FEM_IO
Read or Write a Finite Element Model

FEM_IO is a MATLAB library which reads or writes the data that defines a finite element model.

The finite element model is assumed to include three items:

• Node coordinates;
• Elements defined by a sequence of node indices;
• Node data;

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

FEM_IO is available in a C++ version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

FEM_TO_MESH, a MATLAB program which reads a pair of FEM files defining node coordinates and elements, and creates a corresponding MESH file.

FEM_TO_TEC, a MATLAB program which converts an FEM model into a TEC graphics file.

FEM1D, a data directory which contains examples of 1D FEM files, three text files that describe a 1D finite element model;

FEM2D, a data directory which contains examples of 2D FEM files, three text files that describe a 2D finite element geometry;

FEM2D_PACK, a MATLAB library which is useful for 2D finite element calculations.

FEM3D, a data directory which contains examples of 3D FEM files, three text files that describe a 3D finite element geometry;

MESH_IO, a MATLAB library which can read or write MESH files, which can be used to define the geometry of a finite element mesh in 2D or 3D, using triangles, quadrilaterals, tetrahedrons or hexahedrons.

TABLE_IO, a MATLAB library which can read and write TABLE files.

Reference:

1. Hans Rudolf Schwarz,
   Finite Element Methods,
   Academic Press, 1988,
   ISBN: 0126330107,
   LC: TA347.F5.S3313..
2. Gilbert Strang, George Fix,
   An Analysis of the Finite Element Method,
   Cambridge, 1973,
   ISBN: 096140888X,
   LC: TA335.S77.
3. Olgierd Zienkiewicz,
   The Finite Element Method,
   Sixth Edition,
   Butterworth-Heinemann, 2005,
   ISBN: 0750663200,
   LC: TA640.2.Z54
4. Daniel Zwillinger, editor,
   CRC Standard Mathematical Tables and Formulae,
   30th Edition,
   CRC Press, 1996,
   ISBN: 0-8493-2479-3.

Source Code:

• fem_read.m reads the node coordinate, element and node data files defining a finite element model.
• fem_write.m writes the node coordinate, element and node data files defining a finite element model.
• file_column_count.m counts the number of columns in a file.
• file_name_specification.m determines the names of the input files.
• file_row_count.m counts the number of rows in a file.
• i4mat_data_read.m reads the data from an I4MAT file.
• i4mat_header_read.m reads the header from an I4MAT file.
• i4mat_transpose_print.m prints an I4MAT, transposed.
• i4mat_transpose_print_some.m prints some of an I4MAT, transposed.
• i4mat_write.m writes an I4MAT file.
• r8_epsilon.m returns the machine roundoff for an R8.
• r8mat_data_read.m reads data from an R8MAT file.
• r8mat_header_read.m reads the header from an R8MAT file.
• r8mat_transpose_print.m prints an R8MAT, transposed.
• r8mat_transpose_print_some.m prints some of an R8MAT, transposed.
• r8mat_write.m writes an R8MAT file.
• s_len_trim.m returns the length of a string to the last nonblank.
• s_word_count.m counts the number of words in a line.
• timestamp.m prints the current YMDHMS date as a timestamp.

Examples and Tests:

FEM_IO_TEST is a test program which tests the routines that read and write finite element data.

• fem_io_test.m runs all the tests.
• fem_io_test01.m tests FEM_READ by reading the ELL data.
• fem_io_test02.m tests FEM_WRITE by writing the TINY data.
• fem_io_test_output.txt, the output file.

ELL is an example of a 2D finite element model in which a scalar value is stored. This data was computed by the FREE_FEM_POISSON program and is read by FEM_READ.

• ell_nodes.txt
• ell_elements.txt
• ell_values.txt

P01 is a 3D rectangular channel, with dimensions 1x1x3, using 584 nodes and 2568 elements. This data was created by DISTMESH.

• p01_nodes.txt
• p01_elements.txt
• p01_values.txt

TINY is a "tiny" example of a 2D finite element model in which a vector value is stored. This data was written by the FEM_WRITE routine.

• tiny_nodes.txt
• tiny_elements.txt
• tiny_values.txt

You can go up one level to the MATLAB source codes.