linear_elasticity/truss_bridge.py

Description

An example demonstrating the usage of the truss elements in 2D. The bridge structure is fixed on the left and supported on the right.

Running the simulation:

sfepy-run sfepy/examples/linear_elasticity/truss_bridge.py

Viewing the results:

sfepy-view bridge.vtk -f u:wu:p0 1:vw:p0 S:e:p1 --2d-view

source code

r"""
An example demonstrating the usage of the truss elements in 2D.
The bridge structure is fixed on the left and supported on the right.

Running the simulation::

  sfepy-run sfepy/examples/linear_elasticity/truss_bridge.py

Viewing the results::

  sfepy-view bridge.vtk -f u:wu:p0 1:vw:p0 S:e:p1 --2d-view
"""
import numpy as nm
from sfepy.base.base import Struct
from sfepy import data_dir


def post_process(out, pb, state, extend=False):
    valS = pb.evaluate('ev_lin_truss_force.0.Truss(truss.EA, u)', mode='el_avg')
    out['S'] = Struct(name='output_data', mode='cell',
                      region_name='Truss', data=valS)

    print('### nodal displacements: ')
    print(out['u'].data)

    return out


def get_pars(ts, coors, mode=None, **kwargs):
    if mode == 'qp':
        EA = nm.array([2, 2, 2, 2, 2, 2,
                       10, 10, 10, 10, 10, 10,
                       3, 3, 3, 3, 3,
                       1, 1, 1, 1]).reshape(-1, 1, 1) * 1000

        return {'EA': EA}


filename_mesh = data_dir + "/meshes/2d/bridge.vtk"

options = {
    'post_process_hook': 'post_process',
}

regions = {
    'Truss': 'cells of group 1',
    'Left': ('vertices in (x < 0.01)', 'vertex'),
    'Right': ('vertices in (x > 59.99)', 'vertex'),
    'Bottom': ('vertex 2, 4, 6, 8, 10', 'vertex'),
}

materials = {
    'force': ({'.val': nm.array([[0, -10],
                                 [0, -10],
                                 [0, -16],
                                 [0, -10],
                                 [0, -10]])},),
    'truss': 'get_pars',
}

functions = {
    'get_pars': (get_pars,),
}

fields = {
    'displacement': ('real', 'vector', 'Truss', 1),
}

variables = {
    'u': ('unknown field', 'displacement'),
    'v': ('test field', 'displacement', 'u'),
}

ebcs = {
    'Fixed_Left': ('Left', {'u.all': 0.0}),
    'Support_Right': ('Right', {'u.1': 0.0}),
}

equations = {
    'balance_of_forces':
    """dw_lin_truss.0.Truss(truss.EA, v, u)
     = dw_point_load.0.Bottom(force.val, v)""",
}

solvers = {
    'ls': ('ls.auto_direct', {}),
    'newton': ('nls.newton', {}),
}