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### Author Topic: Regarding "Link facesheet top and bottom stack materials"  (Read 1565 times)

#### orchidworld

• Posts: 42
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##### Regarding "Link facesheet top and bottom stack materials"
« on: August 15, 2014, 01:27:50 AM »
In the "Concept"tab.
there is "Link facesheet top and bottom stack materials"toggle

When the Top and bottom Surface are liminates,
for example: a  sandwich panel or I stiffened with top and bottom faces:
the top surface material:  [0/45/-45/90]
the core is : foam
generally speaking,the bottom surface material should be :[90/-45/45/0]   (symmetry about Core section), but if "Link facesheet top and bottom stack materials" is troggled on, the bottom surface material will also be [0/45/-45/90], the total laminate is [0/45/-45/90/foam/0/45/-45/90],not [0/45/-45/90/foam/90/-45/45/0]

in this case, the top and bottom material need to be defined respectively. Just only the top surface laminate is symmetry, the quick constraint "Link facesheet top and bottom stack materials" is ok, otherwise, it cant be applied.

Question:

if the "Link facesheet top and bottom stack materials" is troggled on, the top and bottom surface have same laminate.  but if the result from 6 Step design (Composites form) is not symmetry, the analysis result will be some error. and because Stiffness {B} will be not equal to zero in fact.

if the "Link facesheet top and bottom stack materials" is troggled off, the top and bottom surface need to be designed respectively, but hypersizer can't design laminate sametime through the 6 step method. it will be not a optimazation result.
« Last Edit: August 15, 2014, 01:35:19 AM by orchidworld »

#### James

• Posts: 230
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##### Re: Regarding "Link facesheet top and bottom stack materials"
« Reply #1 on: August 15, 2014, 12:13:52 PM »
I think what you want to enforce is symmetric cross sections, not symmetric laminates, is this correct? If so, there is a backdoor flag which will enforce HyperSizer generates results with symmetric cross sections.

The flag is in the Geometry checks section. It is called: Generate Only Symmetric Cross Sections. Set this flag = True and turn off the "link skin top and bottom stack materials". This way, HyperSizer size the panels so the Bij terms = 0.

-James

#### orchidworld

• Posts: 42
•
##### Re: Regarding "Link facesheet top and bottom stack materials"
« Reply #2 on: August 17, 2014, 08:35:18 PM »
Thanks James,

but there is not " Generate Only Symmetric Cross Sections."flap. in the backdoor and Geometry checks section.