Page 40 - Using ANSYS for Finite Element Analysis Dynamic, Probabilistic, Design and Heat Transfer Analysis

composite materials • 27
SOLID191. Which element you choose depends on the application, the
type of results that need to be calculated, and so on. Check the individ-
ual element descriptions to determine if a specific element can be used
in your ANSYS product. All layered elements allow failure criterion
calculations.

2.2.1.1 SheLL99—Linear Layered Structural Shell element

SHELL99 is an 8-node, 3-D shell element with six degrees of freedom
at each node. It is designed to model thin to moderately thick plate and
shell structures with a side-to-thickness ratio of roughly 10 or greater.
For structures with smaller ratios, you may consider using SOLID46.
The SHELL99 element allows a total of 250 uniform-thickness layers.
Alternately, the element allows 125 layers with thicknesses that may vary
bilinearly over the area of the layer. If more than 250 layers are required,
you can input your own material matrix. It also has an option to offset the
nodes to the top or bottom surface.

2.2.1.2 SheLL91—nonlinear Layered Structural Shell element

SHELL91 is similar to SHELL99 except that it allows only up to 100
layers and does not allow you to input a material property matrix. How-
ever, SHELL91 supports plasticity, large-strain behavior, and a special
sandwich option, whereas SHELL99 does not. SHELL91 is also more
robust for large deflection behavior.

2.2.1.3 SheLL181—Finite Strain Shell

SHELL181 is a 4-node 3-D shell element with six degrees of freedom
at each node. The element has full nonlinear capabilities including large
strain and allows 255 layers. The layer information is input using the
section commands rather than real constants. Failure criteria is available
using the FC commands.

2.2.1.4 SoLiD46—3-D Layered Structural Solid element

SOLID46 is a layered version of the 8-node, 3-D solid element,
SOLID45, with three degrees of freedom per node (UX, UY, UZ). It is
designed to model thick-layered shells or layered solids and allows up to