Three Ansys Tables

The properties of each element are described in three tables of the preprocessor, /PREP7 section:

ET, the Element Types
R, the Real constants
MP, the Material Properties

The ET (element type) command: One or more element types must be selected from a list of over 100. The ET command has at least two options separated by commas. The first number is the position in the Element-Type table. It starts with 1 and is referenced by the TYPE command. The second option selects the type of element. We will use type 1, 3, 8, 10, 16, 32, 34, 42, 55, 68, 82, and 93. The element-type statements look like this:

        ET,1,Link1    ! 2D spar, Lesson 6, trusses
        ET,1,Beam3    ! 2D elastic beam
        ET,1,Link8    ! 3D spar, Lesson 6, trusses
        ET,2,Link10   ! 3D Tension-only spar, Lesson 6, trusses
        ET,1,Pipe16   ! Elastic straight pipe, Axial 1
        ET,2,Link32   ! 2D thermal conduction bar
        ET,1,Link34   ! Thermal convection link
        ET,1,Plane42  ! 2D, 4-node structural solid, Lesson 4, axisymmetric cylinder
        ET,1,Plane55  ! 2D, 4-node thermal solid, Lesson 5, temperature in a 2D plate
        ET,1,Link68   ! Thermal-electrical line element
        ET,1,Plane82  ! 2D, 8-node structural solid, Lesson 9, stressed plate with hole
        ET,1,Shell93  ! 8-node structural shell Lesson 3, Ansys graphics mode

The R (real) command: The real constants specify extensive properties such as area, diameter, wall thickness, moment of inertia, and electrical conductance for each element type. Of course, the appropriate constants change from one element type to another. The R command has at least two options. Like the ET command, the first number is the position in the Real table and is referenced by the REAL command. The remaining options give the extensive properties. The meaning of these options depends on the element type. The real statements look like this:
```
        pi = 4*atan(1)     ! Define pi symbol
        dia2 = 0.5         ! Define dia symbol
        R,1,(pi/4*dia2**2) ! Cross-sectional area for ET 1
        R,1,dia2,(dia2/2)  ! OD and wall thickness for ET 16
        R,1,9.1,110,8      ! Area, Iz, height for beam ET 3
        R,3,(SQRT(2)/3)    ! Length / resistance for ET 68
```
Notice that mathematical operations such as (SQRT(2)/3) are allowed. Furthermore, you can also define constants such as pi and dia. Note: there is one R statement for each different property, not one for each element. For example, if R defines cross sectional area, and several elements have the same area, use only one R. Then define those elements after the corresponding REAL statement.
The MP (material property) command: The material properties statements specify intensive properties such as Young's modulus, shear modulus, poisson's ratio, density, thermal expansion coefficient, thermal conductivity, convection coefficient, and electrical resistivity according to the element type. The MP command has at least three options. The first specifies the type of property and the second is the position in the Material-Property table and is referenced by the MAT command. The third option gives the intensive value. The MP command looks like this:
```
        MP,EX,1,30e6      ! elastic modulus, steel
        MP,GXY,1,11.2E6   ! shear modulus, steel
        MP,DENS,1,0.284   ! mass density, steel lbs/cu in
        MP,HF,1,2         ! convection or film coefficient
        MP,KXX,2,0.5      ! thermal conductivity, concrete 
        MP,ALPX,1,11.7e-6 ! thermal expansion coeff, steel
        MP,RSVX,1,1       ! electrical resistivity
```

MENG 421 | Lectures | Source Program -- Nodes and Elements -- Element-Property Tables -- Ansys index | Class assignments