ROXIE/BEM-FEM Transfer Files

The HMO-file

The .hmo-file contains mesh information. It is produced by either the HERMES 2-D parametric mesh generator or by the HyperMesh, 3-D mesh generator, using the edyson template file, edyson_tech_doc.

The .hmo-file consists of six blocks: The first block contains component information (material names, coils), the second block contains load collector data, the third block vector collector information, the fourth block specifies all nodes, the fifth one the elements, and the last one additional boundary conditions. With ROXIE we only make use of blocks one, four and five which we will describe in detail in the following tables. The .hmo-file is organized as follows:

    `BEG_COMP_DATA`
    `...`
    `END_COMP_DATA`
    `BEG_NODL_DATA`
    `...`
    `END_NODL_DATA`
    `BEG_ELEM_DATA`
    `...`
    `END_ELEM_DATA`

The component data

The body of the component collector data block is structured as follows. One header record

Variable	Type	Description
`NCOLL`	I8	Total number of components

A sequence of records with the component numbers and names

Variable	Type	Description
`ICOLL`	I8	Number of the component
n/a	String	Component name

For numerical calculations the last component must have the name SuperCoils. It represents the coils modelled by line-currents.

The nodal data

The body of the component data block is structured as follows. One header record

Variable	Type	Description
`NNT`	I8	Total number of nodes

A sequence of records with the component numbers and names

Variable	Type	Description
`IN_HMO`	I8	Number of the node
XYZ(3)	1X,F12.8	Coordinates

For BEMFEM-calculations the node numbers have to be in ascending order. For EDYSON they are only required to be unique. The coordinates are given in mm. Axisymmetric problems are discretized in the xy-plane.

Element data

The body of the element data block is structured as follows. One header record

Type	Description
I8	Total number of all elements in file
1X,I8	Total number of L2 elements
1X,I8	Total number of L3 elements
1X,I8	Total number of T3 elements
1X,I8	Total number of T6 elements
1X,I8	Total number of Q4 elements
1X,I8	Total number of Q8 elements
1X,I8	Total number of TH4 elements
1X,I8	Total number of TH10 elements
1X,I8	Total number of P6 elements
1X,I8	Total number of P15 elements
1X,I8	Total number of H8 elements
1X,I8	Total number of H20 elements

A sequence of records which describe theelements

Variable	Type	Description
`IEL_HMO`	I8	Number of the element
`ICOLL`	1X,I4	Element component number
`ICONF`	1X,I3	Element config number
`KNE(1)`	1X,I8	Number of the first node
`KNE(2)`	1X,I8	Number of the second node
...	...	...

For BEMFEM-calculations the element numbers have to be in ascending order. For EDYSON they are only required to be unique. The element component number describes which material the element belongs to. The material names are given in the component data block. The element type number ICONF describes the element geometry as follows:

`ICONF`	Type	Description
60	L2	Line element with two nodes
63	L3	Line element with three nodes
103	T3	Triangular element with three nodes
106	T6	Triangular element with six nodes
104	Q4	Quadrilateral element with four nodes
108	Q8	Quadrilateral element with eight nodes
204	TH4	Tetrahedral element with four nodes
210	TH10	Tetrahedral element with ten nodes
206	P6	Pentahedral element with six nodes
215	P15	Pentahedral element with fifteen nodes
208	H8	Hexahedral element with eight nodes
220	H20	Hexahedral element with twenty nodes

With ROXIE we only use element types T6, Q8, P15 and H20. The element-wise node numbering of the respective types is depicted in Fig. 16.1.

Fig. 16.1: sFinite-element types used with ROXIE. Element-wise node numbering in the *.hmo*-file.

