Properties

Adding properties

To associate Material and Section objects to specific elements, an ElementProperties object is used. Without creating an association between these objects, the materials and sections will exist as objects in the main Structure object, but they will be unassigned to any of the structure’s elements. The ElementProperties class is first imported from module compas_fea.structure.element_properties, and then an object is created and added to the .element_properties dictionary of the Structure object with method .add(). The argument elset or elements can be an element set string name or a list of elements for assigning the properties to many similar elements (either elements or elset should be given, not both.). The material and section arguments are the string names of the respective Material and Section objects to link together, while the name is the key used to store and represent the ElementProperties object.

from compas_fea.structure import ElementProperties as Properties

mdl.add(Properties(name='ep_circ', material='mat_elastic', section='sec_circ', elset='elset_beams'))

Note: A SpringElement does not require a material to be defined, and is handed None by default. A spring will define itself through its SpringSection and the elements it is linked to.

Accessing and editing properties

At any time, the input data of an ElementProperties object can be viewed or manipulated as usual through the object’s string key and attributes, and also by printing the object to the terminal.

>>> mdl.element_properties['ep_circ']  # ElementProperties object `ep_circ`
ElementProperties(ep_circ)

>>> print(mdl.element_properties['ep_circ'])  # print a summary


compas_fea ElementProperties object
-----------------------------------
name          : ep_circ
material      : mat_elastic
section       : sec_circ
elset         : elset_beams
elements      : None
rebar         : {}

>>> mdl.element_properties['ep_circ'].section  # view section attribute
'sec_circ'

>>> mdl.element_properties['ep_circ'].material  # view material attribute
'mat_elastic'

>>> mdl.element_properties['ep_circ'].elset  # view associated element set
'elset_beams'

Reinforcement

Reinforcement layers for shell and membrane elements can be added to an ElementProperties object through the dictionary rebar. This dictionary has the keys as the name of each reinforcement layer, and the item as a dictionary with the following data: pos the float position of the reinforcement layer above or below the section’s middle axis, spacing the float spacing between the reinforcing bars for that layer, material string name of the Material object, dia the float diameter of each bar, and angle the float angle the reinforcement layer makes with the orientation of the section’s local axes. A call to the ElementProperties class could then look like:

rebar = {
    'layer_2': {'pos': -0.045, 'spacing': 0.150, 'material': 'steel', 'dia': 0.010, 'angle': 90},
    'layer_1': {'pos': -0.050, 'spacing': 0.150, 'material': 'steel', 'dia': 0.010, 'angle': 0},
}

mdl.add(ElementProperties(name='ep_rc', material='concrete', section='shell', elset='slab', rebar=rebar))