Ply Types

The specific behavior and product of a ply can be specified using Ply Type. The selection of the ply type will manipulate the behavior of a given type such that spatial effects like variation in thickness, orientation, or number of tows at a given point are abstracted to the drape table. This allows you to focus on higher level nominal ply data like material, orientation, thickness, and shape.

Type	Description
Core	Spatial changes in thickness are managed through the assigned drape table. Typically, the nominal ply thickness is the full core thickness and ramps are captured in the drape table as factors less than 1.0. The spatial changes can be defined manually by solid geometry creation in HyperMesh or imported from CAD as solid geometry. Upon ply realization with this ply type, the thickness data will be mapped to the drape table.
Homogenized Weave	The homogenized weave ply type is used to model fabrics where the scale of the material is homogenized through the thickness of the ply: the warp and weft tows are homogenized such that E1=E2. If this ply type is draped, it will automatically be converted to a Unidirectional Weave ply type, as the material properties of the full ply will become a new anisotropic material based on the new non-nominal scissoring angle between the warp and weft tows. Figure 1.
Shell to Solid Layer Divider	Used to specify number of layered solid elements generated in shell to solid conversion. Its placement in a laminate also organizes the plies in each solid layer. For example, a laminate with a stacking sequence of [ply1/ply2/dummy ply/ply3/ply4] would generate 2 layered solid elements where the first property contains [ply1/ply2] and the second property contains [ply3/ply4].
Unidirectional	Unidirectional is the default ply type. Unlike other ply types, no additional spatial corrections need to be made in the drape table to capture the details of this product.
Unidirectional Weave	The unidirectional weave is used to model fabrics where the scale of the assigned material is equivalent to the warp/weft tows which make up the woven product. The weave is modeled as four slices where each slice is 0.25x thickness of the full ply, and slice1=warp1, slice2=weft1, slice3=weft2, slice4=warp2. Four slices are used so that the ply’s stiffness is symmetric. Figure 2.
Wound	The wound ply type is used to model parts manufactured using filament winding. It is defined such that one ply in HyperMesh is equivalent to one winding layer of a given winding angle. The details of the spatially varying thickness, orientation, and number of tows passing a given element are handled in the drape table. Wound model data is obtained from manufacturing simulation. It should be imported using OptiStruct’s ply-based .fem data format. Note: This ply type cannot be draped in HyperMesh; the spatial variation of thickness and orientation is determined by external manufacturing simulation.