ifctruss.solver

All solvers that are supported

Solver

---

source

direct_stiffness_method

 direct_stiffness_method (nodes:pandas.core.frame.DataFrame,
                          bars:pandas.core.frame.DataFrame,
                          point_loads:pandas.core.frame.DataFrame)

	Type	Details
nodes	DataFrame	Pandas DataFrame with information regarding IfcStructuralPointConnection’s
bars	DataFrame	Pandas DataFrame with information regarding IfcStructuralCurveMember’s
point_loads	DataFrame	Pandas DataFrame with information regarding IfcStructuralLoadSingleForce’s
Returns	NamedTuple	NamedTuple with Pandas DataFrame’s and str’s

Example

nodes = pd.DataFrame(
    {
        "Node": pd.Series([2, 1, 3, 4], dtype=int),
        "Coordinate_X": pd.Series([0, 0, -4e3, -4e3], dtype=float),
        "Coordinate_Y": pd.Series([0, 0, 0, 0], dtype=float),
        "Coordinate_Z": pd.Series([3e3, 0, 3e3, 6e3], dtype=float),
        "Translational_X": pd.Series([0, 1, 1, 1], dtype=bool),
        "Translational_Y": pd.Series([1, 1, 1, 1], dtype=bool),
        "Translational_Z": pd.Series([0, 1, 1, 1], dtype=bool),
    }
)

nodes

	Node	Coordinate_X	Coordinate_Y	Coordinate_Z	Translational_X	Translational_Y	Translational_Z
0	2	0.0	0.0	3000.0	False	True	False
1	1	0.0	0.0	0.0	True	True	True
2	3	-4000.0	0.0	3000.0	True	True	True
3	4	-4000.0	0.0	6000.0	True	True	True

bars = pd.DataFrame(
    {
        "Bar": pd.Series([1, 2, 3], dtype=int),
        "Start_node": pd.Series([2, 2, 2], dtype=int),
        "End_node": pd.Series([1, 3, 4], dtype=int),
        "Cross-sectional_area": pd.Series([1e3, 1e3, 1e3], dtype=float),
        "Modulus_of_elasticity": pd.Series([1e3, 1e3, 1e3], dtype=float),
    }
)

bars

	Bar	Start_node	End_node	Cross-sectional_area	Modulus_of_elasticity
0	1	2	1	1000.0	1000.0
1	2	2	3	1000.0	1000.0
2	3	2	4	1000.0	1000.0

point_loads = pd.DataFrame(
    {
        # fmt: off
    "Point_Load": pd.Series([1,], dtype=int,),
    "Node": pd.Series([2,], dtype=int,),
    "Force_X": pd.Series([100e3,], dtype=float,),
    "Force_Y": pd.Series([0,], dtype=float,),
    "Force_Z": pd.Series([-100e3,], dtype=float,),
        # fmt: on
    }
)
point_loads

	Point_Load	Node	Force_X	Force_Y	Force_Z
0	1	2	100000.0	0.0	-100000.0

results = direct_stiffness_method(
    nodes=nodes, bars=bars, point_loads=point_loads
)

results.displacments

	Node	Displacement_X	Displacement_Y	Displacement_Z
0	2	214.814815	0.0	-195.833333

results.forces

	Node	Force_X	Force_Y	Force_Z
1	1	0.000000	0.0	65277.777778
2	3	-53703.703704	0.0	0.000000
3	4	-46296.296296	0.0	34722.222222

(
    displacments,
    forces,
    normal_forces,
    theory_type,
    is_linear,
) = direct_stiffness_method(nodes=nodes, bars=bars, point_loads=point_loads)

normal_forces.style

	Bar	Normal_force	Type_of_normal_force
0	1	-65277.777778	Compressive force
1	2	53703.703704	Tensile force
2	3	57870.370370	Tensile force

theory_type

'FIRST_ORDER_THEORY'

is_linear

True

---

source

calfem

 calfem (nodes:pandas.core.frame.DataFrame,
         bars:pandas.core.frame.DataFrame,
         point_loads:pandas.core.frame.DataFrame)

	Type	Details
nodes	DataFrame	Pandas DataFrame with information regarding IfcStructuralPointConnection’s
bars	DataFrame	Pandas DataFrame with information regarding IfcStructuralCurveMember’s
point_loads	DataFrame	Pandas DataFrame with information regarding IfcStructuralLoadSingleForce’s
Returns	NamedTuple	NamedTuple with Pandas DataFrame’s and str’s

Example

results_calfem = calfem(nodes=nodes, bars=bars, point_loads=point_loads)

results_calfem.displacments

	Node	Displacement_X	Displacement_Y	Displacement_Z
0	2	214.814815	0.0	-195.833333

results_calfem.forces

	Node	Force_X	Force_Y	Force_Z
1	1	0.000000	0.0	65277.777778
2	3	-53703.703704	0.0	0.000000
3	4	-46296.296296	0.0	34722.222222

results_calfem.normal_forces

	Bar	Normal_force	Type_of_normal_force
0	1	-65277.777778	Compressive force
1	2	53703.703704	Tensile force
2	3	57870.370370	Tensile force

Comparison

Resulate

Test whether calfem calculates the same results as direct_stiffness_method:

import numpy as np

assert np.all(
    np.isclose(
        results.normal_forces["Normal_force"],
        results_calfem.normal_forces["Normal_force"],
    )
)

assert np.all(
    np.isclose(results.forces["Force_X"], results_calfem.forces["Force_X"])
)

assert np.all(
    np.isclose(results.forces["Force_Y"], results_calfem.forces["Force_Y"])
)

assert np.all(
    np.isclose(results.forces["Force_Z"], results_calfem.forces["Force_Z"])
)

assert np.all(
    np.isclose(
        results.displacments["Displacement_X"],
        results_calfem.displacments["Displacement_X"],
    )
)

assert np.all(
    np.isclose(
        results.displacments["Displacement_Y"],
        results_calfem.displacments["Displacement_Y"],
    )
)

assert np.all(
    np.isclose(
        results.displacments["Displacement_Z"],
        results_calfem.displacments["Displacement_Z"],
    )
)

Speed

Compare the speed of direct_stiffness_methodand calfem

import timeit
import statistics

execution_times = timeit.repeat(
    lambda: direct_stiffness_method(
        nodes=nodes, bars=bars, point_loads=point_loads
    ),
    number=200,
    repeat=7,
)

mean_time = statistics.mean(execution_times)
stdev_time = statistics.stdev(execution_times)

print("Mean execution time:", mean_time, "seconds")
print("Standard deviation:", stdev_time, "seconds")

Mean execution time: 2.5156487490000603 seconds
Standard deviation: 0.3370494115779167 seconds

execution_times = timeit.repeat(
    lambda: calfem(nodes=nodes, bars=bars, point_loads=point_loads),
    number=200,
    repeat=7,
)

mean_time = statistics.mean(execution_times)
stdev_time = statistics.stdev(execution_times)

print("Mean execution time:", mean_time, "seconds")
print("Standard deviation:", stdev_time, "seconds")

Mean execution time: 3.4454708377145704 seconds
Standard deviation: 0.19648677400024356 seconds