Example 712: Fitting displacement fields to speckle data

A 2D membrane undergoing biaxial stretch has a speckle pattern drawn on it. The displacement data from the speckle analysis in XVG is put in .ipdata files. The displacement data is fitted here with an fe mesh and then the displacements are added to the nodal coords to give the deformed mesh.

The comfile run by this example is as follows:

#Fit displacement fields from speckle data

fem define parameter;r;paint;example

fem define base;r;paint;example         #bilinear basis
fem define node;r;;example              #37 nodes
fem define element;r;;example           #32 elements
fem define fibre;r;;example             #fibre field is 0
fem define element;r;;example fibre     #fibre basis is 1
fem define equation;r;paint;example     #large deformation, plane stress
fem define node;r;paint;example dep 1   #put undeformed geom into YP(1)
fem define window
fem draw lines deformed rgb=blue        #draws initial mesh from YP(1)
fem define field;r;paint;example        #2 field values per node
fem define element;r;;example field     #bilinear basis
fem define data;r;paint01;example field #7436 data pts
#fem define xi;c                        !calculate element coords for data pts
#fem define xi;w;paint01                !write Xi coords (so can read next time)
fem define xi;r;paint01;example         #previously calc.d Xi coords
fem de fit;r;paint;example field      
fem fit                                 #fit displacement field
fem list node                           #show orig node coords + fitted displacements
fem update node add_lin                 #adds fitted field values to geom coords
fem draw lines                          #draw updated mesh
#fem define node;w;paint01              !write deformed coords
fem

Files used by this example are:

Name              Modified     Size

example_712.com   20-Nov-2001  1.4k
paint.ipbase      10-Apr-2000  2.0k
paint.ipelem      10-Apr-2000   22k
paint.ipelfb      10-Apr-2000  4.5k
paint.ipelfd      10-Apr-2000  6.3k
paint.ipequa      02-May-2004  1.8k
paint.ipfibr      30-Jan-2001  3.2k
paint.ipfiel      10-Apr-2000  5.6k
paint.ipfit       13-Apr-2007  6.7k
paint.ipnode      10-Apr-2000  5.3k
paint.ippara      12-Nov-2002  5.9k
paint.ippara_old  10-Apr-2000  4.4k
paint01.ipdata    10-Apr-2000  806k
paint01.ipnode    10-Apr-2000  6.0k
paint01.ipxi      10-Apr-2000  254k

Download the entire example:

Name                      Modified     Size

examples_7_71_712.tar.gz  14-Apr-2007  196k

Html last generated: Sun Mar 6 05:50:30 2016

Input last modified: Fri Apr 13 10:35:40 2007