mansin

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Posts posted by mansin


Hi,
I have been confused by the parameter G in GRAV bulk data entry. I think this parameter is the acceleration of gravity. If I use the unit system of “kg, N, mm, MPa”, Should the parameter G be set to 9810 ？ I found that If I set G to 9810, the displacement of the structure in the case of gravity is too large.


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?


Hi,
When I tested the example of OS1393 in HyperWorks 2017, a lot of errors were reported. The settings in this example were followed by the document. I don't know where the problem is.

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?

Hi, tinh
How to reduce the whole model and setup cyclic constraints on the quarter model?


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 (Xplane and Yplane) 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)
However, the results of the two loads are not reasonable and right.
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):

Hi, Toan Nguyen
If I apply the shape with different multiplier, the obtained intermediate curve is not an arc, actually it is an interpolated curve, just like this:
Many thanks.


Hi, Prakash Pagadala
I cannot assign different material orientations to each ply element, although I set the ply angle of the two plies in one coordinate system. Are the material orientations in each ply of composite material's model the same?
Many Thanks.

Can anybody give me some advices?
Thanks.

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 preestablised 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.

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 HM3530 by map to geometry, is still worth to try. I will try it.
Many thanks.

Hi, Mrt
Thank you for your reply and suggestion.
Do you mean that recreating the geometry with new arc CD and then remesh the new shape? But I want to do this by morphing.

Can't this constraint be achieved in HyperMorph?

I want to assign the two plies with 0 degree in two different coordinate systems.

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.

Hi, everyone.
I encountered a problem when morphing an arc. The arc cannot keep the tangency on symmetry plane when altering the radius of the arc (shown in figure). How to keep the vertical tangential direction on point B and D while morphing?
Thanks.

Hi, @tinh
I run this code (drape_test.tcl) in command window:
"C:\Program Files\Altair\2017\hm\bin\win64\hmbatch.exe" tcl "E:\HyperWorks_Work\Drape_test\drape_test.tcl"
Some errors are obtained:
How to solve this problem?
Thanks.


Hi, @tinh.
I found the code you advised cannot be run in HyperStudy. It seems that the code cannot be recogonized by HyperStudy properly. How to solve this new problem?
Thanks.

How to properly set the G parameter in GRAV bulk data entry?
in Altair OptiStruct
Posted · Report reply
Thank you.