SOLID98 Element Description

SOLID98 is a 10-node tetrahedral version of the 8-node SOLID5 element. The element has a quadratic displacement behavior and is well suited to model irregular meshes (such as produced from various CAD/CAM systems). When used in structural and piezoelectric analyses, SOLID98 has large deflection and stress stiffening capabilities.

The element is defined by ten nodes with up to six degrees of freedom at each node (see KEYOPT(1)). See SOLID98 in the Mechanical APDL Theory Reference for more details about this element. The 3D magnetic, thermal, electric, piezoelectric, and structural field capability is similar to that described for SOLID5.

Figure 98.1: SOLID98 Geometry

SOLID98 Input Data

The geometry, node locations, and the coordinate system for this element are shown in Figure 98.1: SOLID98 Geometry. The element input data is essentially the same as for SOLID5 except that there are 10 nodes instead of 8.

Various combinations of nodal loading are available for this element (depending upon the KEYOPT(1) value). Nodal loads are defined with the D and the F commands. With the D command, the Lab variable corresponds to the degree of freedom (UX, UY, UZ, TEMP, VOLT, MAG) and VALUE corresponds to the value (displacements, temperature, voltage, scalar magnetic potential). With the F command, the Lab variable corresponds to the force (FX, FY, FZ, HEAT, AMPS, FLUX) and VALUE corresponds to the value (force, heat flow, current or charge, magnetic flux). Nonlinear magnetic B-H, piezoelectric, and anisotropic elastic properties are entered via the TB command. Nonlinear orthotropic magnetic properties can be specified with a combination of a B-H curve and linear relative permeability. The B-H curve is used in each element coordinate direction where a zero value of relative permeability is specified. Only one B-H curve can be specified per material.

Element loads are described in Element Loading. Pressure, convection or heat flux (but not both), radiation, and Maxwell force flags may be input on the element faces indicated by the circled numbers in Figure 98.1: SOLID98 Geometry using the SF and SFE commands. Positive pressures act into the element. Surfaces at which magnetic forces are to be calculated may be identified by using the MXWF label on the surface load commands (no value is required.) A Maxwell stress tensor calculation is performed at these surfaces to obtain the magnetic forces. These forces are applied in solution as structural loads. The surface flag should be applied to "air" elements adjacent to the body for which forces are required. Deleting the MXWF specification removes the flag.

The body loads temperature, heat generation rate, and magnetic virtual displacement may be input based on their value at the element's nodes or as a single element value (BF and BFE). When the temperature degree of freedom is active (KEYOPT(1) = 0, 1 or 8), applied body force temperatures (BF, BFE) are ignored. In general, unspecified nodal values of temperatures and heat generation rate default to the uniform value specified with the BFUNIF or TUNIF commands. Calculated Joule heating (JHEAT) is applied in subsequent iterations as heat generation rate loading.

If the temperature degree of freedom is present, the calculated temperatures override any input nodal temperatures.

Air elements in which Local Jacobian forces are to be calculated may be identified by using nodal values of 1 and 0 for the MVDI label (BF). See the Low-Frequency Electromagnetic Analysis Guide for details. These forces are not applied in solution as structural loads.

A summary of the element input is given in "SOLID98 Input Summary". A general description of element input is given in Element Input.

SOLID98 Output Data

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

Several items are illustrated in Figure 98.2: SOLID98 Element Output. The component output directions are parallel to the element coordinate system. The reaction forces, heat flow, current, and magnetic flux at the nodes can be printed with the OUTPR command. A general description of solution output is given in Solution Output. See the Basic Analysis Guide for ways to view results.

Figure 98.2: SOLID98 Element 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 98.3: SOLID98 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 reference for more information. The following notation is used in Table 98.3: SOLID98 Item and Sequence Numbers:

SOLID98 Assumptions and Restrictions

SOLID98 Product Restrictions

There are no product-specific restrictions for this element.