hexa8, penta6, tetra4, and other 3D volumes

hexa8, penta6, tetra4, and other 3D volumes#

Purpose

Topology holders for 3D volume elements.

Description

The hexa8 hexa20 hexa27, penta6 penta15 tetra4 and tetra10 elements are standard topology reference for 3D volume FEM problems.

In a model description matrix, element property rows for hexa8 and hexa20 elements follow the standard format with no element property used. The generic format for an element containing i nodes is [n1 ... ni MatID ProId EltId]. For example, the hexa8 format is [n1 n2 n3 n4 n5 n6 n7 n8 MatID ProId EltId].

These elements only define topologies, the nature of the problem to be solved should be specified using a property entry, see section 6.1 for supported problems and p_solid, p_heat, ... for formats.

Integration rules for various topologies are described under integrules. Vertex coordinates of the reference element can be found using an integrules command containing the name of the element such as r1=integrules('q4p');r1.xi.

Backward compatibility note : if no element property entry is defined, or with a p_solid entry with the integration rule set to zero, the element defaults to the historical 3D mechanic elements described in section 7.19.2.