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Optimization

Below is a minimal working example that performs a topology optimization. This will run a compliance minimization with OC method.

Optimizer Configuration, and Run

import sktopt

cfg = sktopt.core.optimizers.LogMOC_Config(
     vol_frac=0.6,
     max_iters=40,
     record_times=40,
     export_img=True
 )
 optimizer = sktopt.core.LogMOC_Optimizer(cfg, mytask)
 optimizer.parameterize()
 optimizer.optimize()

But before running the optimization, we need to set up the task configuration and the design variables.

Task Definition

Shape modeling and its basis function

import skfem
import sktopt

x_len = 8.0
y_len = 8.0
z_len = 1.0
mesh_size = 0.2

mesh = sktopt.mesh.toy_problem.create_box_hex(
    x_len, y_len, z_len, mesh_size
)
e = skfem.ElementVector(skfem.ElementHex1())
basis = skfem.Basis(mesh, e, intorder=2)

Load Basis from Model File

import skfem
import sktopt

mesh_path = "./data/model.msh"
basis = sktopt.mesh.loader.basis_from_file(mesh_path, intorder=3)

Task Configuration

dirichlet_nodes = sktopt.mesh.utils.get_nodes_indices_in_range(
    basis, (0.0, 0.05), (0.0, y_len), (0.0, z_len)
)
dirichlet_dir = "all"

F_nodes_0 = sktopt.mesh.utils.get_nodes_indices_in_range(
    basis, (x_len, x_len), (y_len, y_len), (0, z_len)
)
F_nodes_1 = sktopt.mesh.utils.get_nodes_indices_in_range(
    basis, (x_len, x_len), (0, 0), (0, z_len)
)
F_nodes = [F_nodes_0, F_nodes_1]
F_dir = ["u^2", "u^2"]
F = [-100, 100]
design_elements = sktopt.mesh.utils.get_elements_in_box(
    mesh,
    (0.0, x_len), (0.0, y_len), (0.0, z_len)
)

mytask = sktopt.mesh.task.TaskConfig.from_nodes(
    E0,
    nu,
    basis,
    dirichlet_nodes,
    dirichlet_dir,
    F_nodes,
    F_dir,
    F,
    design_elements
)

Results and Visualization

Results and Visualization

The results of the optimization are stored in the directory specified by cfg.dst_path. For example, it contains visualizations of the density distribution, as well as graphs showing the evolution of various parameters during the optimization process, such as the density field, volume fraction, and sensitivity values.