Extract nodes and elements from abaqus input file to matlab

Hello,

I have an abaqus input file with the following structure:

Now I want to extract the nodes and elements to matlab in order to do computations there. I have two problems:

• The nodes of each elements are written in 2 lines. How can I change this to one line without joining each line individually?
• Whats in general the easiest and fastest way to read this out?

Thanks

Answer 1

[KSSV]

clc; clear all ;
fname = 'example.txt' ;
fid = fopen(fname,'rt') ;
S = textscan(fid,'%s','Delimiter','\n');
S = S{1} ;
%%Get the line number of mises 
idxS = strfind(S, 'Node');
idx1 = find(not(cellfun('isempty', idxS)));
idxS = strfind(S, 'Element');
idx2 = find(not(cellfun('isempty', idxS)));
idxS = strfind(S, 'End');
idx3 = find(not(cellfun('isempty', idxS)));
% pick  nodes 
nodes = S(idx1+1:idx2-1) ;
nodes = cell2mat(cellfun(@str2num,nodes,'UniformOutput',false)) 
% pick elements 
elements = S(idx2+1:idx3(1)-1) ;
count = 0 ;
ele = cell(length(elements)/2,1) ;
for i = 1:2:length(elements)
    count = count+1 ;
    ele{count,1} = [elements{i} elements{i+1}];
end
ele = cell2mat(cellfun(@str2num,ele,'UniformOutput',false))

[Daniel Heilmann]

Thank you very much! I testet the code and it is exactly what I was looking for!

[Callum]

A way to speed this up is to use the first half of the code (up to idx3), then use dlmread with the idx values as row offsets to read in numerical data. It's a bit ugly, but it's much faster (especially if you have millions of nodes/elements). Just put (after line 12)

nodes = dlmread(fname,',',[idx1,0,idx2-2,2]);
elements = dlmread(fname,',',[idx2,0,idx3(1)-2,3]);

Not sure this gives exactly the same output (I was too impatient to let the original run out) but it gets you node and element info.

Answer 2

[KSSV]

doc textscan

Answer 3

[Praveen Venkatesh Sethumadhavan Vasan]

Dear KSSV,

ele = cell2mat(cellfun(@str2num,elements,'UniformOutput',false)); is this correct without loop?

I didnt understand why you used loop at the end.