Mechanical APDL Basic Analysis Guide - Ansys

Chapter 1: Getting Started with ANSYS
• For line and area elements that require geometry data (cross-sectional area, thickness, diameter, etc.)
to be specified as real constants, you can verify the input graphically by using the following commands
in the order shown:
Command(s): /ESHAPE and EPLOT
GUI: Utility Menu> PlotCtrls> Style> Size and Shape
Utility Menu> Plot> Elements
ANSYS displays the elements as solid elements, using a rectangular cross-section for link and shell elements
and a circular cross-section for pipe elements. The cross-section proportions are determined from the real
constant values.
1.1.3.1. Creating Cross Sections
If you are building a model using BEAM188or BEAM189, you can use the section commands (SECTYPE,
SECDATA, etc.) or their GUI path equivalents to define and use cross sections in your models. See "Beam
Analysis and Cross Sections" in the Structural Analysis Guide for information on how to use the BeamTool to
create cross sections.
1.1.4. Defining Material Properties
Most element types require material properties. Depending on the application, material properties can be
linear (see Linear Material Properties (p. 4)) or nonlinear (see Nonlinear Material Properties (p. 7)).
As with element types and real constants, each set of material properties has a material reference number.
The table of material reference numbers versus material property sets is called the material table. Within
one analysis, you may have multiple material property sets (to correspond with multiple materials used in
the model). ANSYS identifies each set with a unique reference number.
While defining the elements, you point to the appropriate material reference number using the MAT command.
1.1.4.1. Linear Material Properties
Linear material properties can be constant or temperature-dependent, and isotropic or orthotropic. To define
constant material properties (either isotropic or orthotropic), use one of the following:
Command(s): MP
GUI: Main Menu> Preprocessor> Material Props> Material Models
(See Material Model Interface (p. 8) for details on the GUI.)
You also must specify the appropriate property label; for example EX, EY, EZ for Young's modulus, KXX, KYY,
KZZ for thermal conductivity, and so forth. For isotropic material you need to define only the X-direction
property; the other directions default to the X-direction value. For example:
MP,EX,1,2E11 ! Young's modulus for material ref. no. 1 is 2E11
MP,DENS,1,7800 ! Density for material ref. no. 1 is 7800
MP,KXX,1,43 ! Thermal conductivity for material ref. no 1 is 43
Besides the defaults for Y- and Z-direction properties (which default to the X-direction properties), other
material property defaults are built in to reduce the amount of input. For example, Poisson's ratio (NUXY)
defaults to 0.3, shear modulus (GXY) defaults to EX/2(1+NUXY)), and emissivity (EMIS) defaults to 1.0. See
the Element Reference for details.
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