#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# ---------------------------------------------------------------------
#
# _____ _ _ _ _____ _____
# | ____|__| | ___| |_ _____(_)___ ___| ___| ____|
# | _| / _` |/ _ \ \ \ /\ / / _ \ / __/ __| |_ | _|
# | |__| (_| | __/ |\ V V / __/ \__ \__ \ _| | |___
# |_____\__,_|\___|_| \_/\_/ \___|_|___/___/_| |_____|
#
#
# Unit of Strength of Materials and Structural Analysis
# University of Innsbruck,
# 2017 - today
#
# Matthias Neuner matthias.neuner@uibk.ac.at
#
# This file is part of EdelweissFE.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# The full text of the license can be found in the file LICENSE.md at
# the top level directory of EdelweissFE.
# ---------------------------------------------------------------------
from abc import ABC, abstractmethod
import numpy as np
from edelweissfe.models.femodel import FEModel
from edelweissfe.timesteppers.timestep import TimeStep
from edelweissfe.variables.scalarvariable import ScalarVariable
[docs]class ConstraintBase(ABC):
@abstractmethod
def __init__(self, name: str, options: dict, model: FEModel):
"""The constraint base class.
Constraints can act on nodal variables, and scalar variables.
If scalar variables are required, the can be created on demand by
defining
:func:`~ConstraintBase.getNumberOfAdditionalNeededScalarVariables` and
:func:`~ConstraintBase.assignAdditionalScalarVariables`, which are called at the beginning of an analysis.
If scalar variables are used, EdelweissFE expects the layout of the external load vector PExt
(and the stiffness) to be of the form
.. code-block:: console
[ node 1 - dofs field 1,
node 1 - dofs field 2,
node 1 - ... ,
node 1 - dofs field n,
node 2 - dofs field 1,
... ,
node N - dofs field n,
scalar variable 1,
scalar variable 2,
... ,
scalar variable J ].
Parameters
----------
name
The name of the constraint.
options
A dictionary containing the options for the constraint.
model
A dictionary containing the model tree.
"""
self.scalarVariables = []
@property
@abstractmethod
def nodes(self) -> list:
"""The nodes this constraint is acting on."""
@property
@abstractmethod
def fieldsOnNodes(self) -> list:
"""The fields on the nodes this constraint is acting on."""
@property
@abstractmethod
def nDof(self) -> int:
"""The total number of degrees of freedom this constraint is associated with."""
[docs] def getNumberOfAdditionalNeededScalarVariables(
self,
) -> int:
"""This method is called to determine the additional number of scalar variables
this Constraint needs.
Returns
-------
int
Number of ScalarVariables required.
"""
return 0
[docs] def assignAdditionalScalarVariables(self, scalarVariables: list[ScalarVariable]):
"""Assign a list of scalar variables associated with this constraint.
Parameters
----------
list
The list of ScalarVariables associated with this constraint.
"""
self.scalarVariables = scalarVariables
[docs] @abstractmethod
def applyConstraint(
self,
U_np: np.ndarray,
dU: np.ndarray,
PExt: np.ndarray,
V: np.ndarray,
timeStep: TimeStep,
):
"""Apply the constraint. Add the contributions to the external load vector and the system matrix.
Parameters
----------
U_np
The current total solution vector.
dU
The current increment since the last time the constraint was applied.
PExt
The external load vector.
K
The system (stiffness) matrix.
dT
The time increment.
time
The current step and total time.
"""