Poleplan: Basics

The following example demonstrates how a poleplan object can be created from a system object.

We will use System-object that was modeled in the example “Identifying an Unstable System”.

Finally, the poleplan is visualized.

You can find the example as an executable Python file here.

Import Modules

We start by importing the required classes for defining and visualizing the poleplan.

from sstatics.core.preprocessing import (Node, Bar, Material, CrossSection, System)
from sstatics.core.solution import Poleplan
from sstatics.core.postprocessing.graphic_objects import ObjectRenderer, SystemGeo

Define System

In this step, we will use System-object that was modeled in the example “Identifying an Unstable System”.

Here, we only show the system modeling in a concise form, without additional explanations.

The detailed description of the modeling process can be found in the linked example.

# define cross-section
c_1 = CrossSection(mom_of_int=2769, area=76.84, height=20, width=10, shear_cor=0.1)

# define material
m_1 = Material(young_mod=21000, poisson=0.1, shear_mod=8100, therm_exp_coeff=0.1)

# define Node
node_1 = Node(0, 0, u='fixed', w='fixed')
node_2 = Node(200, 0)
node_3 = Node(400, 0, w='fixed')
node_4 = Node(600, 0)

# define Bar
bar_1 = Bar(node_1, node_2, c_1, m_1, hinge_phi_j=True)
bar_2 = Bar(node_2, node_3, c_1, m_1)
bar_3 = Bar(node_3, node_4, c_1, m_1)

bars = [bar_1, bar_2, bar_3]

# define System
system = System(bars)

# Visualize system
ObjectRenderer(SystemGeo(system, show_bar_text=True), 'mpl').show(show_axis=False)

Define Poleplan

The poleplan can be accessed directly as an attribute of the System class:

poleplan = Poleplan(system=system)

Visualize Poleplan

We can visualize the Poleplan using the plot() method of th class.

This allows us to see the kinematic configuration of the system.

poleplan.plot()

Result:

The diagram shows the poleplan and the displacement figure (in red).

The kinematic chain consists of two chains:

• Chain 1 (shown in purple) has its absolute pole at Node 1 (0, 0).

• Chain 2 (shown in yellow) has its absolute pole at Node 3 (0, 400).

• The relative pole (1|2) is located at Node 2 (0, 200).