4.1
HEXAHEDRON NO.1 WITH 8 NODES
The hexahedron element
calculates deflections and stresses in space. It is a transformed
element,
therefore it can have a wedging form or another oblique-angled form.
The
transformation is isoparametric. The integration is carried out
numerically in
all three axises according to Gauss- Legendre. Thus, the integration
order can
be selected in Z88I1.TXT in
the material information lines. The order 2 is mostly sufficient.
Hexahedron
No.1 is also well usable as a thick plate element, if the plate's
thickness is
not too small against the other dimensions. The element causes high
computing
load and needs a lot of memory, because the element stiffness matrix
has the
order 24*24.
Hexahedrons No.1 can be
generated by the mesh
generator Z88N from super
elements Hexahedrons
No.10, but Hexahedron No.1
cannot be used as a super
element.
Input:
CAD (see chapter 2.7.2):
Upper plane: 1 - 2 - 3 - 4
- 1, quit LINE function
Lower plane: 5 - 6 -7 - 8 - 5, quit LINE function
1 - 5, quit LINE function
2 - 6, quit LINE function
3 - 7, quit LINE function
4 - 8, quit LINE function
Z88I1.TXT
> KFLAG for cartesian (0) or cylindrical coordinates (1)
> IQFLAG=1 if surface and pressure loads for this element are filed
in Z88I5.TXT
> 3 degrees of freedom for each node
> Element type is 1
> 8 nodes per element
> Cross-section parameter QPARA is 0 or any other value, has no
influence
> Integration order INTORD for each mat info line. 2 is usually
good.
Z88I3.TXT
> Integration order INTORD for stress calculation: Can be
different
from INTORD in Z88I1.TXT.
0 = Calculation of stresses in the corner nodes
1,2,3,4 = Calculation of stresses in the Gauss points
> any KFLAG, has no influence
> Reduced stress flag
ISFLAG:
0 = no calculation of reduced stresses
1 = von Mises stresses in the Gauss points ( INTORD not 0 !)
2 = principal stresses in the Gauss points (INTORD not 0!)
3 = Tresca stresses in the Gauss
points (INTORD not 0!)
Z88I5.TXT
This file is
optional and only used if in addition to nodal forces surface and
pressure
loads applied onto element no.1:
>
Element number with surface and pressure
load [Long]
>
Pressure, positive if poiting towards the
surface [Double]
>
Tangential shear, positive in local r
direction [Double]
>
Tangential shear, positive in local s
direction [Double]
> 4
nodes of the loaded surface [4 x Long]
The local r
direction is defined by the nodes
1-2, the local s direction is defined by the nodes 1-4. The local nodes
1, 2, 3
, 4 may differ from the local nodes 1, 2, 3, 4 used for the coincidence.
Results:
Displacements in X, Y and Z
Stresses: SIGXX, SIGYY, SIGZZ, TAUXY, TAUYZ, TAUZX, respectively
for
corner nodes or Gauss points. Optional von Mises stresses.
Nodal forces in X, Y and Z for each element and each node.