Example 4711: Error estimation for L-shaped problem using patch fitting and bilinear elements

A linear elastic plane stress problem is solved on an L-shaped domain using bilinear
elements. Then fields of the three components of stress (stress in x, y and shear stress)
are then fitted using the superconvergent patch recovery technique.
The percentage relative error in the strain energy norm is then computed.

The comfile run by this example is as follows:

#Example_4711 An error estimation problem
 
FEM
FEM define nodes;r;L;example
FEM define window
FEM draw nodes
FEM define bases;r;example      # Defines two bilinear bases,
                                # one for solving the problem and one for patch fitting
FEM define elements;r;example
FEM draw lines
FEM draw elements
FEM define fibre;d
FEM define element;r;;example fibre
FEM define equation;r;example lock
FEM define material;r;example
FEM group nodes 1,8,15,22,29,33,37 as left_edge
FEM group nodes 7,14,21,28 as right_edge
FEM group nodes 37,38,39,40 as top
FEM define initial;r;example
FEM draw reactions
FEM draw nodes
FEM define solve;r;example
FEM solve
FEM draw lines deformed dotted scale 5
FEM define field;r;example  # Define 3 fields, for stress in x dirn, y dirn and shear stress
FEM define elements;r;example field
FEM define fit;r;example gauss patch
FEM update gauss stress reference components basis 2
FEM fit patch nodes 1..40 basis 2
FEM update gauss stress reference components basis 1
FEM evaluate error
FEM draw element error
refresh graphics
FEM draw field field 1
refresh graphics
FEM draw field field 2
refresh graphics
FEM draw field field 3
FEM

Files used by this example are:

Name              Modified     Size

example_4711.com  10-Apr-2000  1.2k
l.ipbase          10-Apr-2000  2.1k
l.ipelem          10-Apr-2000  8.6k
l.ipelfb          10-Apr-2000  3.8k
l.ipelfd          10-Apr-2000  6.8k
l.ipequa          26-May-2003  1.8k
l.ipfiel          10-Apr-2000  8.5k
l.ipfit           10-Apr-2000  620 
l.ipinit          10-Apr-2000  808 
l.ipmate          10-Apr-2000  1.4k
l.ipnode          10-Apr-2000  5.4k
l.ipsolv          13-Apr-2007  1.0k
readme            10-Apr-2000  126 
test_output       10-Apr-2000   43 

Download the entire example:

Name                           Modified     Size

examples_4_47_471_4711.tar.gz  14-Apr-2007  8.7k

Html last generated: Sun Mar 6 05:50:21 2016

Input last modified: Fri Apr 13 10:33:16 2007