ShearFiber

ShearFiber#

A ShearFiber section is used to model a Frame section with shear deformation. The section is defined by a collection of fibers that discretize the cross-section.

Model.section("ShearFiber", tag, **kwds)
Parameters:

tag (integer) – unique Section tag

../../../_images/w8x28.png

Example of an AISC W8x28 section discretized with fibers and rendered with veux.#

The fiber method is used to populate the section with fibers. The required arguments are:

Model.fiber((y, z), A, tag, warp, section)#
Parameters:

  • y (float) – \(y\)-coordinate of the fiber

  • z (float) – \(z\)-coordinate of the fiber

  • A (float) – area of the fiber

  • material (integer) – tag of a preexisting material created with the Materials method.

  • warp (tuple) – tuple of up to three warping modes. A warping mode is a list of three floats. The first float is the amplitude of the mode, and the second and third floats are derivatives with respect to the \(y\) and \(z\) coordinates, respectively.

  • section (integer) – tag of the section to which the fiber belongs. This argument must be passed by keyword.

In general, the warp modes are scaled by independent amplitude fields which introduce additional degrees of freedom. When no additional degrees of freedom are provided by the model, elements in the Frame library will constrain these fields to match an appropriate strain field.

The valid eleResponse queries are

  • "force", and

  • "deformation".

Valid setParameter targets are

  • "warp", fiber, field where fiber is an integer identifying a fiber and field is an integer identifying the warping field.

Examples#

The following example demonstrates how to create a ShearFiber section representing a circle.

import xara
from math import pi
radius = 0.5
center = (0.0, 0.0)
area   = pi * radius**2

model = xara.Model(ndm=3, ndf=6)

model.material("ElasticIsotropic", 1, E=200e9, nu=0.3)

model.section("ShearFiber", 1)
model.fiber(center, area, material=1, section=1)

The following example uses the xsection library to create a ShearFiber section representing an AISC W8x28 section.

import xara
from xara.units import english
from xsection.library import from_aisc

model = xara.Model(ndm=3, ndf=6)

model.material("ElasticIsotropic", 1, E=200e9, nu=0.3)

shape = from_aisc("W8x28", units=english)

model.section("ShearFiber", 1)
for fiber in shape.fibers:
    model.fiber(**fiber, material=1, section=1)
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