The COR file

The .cor-file specifies the nodal coordinates for BEMFEM. It is basically a reference for the renumbering of the .hmo-file nodes. The first line is a header info line (version number, etc.). Then follows the header data line:

Variable	Type	Description
`NNT`	I8	Total number of nodes
`NDLN`	I7	Number of degrees of freedom per node
`NDIM`	I6	Dimension of the problem

Then comes a sequence of records of the form:

Variable	Type	Description
`IN`	Integer	Node number
`XYZ(3)`	Double	Nodal coordinates
`BSECT`	Integer	Boundary section (0:Interior FEM node, >`<!-- -->`0: BEM node on given boundary section)
`IDOF`	Integer	Number of degrees of freedom for current node

The last line is the closing line:

Variable	Type	Description
`FILEEND`	Integer	`FILEEND=-1` denotes the end of the file

The following table summarizes the different coordinate systems for the respective problem types:

Geometry	(x_1,x_2,x_3)
Plain 2-D	(x,y,0)
Axisymmetric	(r,0,z) (z,r,0)
3-D	(x,y,z)

The ELE file

The .ele-file contains elemental data. It has one header line (version number, etc.) and one data header line:

Variable	Type	Description
`IELEMS`	Integer	Total number of elements including boundary elements
`IMAXNOD`	Integer	Maximum number of nodes per element

It follows a sequence of element records:

Variable	Type	Description
`IEL`	Integer	Element number
`ITPE`	Integer	Element type number
`ICOLL`	Integer	Collector- (component-) number to which the element belongs
`INODS(21)`	Integer	A sequence of node numbers from .cor-file for the current element terminated by 0

A file closing line

Variable	Type	Description
`FILEEND`	Integer	`FILEEND = -1` denotes the end of the file

The BDR file

The boundary condition data is given in the .bdr-file. One file header info line (with version number, etc.) is followed by a sequence of records of the form

Variable	Type	Description
`INOD`	Integer	Node number (.cor-file) at which a boundary condition (BC) is specified
`IDOFTYP(10))`	0X,I1	Sequence of 10 flags each of which specifies a type of BC for each degree of freedom in the node; flag 0 means: no BC specified 1: homogeneous Dirichlet-condition 2: inhomogeneous Dirichlt-condition 4: pseudo-BEM-nodes for subsequent field calculation 5: inhomogeneity BEM-node 8: positive periodic condition 9: negative periodic condition
`VCOND(10)`	1X,12.5	Sequence of BC vallues for each degree of freedom

A file closing line

Variable	Type	Description
`FILEEND`	Integer	`FILEEND = -1` denotes the end of the file

ROXIE uses only the BC flag 1 for homogeneous Dirichlet-conditions.

The SOL file

The .sol-file contains the computed results of BEMFEM. It has one file header info line and a sequence of time steps. For ROXIE there is only one time step available. Each time step is composed of a header line:

Variable	Type	Description
`ITYP`	Integer	`ITYP = -1` marks the header line of a time step
`IPAS`	Integer	Number of the present time step
`TIME`	Double	Absolute time of the present time step

Then comes a sequence of subblocks containing problem dependent results; each subblock consists of a block header:

Variable	Type	Description
`ITYP`	Integer	`ITYP = -11` marks the block header line of the potential data block
`NCOL`	Integer	Maximum number of data columns (coordinates and/or reults)
`NROW`	Integer	Number of rows for the present block (0=not available)

The header is followed by a sequence of records:

Variable	Type	Description
`IN`	Integer	Node number
`XYZ(3)`	Double	Nodal Coordinates
`V(NCOL-3)`	Double	Results (vector and/or scalar potential)

The block is closed by a line

Variable	Type	Description
`BLOCKEND`	Integer	`BLOCKEND = -99` marks the block closing line.

And the time step is closed by

Variable	Type	Description
`TIMESTEPEND`	Integer	`TIMESTEPEND = -9` marks the end of the current time step.

The SRC file

BEM-FEM coupled problems can be driven by a source potential (φ_mathrm{S}, mathbf{A}_mathrm{S}) due to impressed charges or currents in the BEM domain. This potential should be given at the locations of the boundary nodes in the following structure. The first line yields

Variable	Type	Description
`BNODES`	I5	Number of nodes belonging to the boundary

Then follows a sequence of records with node numbers, nodal coordinates and prescribed potential values.

