anaStruct 2D Frames and Trusses

Analyse 2D Frames and trusses for slender structures. Determine the bending moments, shear forces, axial forces and displacements.

Installation

For the actively developed version: $ pip install git+https://github.com/ritchie46/anaStruct.git

Or for a release: $ pip install anastruct

Read the docs!

Documentation

Questions

Got a question? Please ask on gitter.

Includes

• trusses :heavycheckmark:
• beams :heavycheckmark:
• moment lines :heavycheckmark:
• axial force lines :heavycheckmark:
• shear force lines :heavycheckmark:
• displacement lines :heavycheckmark:
• hinged supports :heavycheckmark:
• fixed supports :heavycheckmark:
• spring supports :heavycheckmark:
• q-load in elements direction :heavycheckmark:
• point loads in global x, y directions on nodes :heavycheckmark:
• dead load :heavycheckmark:
• q-loads in global y direction :heavycheckmark:
• hinged elements :heavycheckmark:
• rotational springs :heavycheckmark:
• non-linear nodes :heavycheckmark:
• geometrical non linearity :heavycheckmark:
• load cases and load combinations :heavycheckmark:
• generic type of section - rectangle and circle :heavycheckmark:
• EU, US, UK steel section database :heavycheckmark:

Examples

```python from anastruct import SystemElements import numpy as np

ss = SystemElements() element_type = 'truss'

Create 2 towers

width = 6 span = 30 k = 5e3

create triangles

y = np.arange(1, 10) * np.pi x = np.cos(y) * width * 0.5 x -= x.min()

for length in [0, span]: xleftcolumn = np.ones(y[::2].shape) * x.min() + length xrightcolumn = np.ones(y[::2].shape[0] + 1) * x.max() + length

# add triangles
ss.add_element_grid(x + length, y, element_type=element_type)
# add vertical elements
ss.add_element_grid(x_left_column, y[::2], element_type=element_type)
ss.add_element_grid(x_right_column, np.r_[y[0], y[1::2], y[-1]], element_type=element_type)

ss.add_support_spring(
    node_id=ss.find_node_id(vertex=[x_left_column[0], y[0]]),
    translation=2,
    k=k)
ss.add_support_spring(
    node_id=ss.find_node_id(vertex=[x_right_column[0], y[0]]),
    translation=2,
    k=k)

add top girder

ss.addelementgrid([0, width, span, span + width], np.ones(4) * y.max(), EI=10e3)

Add stability elements at the bottom.

ss.addtrusselement([[0, y.min()], [width, y.min()]]) ss.addtrusselement([[span, y.min()], [span + width, y.min()]])

for el in ss.elementmap.values(): # apply wind load on elements that are vertical if np.isclose(np.sin(el.ai), 1): ss.qload( q=1, element_id=el.id, direction='x' )

ss.showstructure() ss.solve() ss.showdisplacement(factor=2) ss.showbendingmoment()

```

```python from anastruct import SystemElements

ss = SystemElements(EA=15000, EI=5000)

Add beams to the system.

ss.addelement(location=[0, 5]) ss.addelement(location=[[0, 5], [5, 5]]) ss.add_element(location=[[5, 5], [5, 0]])

Add a fixed support at node 1.

ss.addsupportfixed(node_id=1)

Add a rotational spring support at node 4.

ss.addsupportspring(node_id=4, translation=3, k=4000)

Add loads.

ss.pointload(Fx=30, nodeid=2) ss.qload(q=-10, elementid=2)

Solve

ss.solve()

Get visual results.

ss.showstructure() ss.showreactionforce() ss.showaxialforce() ss.showshearforce() ss.showbendingmoment() ss.showdisplacement() ```

Real world use case.

Non linear water accumulation analysis