Draping solvers

During manufacturing, unidirectional and woven fabric laminate plies are draped on mold surfaces which can potentially cause internal distortion of the ply fibers. When you update the layup, create zones, or export the model for solving, the draping algorithms compute the fiber orientations in the following way:

• They use a geometric approach that is independent of material properties.

• The seed curve option for primary orientation forces the warp fiber to conform to polygon or element edges.

• The geodesic orientation option launches geodesics in the primary and secondary orientations for woven fibers, and a geodesic in the primary direction for unidirectional fibers. The geodesics end at face boundaries. Depending on the complexity of the geometry, many geodesics are launched, until the whole geometry is draped.

• They compute the fiber orientations of the laminate plies based on model geometry and the options you define on the Draping Data dialog box.

• They calculate the shape of the flattened mold surfaces, creating a flat pattern for each ply. For stability, they use the 2D mesh that you create for your solution to represent the mold surface.

• They track the fiber orientation across common edges of adjoining faces even if the slopes are discontinuous.Caution: Sharp angles between faces might lead to weaknesses in the plies and manufacturing problems.

Woven solver

The woven solver computes fiber orientation for cloth woven with two sets of fibers at an angle to each other. The angle between warp (primary direction) and weft fibers is usually 90°. You select a draping start point for the calculation, and define the warp and weft fiber alignments. The woven solver accommodates distortion by changing the angle between warp and weft fibers. Because the fibers do not stretch, the angular change produces a shear distortion.

The following graphic illustrates shear angle distortion on a piece of fabric with a weft fiber angle of 90°. The lengths of the warp and weft fibers, represented by 1 and 2, do not change, but the yarn angle (3) between them does.

The shear angle is the difference between the original yarn angle and the distorted yarn angle. If the shear angle becomes too large for the characteristics of the fabric, the ply begins to wrinkle or bridge from the surface. The specified lock angle defines the maximum allowable shear angle. Elements that have a shear angle that approaches or exceeds the specified lock angle are identified by color-coded arrows when you use the View Fiber Orientations command. You can solve shearing problems by repositioning the draping start point, by splicing the ply, or by using one or more cut curves to model darts in the ply.

Unidirectional solver

The unidirectional solver models draping for plies in which all the fibers are aligned in one direction. When the material is draped, neighboring fibers of the material may slide relative to one another to some extent while maintaining the same spacing relative to one another.

The following graphic illustrates unidirectional ply draping of a piece of fabric with the fiber alignment represented by the vectors. The length and width do not change.

The shear angle (1) is a measure of fiber slippage. The unidirectional ply lock angle is a material property that specifies the maximum amount of slippage that the fibers can withstand. Elements that have a shear angle that approaches or exceeds the specified lock angle are identified by color-coded arrows when you use the View Fiber Orientations command. You can solve shearing problems by repositioning the draping start point, or by using one or more cut curves to model darts in the ply.

Projection solver

The projection solver projects the material orientation or the x-axis of a selected coordinate system onto each element. The material orientation becomes the 0° direction. This option ignores the effects of fiber distortion. When you use the View Fiber Orientations command, the fiber orientation that is shown is calculated from rotating the material orientation vector around the element’s normal by the ply angle. You can define a starting point to ensure that the fiber orientation is continuous when element normals are inconsistent.

Warning:

When you set the 2D mesh material orientation to Inherited from Layup, make sure that the material orientation of the layups is not defined by a ply using the Projection draping solver option.

Inherited from Material

The software inherits the draping solver from the type you specified on the Laminate page of the Orthotropic Material dialog box.

How do I

Define draping data for global plies

Compute draping and flat patterns

Map draped fiber orientation to material orientation

View ply fiber orientation

Change the color spectrum for the fiber orientation display

Export draping results

Learn more

Fiber orientation

List draping results

Ply-based workflow

Defining plies and a stacking sequence

Look up more details

Fiber alignment methods

Developable and undevelopable surfaces

Draping solver feedback

Computing draped fiber orientation and flat patterns

Right-click commands for global layup nodes

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

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Draping solvers, Simcenter 3D 2021.1 Series

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