Example 7171: Homogeneous isotropic membrane.

Estimate c1 & c2 with 2 load sets. 48 element rubber membrane from biaxial rig.


The comfile run by this example is as follows:

#PJH 30Jun1998
#Material parameter fitting by least squares (fit c1 & c2 parameters).
#A 48 element membrane is read in with two sets of coords & loads.
#Note: Smoothing terms are included in the fit.

FEM de node;r;mesh;example             #69 nodes
FEM de base;r;mesh;example             #bilinear
FEM de elem;r;mesh;example             #48 elements
FEM de fibr;d
FEM de elem;d fibre
FEM de wind
FEM dr line
refresh graphics

FEM de equa;r;mesh;example             #finite elasticity membrane
FEM de mate;r;mesh;example             #Mooney-Rivlin c1=1, c2=0.2 both node based
FEM de init;d                          #initial conditions

#FEM de opt;r;test;example             !1 param only in fit
#FEM eval resid with 1,1,1,1,0.2,0.2,0.2,0.2 !correct values, so resids=0
#FEM eval resid num_deriv              !gives RESJAC matrix (#resids x #params)

FEM de field;r;mesh;example            #setup field variable for material param fit
FEM de elem;r;mesh;example field

FEM de fit;r;mesh;example material resid #define fit for matl params to residuals
#----------------------------data set 2--------------------------------
FEM de node;r;coord2;example dep 11 nc 1 #read in deformed coords to YP(ny,1)
FEM de node;r;force2;example dep 11 nc 2 #read in nodal forces to YP(ny+NYT,1)
FEM dr reac iy=11 nc=2 scale 50        #shows bdry forces
refresh graphics
#----------------------------data set 5--------------------------------
FEM de node;r;coord5;example dep 12 nc 1 #read in deformed coords to YP(ny,1)
FEM de node;r;force5;example dep 12 nc 2 #read in nodal forces to YP(ny+NYT,1)
FEM dr reac iy=12 nc=2 scale 50        #shows bdry forces
refresh graphics
#----------------------------data set 9--------------------------------
FEM de node;r;coord9;example dep 13 nc 1 #read in deformed coords to YP(ny,1)
FEM de node;r;force9;example dep 13 nc 2 #read in nodal forces to YP(ny+NYT,1)
FEM dr reac iy=13 nc=2 scale 50        #shows bdry forces
refresh graphics
#------------------ -------fit mat.l params----------------------------
FEM fit   #least-squares fit of material params to nodal residuals
#----------------------show forces on deformed mesh--------------------
FEM dr line def rgb=blue
FEM dr reac iy=13 nc=2 scale 50        #shows bdry forces
refresh graphics
#----------------------draw mat.l parameter field----------------------
FEM up field from material to 1 using fit CP 2
FEM up field from material to 2 using fit CP 3
FEM dr field deformed field 1
FEM dr contour field 1 label off
refresh graphics
#----------------------------------------------------------------------

FEM list mate using solve #list original material parameters  (c1=1,c2=0.2)
FEM list mate using fit   #list fitted material parameters (c1,c2 at 4 nodes)
#FEM dr strain scale 20 


Files used by this example are:

Name              Modified     Size

example_7171.com 10-Apr-2000 2.7k coord2.ipnode 10-Apr-2000 10k coord5.ipnode 10-Apr-2000 10k coord9.ipnode 10-Apr-2000 10k force0.ipnode 10-Apr-2000 8.2k force2.ipnode 10-Apr-2000 8.2k force5.ipnode 10-Apr-2000 8.2k force9.ipnode 10-Apr-2000 8.2k membrane1.gif 10-Apr-2000 41k membrane1.ps 10-Apr-2000 2.1M membrane2.gif 10-Apr-2000 52k membrane2.ps 10-Apr-2000 2.3M membrane3.gif 10-Apr-2000 39k membrane3.ps 10-Apr-2000 2.1M membrane4.gif 10-Apr-2000 37k membrane4.ps 10-Apr-2000 2.1M mesh.ipbase 10-Apr-2000 2.0k mesh.ipelem 10-Apr-2000 12k mesh.ipelfd 10-Apr-2000 10k mesh.ipequa 02-May-2004 1.8k mesh.ipfiel 10-Apr-2000 10k mesh.ipfit 13-Apr-2007 1.6k mesh.ipmate 10-Apr-2000 2.4k mesh.ipnode 10-Apr-2000 8.5k

Download the entire example:

Name                           Modified     Size

examples_7_71_717_7171.tar.gz 14-Apr-2007 1.2M

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

Input last modified: Fri Apr 13 10:35:49 2007


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