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mansin

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Posts posted by mansin


  1. Hi ,

    I wanted to mesh a lot of lines with variable lengths in model by using tcl script, but I found the sample script in help is not intelligent, for example

     

    *createmark lines 1 15 18

    *linemesh_preparedata lines 1 30

    *linemesh_saveparameters 0 3 0 0

    *linemesh_saveparameters 1 2 0 0

    *linemesh_savedata1 1 5 0 0

     

    The parameter "density" in line 3 and 4 are manually assigned, and the "segment" and "density" parameteres must be strictly matched. If the length of each line are different, the density are also different. So, a lot of *linemesh_saveparameters commands are needed. It is not acceptable for this meshing scripting.

    So, is there a way to mesh lines with constant element size?


  2. In force case, I found that, even though using calculated dependent node with RBE3 element, the concentrated force cannot be distributed equally to all nodes of the truncated model. However, when I use the distributed nodal force directly and planar symmetry constraints, the results are equivalent to those of the whole model.

    In torque case, I tried to use PERBC bulk data to simulate the cyclic symmetry, but I don't get any satisfied results. Doesn't the RBE3 element located in symmetry plane or center suitable for  symmetry constraint s?

    F_Tq_on_tube_Quarter-PERBC.fem


  3. Hi,

    I have a problem with planar symmetry on a tube. One end of this tube is full constrained, the distributed force on the other end is applied by the concentrate force (or torque) on dependent node of RBE3 element. To reduce the model, a quarter of this tube is constructed. For the nodes on symmetry plane (X-plane and Y-plane) except the dependent node of RBE3 element, the (156 and 246)DOFs of these nodes are constrained. The model is shown as follow: (Fz=1000, Tz=2000)

     image.png.937e1b55a51655ba6beca8a46d02087f.pngimage.png.a26c308b3f79a1b925972bcefaadb3a7.pngimage.png.33eb4293c52b5cb10303485d739308ae.png

    However, the results of the two loads are not reasonable and right.

    image.png.2be12d4820ee5d202f5defa919fb69d4.pngimage.png.48fc7ff4c449f17cdcfa7173f7d37437.png

    I think the reason is the symmetry constraint of RBE3 element is not setup correctly. How to fix it?

    I attach the results of the whole model (Radius=20, length=200, Thickness=2, Fz=4000, Tz=8000):

    image.png.d4ad1de09ac229b4e78dd24bb89212e4.pngimage.png.c8b844599d0e47de697cf54a31247a43.png


  4. Hi, tinh

    The purpose of this test is to get an shape variable which is able to be used in optimization. Your advised method is based on the pre-establised arc. The constraints of the symmetry and tangency are ensured by creating the new arc manually. I'm looking for a simple and direct method to establish the relationship between the designable shape variable and the radius of this arc.

    Many thanks.


  5. Hi, Mrt

    I tried this test by morph tools many times. I found that, in "alter dimensions" subpanel, we can only use the "fillet" approach to keep the tangency of arc AB at point A, but the symmetry of this arc has no way to be constrained by assign tangent vector.

    If do this test in whole model, I guess this problem could be solved easily, because the constraint of the symmetry of the arc does not existed anymore. But if the geometry model is huge and complex, the symmetry constraint in half model like this problem is still nesscessary.

    Your idea, do it like HM-3530 by map to geometry, is still worth to try. I will try it.

    Many thanks.


  6. Hi,

    1. Is the material orientation of each ply the same? I assigned different material orientations to each ply, but I cannot get the expected material orientations.

    2. How to assign material orientation to elements with ply (fiber) direction? I try to assign the material orientation to plies with the cooridinate systems each ply used in drapping operations. But I found the obtained material orientation is not coincident with the ply direction. The attached pictures  are the results of this test (for example, the directions in face A). I want to get the same directions, but I don't know how to do.

     

    image.png.b68aff213f702b6aa15ab1479e28c5f8.pngimage.png.51620262eea18963bad1b2f22c26c181.png

    Material_Direction_of_Ply.hm

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