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If you want to capture the strains due to temperature change post-cure, HyperSizer can handle them in the same way it handles other thermal loading. So in that sense, there is not a fundamental difference between the two.

What you would likely want to do is define an initial temperature in your FEM (this is the cure temperature), as well as the applied temperature (this is the operating temperature). When you use this FEM in HyperSizer, it will automatically apply thermal loads according to the deltaT from initial to applied. Since HyperSizer handles this the same way as other thermal loading, you can calculate strains without applying other loads.

As far as the theory, you did in fact point to the correct HME (here). Similar processes are used for both stiffened panels and laminates. Specifically see Section 4.1 which explains the steps HyperSizer takes to determine the ply-level strains resulting from applied thermal loads.

As a note, if you are using non-FEA projects instead, the same process applies, but you will specify the relevant information (initial and applied temperatures) in HyperSizer rather than in FEA.

Let me know if I can answer other questions or clear anything up.

Thermoelastic Stiffness Formulation / Residual stress and strain for composite laminates
« Last post by garyjh on November 28, 2017, 04:44:00 AM »
How are residual stress and, in particular, strain for composite laminates determined following cure?

How are they differentiated from mechanical and thermal loading?

Can see CTE's input in the orthotropic material creation & also, what looks like deltaT inputs from reference T and thermal expansion & bending effects in the Laminate Analysis and Effective Laminate Properties. But not clear how the residual strains are calculated, or how added or subtracted from mechanical strains, then MS calculated?

Can the strains be calculated without any mechanical or thermal loading i.e. deltaT is cure temp cool down to room temp? Then deltaT is room temp to operating temp?

Please can you help explain or point me to the relevant help & theory  documentation.

Documentation I can find is:
"HyperSizer_Stiffness_Method_-_Thermoelastic_In-Plane_Stiffness_Formulation.HME.pdf". But this looks like for a stiffened panel. Is there some other basic laminate HME that explains it?

And from help when in Laminate Analysis and Effective Laminate Properties:
"Ref Temperature This is the temperature at which the ply material properties are taken. The default temperature is 72° F.
To add another temperature to the list, type the temperature in the box and press [Enter].
If an effective laminate is created, material properties will be generated for each temperature in this list.
Outer/Midplane/Inner Fiber Delta T Specifies through-thickness changes in temperature at the inner, midplane, and outer fibers. Changes are taken to the reference temperature (above). Given these three temperature points, the final temperature distribution is linearly interpolated through the thickness.
The final temperature at each ply is the temperature at which material properties are taken. The analysis will not compute thermally induced ply stresses and strains. However, if the analysis is done in the Sizing form, thermally induced ply stresses and strains will be captured."

So it looks like it is calculated in the Sizing form? Is the strain breakdown of residual, mech & thermal included in the stress report?

Brent, is this something that we could include in the smeared grid stiffened plugin package? Then we could provide it to Martin.


Currently there is not a native capability in HyperSizer to satisfy your stiffener/skin geometry constraints. However, these geometry checks are good candidates for an analysis plugin in HyperSizer. An analysis plugin can act as a geometry check in the failure tab returning either a "pass" or "fail" for the candidate design being analyzed.

Our help system contains a detailed tutorial explaining how to get started writing analysis plugins. There is also a good amount of sample code available to download on our help system  including a stiffener EA geometry check plugin.

See help topic:   

Within the Orthogrid concept is there a method where i can allow Hypersizer to complete the sizing of the components but respecting some minimum machining constraints placed upon it. 
As a guideline, if the following web thickness v maximum spacing had been stipulated - 

dimensions in mm
 Web       Max
Thick    Spacing
1.0        50
1.5        90
2.6        150
3.5        350

Minimum spacing in all concepts = 50mm

Is there an option within Hyeprsizer that it checks all the configurations of web thickness v Spacing?  I understand that it may take longer to run the analysis.

I have found way round it by running 4 separate jobs, sizing, create an excel stress report and then extract the lightest solution.  Once the minimum mass solution is known, the project can be reanalysed with the corresponding dimensions. 

This is a viable method but it seems a very manual technique and I was wondering if this is the most efficient way or I have missed some methodology within Hypersizer?

I'm facing a problem during Hyperfea optimization process combined with FEA constraints implementation related to the spars of a wingbox . More in detail, although max displacement target value (Tmax=945 mm) is achieved after 5 iterations (943.19 mm)the following iterations don't seem to converge to above mentioned value instead continue to reduce max displacement value by increasing membrane stiffness and mass of affected components (spars caps). In attachment you can find some pictures which i hope will help you to better understand the problem.

thank you

Miscellaneous Software Topics / Re: 90Grid - Grid stiffened Panel Family
« Last post by James on October 12, 2017, 12:56:34 PM »

The help file is out of date. The 90 grid has been removed from the interface.

To change the stiffener direction, you should rotate the material vectors so they are pointed in the assumed stiffener direction. You can do this in the FEM viewer. See:
Hit the nail on the head.

Thank you - I switched the flag to No and the anlysis took 00:01:10.  Back to a similar time frame to the previous model.

Thanks again
Miscellaneous Software Topics / 90Grid - Grid stiffened Panel Family
« Last post by martinjb on October 12, 2017, 07:56:17 AM »
Dear Hypersizer,

I have just been looking at different concepts for the Grid Stiffened Panel Family and I was looking to try and understand if the stiffeners would be better aligned in the 0 or 90 deg direction.  In the concept selection tab it only allows me to choose a 0Grid.  Has the 90 Grid been removed from the family?

Looking at the help file Software Forms/Sizing Form/Dimensions Tab/Panel and Beam Families/Grid Stiffened Panel Family it shows the options that can be selected on the 90Grid.

Is the helpfile out of date or has my installtion not completed fully?

Also the S0 has no ticks in the table.  Is this an omission or does the S0 column need to be in the helpfile?

Miscellaneous Software Topics / Re: Analysis time increased with 7.3.37 installation
« Last post by James on October 12, 2017, 07:09:10 AM »
Hi Martin, I believe this has to do with the exhaustive search flag in the backdoor data options.

Open the backdoor data form > Buckling Coefficients tab > Panel buckling energy solution exhaustive search

Set flag = No.

This flag prompts HyperSizer to try more m and n half modes for the energy buckling solution. This will slow the software significantly. It is only necessary for the buckling analysis of curved panels with long aspect ratios (> 15/1).

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