Example 4712: Error estimation for L-shaped problem using patch fitting and biquadratic elements

A linear elastic plane stress problem is solved on an L-shaped domain using biquadratic
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_4712 An error estimation problem

FEM
FEM define parameters;r;L;example

FEM define nodes;r;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 1,37,8,15,22,29,33,74,86,98,110,116,122 as left_edge
FEM group nodes 7,128,14,129,21,130,28 as right_edge
FEM group nodes 37,71,38,72,39,73,40 as top
FEM define initial;r;example
FEM draw reactions
FEM draw nodes
FEM define solve;r;example
FEM solve
FEM hide nodes
FEM hide elements
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..133 basis 2
FEM update gauss stress reference components
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_4712.com         20-Nov-2001  1.2k
l.ipbase                 10-Apr-2000  2.2k
l.ipelem                 10-Apr-2000  9.8k
l.ipelfb                 10-Apr-2000  4.2k
l.ipelfd                 10-Apr-2000  8.0k
l.ipequa                 26-May-2003  1.8k
l.ipfiel                 10-Apr-2000   27k
l.ipfit                  10-Apr-2000  620 
l.ipinit                 10-Apr-2000  808 
l.ipmate                 10-Apr-2000  1.4k
l.ipnode                 10-Apr-2000   20k
l.ippara                 12-Nov-2002  5.9k
l.ipsolv                 13-Apr-2007  1.6k
readme                   10-Apr-2000  126 
reduced_integration.rgb  10-Apr-2000  288k
test_output              10-Apr-2000   43 

Download the entire example:

Name                           Modified     Size

examples_4_47_471_4712.tar.gz  14-Apr-2007   40k

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

Input last modified: Fri Apr 13 10:33:18 2007