.9)
spotweldsurface = ContactSurface(PartSet(spotweldsurfaces))
spotweldsurface.set_contact_thickness(thickness=-0.9)
swcontact.set_slave_surface(spotweldbeam)
swcontact.set_master_surface(spotweldsurface)
camry.contacts.add(swcontact)

Define SPCs#

You can use the boundaryconditions class to define both SPCs and prescribed motions. The bottom of the BIW is SPCed by selecting a few nodes. The prescribed motion is then assigned to the platen.

camry.boundaryconditions.create_spc(NodeSet(spc))

crv = Curve(
    x=[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9.77, 100],
    y=[0, 13, 26, 39, 52, 65, 78, 91, 104, 117, 127, 127],
)
platen = PartSet([50000001])
camry.boundaryconditions.create_imposed_motion(
    platen, crv, dof=DOF.X_TRANSLATIONAL, scalefactor=-0.0802216
)
camry.boundaryconditions.create_imposed_motion(
    platen, crv, dof=DOF.Y_TRANSLATIONAL, scalefactor=-0.0802216
)
camry.boundaryconditions.create_imposed_motion(
    platen, crv, dof=DOF.Z_TRANSLATIONAL, scalefactor=-0.0802216
)

Define database cards and save input file#

Define the frequency of output for the binary and ASCII database outputs and save the input file.

camry_solution.create_database_binary(dt=0.001)
camry_solution.set_output_database(
    elout=0.0001,
    glstat=0.0001,
    matsum=0.0001,
    nodout=0.0001,
    rbdout=0.0001,
    rcforc=0.0001,
    secforc=0.0001,
)

camry_solution.save_file()

'/server/output'

Total running time of the script: (0 minutes 14.372 seconds)

Gallery generated by Sphinx-Gallery

Implicit model#

Perform required imports#

Start the pre service#

Import initial mesh data#

Define global control cards#

Define materials#

Assign section and material properties#

Generate keywords for spotwelds and nodal rigid bodies#

Define contacts#

Define SPCs#

Define database cards and save input file#

Start the `pre` service#