Material

This class is provided as a demonstration example.

Material class methods

method

input

returns

description

__init__(…)

parameters as {‘E’:10.0}

constructor. Sets parameters for this material and initializes all internal variables

getArea()

A

return cross section area from parameters[‘A’]

getStress()

σ

request axial stress

getStiffness

Et

request axial stiffness

setStrain(eps)

strain ε

update state for a user provided axial strain value

Element class variables

name

type

description

params

dict

default parameters: {‘E’:100., ‘nu’:0.0, ‘fy:1.0e30} Holds user provided parameters (MOE, Poisson’s ratio, yield stress)

plastic_strain

float

internal state variable.

sig

float

holds current stress

Et

float

holds current materil tangent modulus

Equations

  1. Elastic trial state:

    1.1 σ=E(εεP)

    1.2 Et=E

  2. Yield check: f=||σ||fy

  3. IF f0:

    3.1. ΔεP=sign(σ)fE

    3.2. σ=σEΔεP

    3.3. Et=EtE