Ball plate

This example shows how to use the PyDYNA pre service to create a ball plate model. The executable file for LS-DYNA is ls-dyna_smp_d_R13.0_365-gf8a97bda2a_winx64_ifort190.exe.

Perform required imports

Perform the required imports.

import os
import sys

from ansys.dyna.core.pre import examples, launch_dynapre
from ansys.dyna.core.pre.dynamaterial import MatPiecewiseLinearPlasticity, MatRigid
from ansys.dyna.core.pre.dynamech import (
    AnalysisType,
    Contact,
    ContactSurface,
    ContactType,
    DynaMech,
    NodeSet,
    PartSet,
    ShellFormulation,
    ShellPart,
    SolidFormulation,
    SolidPart,
    Velocity,
)
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 refefring to the README.rst file in this server package.

Once the pre service is running, you can connect a client to it using the host name and port. This code 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]
solution = launch_dynapre(ip=hostname)

Start the solution workflow

NODES and ELEMENTS are read in from the ball_plate.k file. This file also has the PART defined in it, but the section and material fields are empty to begin with.

fns = []
path = examples.ball_plate + os.sep
fns.append(path + "ball_plate.k")
solution.open_files(fns)

ret: true

Create database and control cards

For the D3plots, set simulation termination time, simulation timestep, and output frequency.

solution.set_termination(termination_time=10)

ballplate = DynaMech(AnalysisType.NONE)
solution.add(ballplate)

Define materials

The dynamaterials class is used to define these materials: MAT_RIGID, MAT_PIECEWISE_LINEAR_PLASTICITY,

matrigid = MatRigid(mass_density=7.83e-6, young_modulus=207, poisson_ratio=0.3)
matplastic = MatPiecewiseLinearPlasticity(mass_density=7.83e-6, young_modulus=207, yield_stress=0.2, tangent_modulus=2)

Define section properties and assign materials

Now that you have materials with the material ID corresponding to the Part ID, you can assign these materials to the parts. You can also define section properties, element formulations, and constraints.

plate = ShellPart(1)
plate.set_element_formulation(ShellFormulation.BELYTSCHKO_TSAY)
plate.set_material(matplastic)
plate.set_thickness(1)
plate.set_integration_points(5)
ballplate.parts.add(plate)

ball = SolidPart(2)
ball.set_material(matrigid)
ball.set_element_formulation(SolidFormulation.CONSTANT_STRESS_SOLID_ELEMENT)
ballplate.parts.add(ball)

Define surface-to-surface contacts

Define a single-surface contact between a predefined part set.

selfcontact = Contact(type=ContactType.AUTOMATIC)
surf1 = ContactSurface(PartSet([1, 2]))
selfcontact.set_slave_surface(surf1)
ballplate.contacts.add(selfcontact)

Define nodal single point constraints.

Constrain the nodes in a list of single point constraints (spc).

spc = [
    34,
    35,
    51,
    52,
    68,
    69,
    85,
    86,
    102,
    103,
    119,
    120,
    136,
    137,
    153,
    154,
    170,
    171,
    187,
    188,
    204,
    205,
    221,
    222,
    238,
    239,
    255,
    256,
]
for i in range(1, 19):
    spc.append(i)
for i in range(272, 290):
    spc.append(i)
ballplate.boundaryconditions.create_spc(NodeSet(spc), rx=False, ry=False, rz=False)

Define initial condition.

Use the create_velocity_node method to initialize the velocity components in the desired direction.

for i in range(1, 1652):
    ballplate.initialconditions.create_velocity_node(i, trans=Velocity(0, 0, -10))

Define database outputs

Define the frequency for the D3PLOT file and write out the input file.

solution.set_output_database(glstat=0.1, matsum=0.1, sleout=0.1)
solution.create_database_binary(dt=1)
serverpath = solution.save_file()

Download output file

Download output file from Docker image for the server to your local <working directory>/output/ location.

serveroutfile = "/".join((serverpath, "ball_plate.k"))
downloadpath = os.path.join(os.getcwd(), "output")
if not os.path.exists(downloadpath):
    os.makedirs(downloadpath)
downloadfile = os.path.join(downloadpath, "ball_plate.k")
solution.download(serveroutfile, downloadfile)