Reply To: ACP – Element coordinate system, draping

[Sean Harvey]

,nFor the first answer, the shell element will have it's normal pointed outward automatically, so the x-y directions will be inplane to the shell and follow the curvature. But for orthotropic materials, the in -plane orientation is typically critical since the moduli can vary (x vs y). This is where ACP will allow you to setup the rosettes, draping, etc. to get the orientations correct. For a simple flat plate, one may not need ACP, but for general composite structures, it becomes key.nRegarding the draping nWhen we specify a rosette and the reference direction follows the x direction of the rosette, this works for simple surfaces. Like a plate, box, etc. But for general complex surfaces, if you actually lay down a fabric, the orientations will shear based on the shape. Notice when a fabric is put on a sphere, the mesh shears. So in the image below, the blue shows very little shearing at the top of the sphere (I set this as the seed point). But notice as I get further away, to make the fabric conform to the sphere, the fabric will shear. This means that the fiber orientation will change.nnSo, when you turn on internal draping by setting to internal draping, it computes this effect. It takes computational resources to calculate this so keep that in mind when doing for many plies. If you leave as no draping, then the rosette is projected onto the surface, and you can look at the reference direction arrows in ACP to show what that looks like.nDraping for a specific material can also be assigned to an Oriented Selection Set (OSS). In that case, the Reference Direction of the OSS is adjusted. All associated modeling plies use this draped reference direction. This avoids running multiple draping simulations on the same surface. If Internal Draping is applied to a modeling ply associated with a draped OSS then the OSS’s draped Reference Direction is ignored and an independent draping simulation is started for the Modeling Ply.nDoes that answer your questions? Thank you.nnRegards,nSeann