Variable	Type	Description
IN	I5	.cor-file node number
XYZ(3)	1X,E18.11	Coordinates
POT(3)	1X,E18.11	prescribed source potential, see below

The node numbers must be in ascending orders and the number of records must be equal BNODES. The degrees of freedom of the impressed source potential depend on the problem type as follows:

Problem Type	DOF1	DOF2	DOF3
2-D	A_z
2-D Axi-symm.	rA_φ
3-D vector Pot.	A_x	A_y	A_z
3-D scalar Pot.	φ

The EVAL.LOC file

The BEM-FEM coupling allows the evaluation of the reduced potentials and fields at arbitrary points in the BEM domain once the problem has been solved. Such additional evaluation points are given in the eval.loc-file with the following structure. The header record yields

Variable	Type	Description
`NKSI`	I5	Number of additional evaluation points
`HFD`	1X,E12.5	Parameter h for finite differences

The header is followed by a sequence of records with the coordinates of the evaluation points:

Variable	Type	Description
`I`	I5	Number of evaluation point
`V(3)`	1X,E18.11	Coordinates

The EVALBFOUT.LOC file

On exit of a BEMFEM run an output file is written that yields the potential in the additional evaluation points specified in the eval.loc-file. The header record reads:

Variable	Type	Description
`NKSI`	I5	Number of additional evaluation points

Then follows a sequence of records with the results:

Variable	Type	Description
`I`	I6	Number of the evaluation point
`V(9)`	1X,E18.11	Coordinates and result DOF, see below

The degrees of freedom that appear depend on the problem type:

Problem type	DOF1	2	3	4	5	6	7	8	9
Magnetic mathbf{A} 2-D Axi 3-D	x	y	A_z	B_x	B_y	&	&
	Axi	z	r	rA_φ	B_z	B_r	&	&
	3-D	x	y	z	A_x	A_y	A_z	B_x	B_y
Magnetic φ 3-D	x	y	z	φ	B_x	B_y	B_z	&

The mathbf{B} field is computed from the potentials by means of finite differences with the parameter HFD.

The PLOTBF.OUT file

Some results from a computation for postprocessing are written to a textfile. In 2-D, this is the plotbf.out-file. It starts with a header record

Variable	Type	Description
`NELT`	Integer	Number of finite elements

Then come the finite-element headers, each one followed by a sequence of nodal records. The element header has

Variable	Type	Description
`IEL`	I5	Number of the element as specified in the .ele-file
`INEL`	I5	Number of nodes in the element
`IGPE`	I5	Properties group number as specified in the .ele-file
`MUR`	1X,E12.5	Average relative permeability of the element

The nodal records of each element read

Variable	Type	Description
`KNOD`	I5	Internal number of the considered node (not related to .cor-file)
`XY(2)`	1X,E12.5	x-, y-coordinate
`BXY(2)`	1X,E12.5	B_x-, B_y-component
`AZ`	1X,E12.5	A_z-component

The results are total fields (sum of reduced- and source fields). For Q8 quadrilateral elements a 9th line is added with empty KNOD entry. This record contains the field and potential values in the center of the element.

The PLOTBF3-D.OUT file

The postprocessing file for 3-D calculations is somewhat differently structured than the plotbf.out-file. There is one header record

Variable	Type	Description
`RELT`	Integer	Number of boundary elements

A sequence of records for each boundary element, each one followed by a sequence of nodal records.

Variable	Type	Description
`IEL`	I5	Consecutive number of the boundary element
`INEL`	I5	Number of nodes in the element

The nodal records read

Variable	Type	Description
`KNOD`	I5	Internal number of the considered node (not related to .cor-file)
`XYZ(3)`	1X,E12.5	x-, y-, z-coordinate
`A(3)`	1X,E12.5	A_x-, A_y-, A_z-component
`B(3)`	1X,E12.5	B_x-, B_y-, B_z-component

Additional files

The following files are not further detailed in this manual:

File	Description
`.DAPA`	Magnetization curves for BEMFEM
`.dyn`	Contains integral and mechanical result quantities for each time step
`.ght`	Binary file which contains the BEM matrices of a previous run
`.inp`	BEMFEM input file
`.out`	Collects messages from a BEMFEM run