bConverged

Eight-node brick element (C3D8 and F3D8)

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Eight-node brick element (C3D8 and F3D8)

The C3D8 element is a general purpose linear brick element, fully integrated (2x2x2 integration points). The shape functions can be found in [33]. The node numbering follows the convention of Figure 29 and the integration points are numbered according to Figure 30. This latter information is important since element variables printed with the *EL PRINT keyword are given in the integration points.

**Figure 29:** 8-node brick element
$\begin{figure}\epsfig{file=C3D8.eps,width=10cm}\end{figure}$

**Figure 30:** 2x2x2 integration point scheme in hexahedral elements
$\begin{figure}\epsfig{file=Int8.eps,width=8cm}\end{figure}$

Although the structure of the element is straightforward, it should not be used in the following situations:

due to the full integration, the element will behave badly for isochoric material behavior, i.e. for high values of Poisson's coefficient or plastic behavior.
the element tends to be too stiff in bending, e.g. for slender beams or thin plates under bending. [66].

The F3D8 element is the corresponding fluid element.

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guido dhondt 2011-03-26