SOLID95 Element Description

SOLID95 is a higher-order version of the 3D 8-node solid element SOLID45. It can tolerate irregular shapes without as much loss of accuracy. SOLID95 elements have compatible displacement shapes and are well suited to model curved boundaries.

The element is defined by 20 nodes having three degrees of freedom per node: translations in the nodal x, y, and z directions. The element may have any spatial orientation. SOLID95 has plasticity, creep, stress stiffening, large deflection, and large strain capabilities. Various printout options are also available.

Figure 95.1: SOLID95 Geometry

SOLID95 Input Data

The geometry, node locations, and the coordinate system for this element are shown in Figure 95.1: SOLID95 Geometry. A prism-shaped element may be formed by defining the same node numbers for nodes K, L, and S; nodes A and B; and nodes O, P, and W. A tetrahedral-shaped element and a pyramid-shaped element may also be formed as shown in Figure 95.1: SOLID95 Geometry. A similar, but 10-node tetrahedron, element is SOLID187.

Besides the nodes, the element input data includes the orthotropic material properties. Orthotropic material directions correspond to the element coordinate directions. The element coordinate system orientation is as described in Coordinate Systems.

Element loads are described in Element Loading. Pressures may be input as surface loads on the element faces as shown by the circled numbers on Figure 95.1: SOLID95 Geometry. Positive pressures act into the element. Temperatures may be input as element body loads at the nodes. The node I temperature T(I) defaults to TUNIF. If all other temperatures are unspecified, they default to T(I). If all corner node temperatures are specified, each midside node temperature defaults to the average temperature of its adjacent corner nodes. For any other input temperature pattern, unspecified temperatures default to TUNIF.

A lumped mass matrix formulation, which may be useful for certain analyses, may be obtained with LUMPM. While the consistent matrix gives good results for most applications, the lumped matrix may give better results with reduced analyses using Guyan reduction. The KEYOPT(5) and (6) parameters provide various element printout options (see Element Solution).

You cannot set initial state conditions (INISTATE) using this element. You can set initial state conditions using current-technology elements only (such as LINK180,SHELL181). To continue using initial state conditions in future releases, consider using a current element technology. For more information, see Legacy vs. Current Element Technologies in the Element Reference. For more information about setting initial state values, see the INISTATE command documentation and Initial State Loading in the Basic Analysis Guide.

If an unsymmetric matrix is needed for pressure load stiffness effects, use NROPT,UNSYM.

A summary of the element input is given in "SOLID95 Input Summary". A general description of element input is given in Element Input.

SOLID95 Output Data

The solution output associated with the element is in two forms:

Several items are illustrated in Figure 95.2: SOLID95 Stress Output.

The element stress directions are parallel to the element coordinate system. The surface stress outputs are in the surface coordinate systems and are available for any face (KEYOPT(6)). The coordinate systems for faces I-J-N-M and K-L-P-O are shown in Figure 95.2: SOLID95 Stress Output. The other surface coordinate systems follow similar orientations as indicated by the pressure face node description. Surface printout is valid only if the conditions described in Element Solution are met. The SXY component is the in-plane shear stress on that face. A general description of solution output is given in Solution Output. See the Basic Analysis Guide for ways to view results.

Figure 95.2: SOLID95 Stress Output

The Element Output Definitions table uses the following notation:

A colon (:) in the Name column indicates that the item can be accessed by the Component Name method (ETABLE, ESOL). The O column indicates the availability of the items in the file jobname.out. The R column indicates the availability of the items in the results file.

In either the O or R columns, “Y” indicates that the item is always available, a letter or number refers to a table footnote that describes when the item is conditionally available, and “-” indicates that the item is not available.

Table 95.3: SOLID95 Item and Sequence Numbers lists output available through the ETABLE command using the Sequence Number method. See The General Postprocessor (POST1) in the Basic Analysis Guide and The Item and Sequence Number Table in this manual for more information. The following notation is used in Table 95.3: SOLID95 Item and Sequence Numbers:

See Surface Solution for the item and sequence numbers for surface output for the ETABLE command.

SOLID95 Assumptions and Restrictions

SOLID95 Product Restrictions

When used in the product(s) listed below, the stated product-specific restrictions apply to this element in addition to the general assumptions and restrictions given in the previous section.

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