B2000++ Glossary
- DOF
The “Degrees Of Freedom”, i.e the vector of unknowns \(x\) of the problem \(K x = b\), where \(K\) is the global system matrix (“second variation”) and \(r\) the right-hand-side (RHS) vector.
- DOF Field
A Node Field containing the “Degrees Of Freedom”. It consists of a rectangular array of
nn
rows andndof
columns,nn
being the number of mesh nodes andndof
the number of DOFs. Examples of DOF fields are displacements in solid mechanics or temperatures in heat conduction problems. The field’sTYPE
attribute isNODE
and theDOMAIN
attribute isDOF
(if defined) [1].
- NBC Field
An indexed field defining the “natural” boundary conditions, such as forces or heat. The index is either the node or the element identifier. The field’s
DOMAIN
attribute depends of the domain, as does theTYPE
attribute.
- Gradients
Gradients (element gradients) are element-wise defined DOF field derivatives and stored in sampling point fields data structures.
- EBC Field
An indexed field defining the “essential” boundary conditions, such as “zero constraints”. The index is either the node or the element identifier. The field’s
DOMAIN
attribute depends of the domain, as does theTYPE
attribute.
- NODE Field
A field defined at the mesh nodes. It consists of a rectangular array of
nn
rows andncol
columns,nn
being the number of mesh nodes andncol
the number of columns. Examples of node fields are mesh coordinates, displacements in solid mechanics or temperatures in heat conduction problems. The field’sTYPE
attribute isNODE
and theDOMAIN
attribute isDOF
(if defined).[#domain]_.
- RESIDUUM Field
The RESIDUUM field is \(K x - b\), augmented by the boundary conditions and it is usually defined at the mesh nodes. It consists of a rectangular array of
nn
rows andndof
columns,nn
being the number of mesh nodes andndof
the number of DOFs. Examples of residuum fields are reaction forcesRCFO
) in solid mechanics or the residual heat (RHEAT
) in heat conduction problems.The field’sTYPE
attribute isNODE
and theDOMAIN
attribute isDOF
(if defined).[#domain]_.
- RHS Field
The RHS “right hand sides” field \(b\) of the problem \(K x = b\). The RHS field is usually defined at the mesh nodes and consists of a rectangular array of
nn
rows andndof
columns,nn
being the number of mesh nodes andndof
the number of DOFs. Examples of right hand side fields are forces in solid mechanics (FORC
) or the external heat (HEAT
) in heat conduction problems. The field’sTYPE
attribute isNODE
and theDOMAIN
attribute isDOF
(if defined).[#domain]_.
- SPF Field
The “Sampling Point” field, usually defined element-wise for a given number of sampling points of the same kind [3], such as stresses, strains, element forces and moments, heat flow, heat capacity etc. Sampling points are usually element integration points. A SPF field is stored on the database with the AT (Array Table) data structure [2]. The field’s
DOMAIN
attribute isFIELD-SAMPLING
(theTYPE
attribute is not defined).
Footnotes