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Author Topic: Non FEA projects (Stiffened panel Design Initial Sizing)  (Read 2888 times)


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Non FEA projects (Stiffened panel Design Initial Sizing)
« on: May 05, 2014, 02:03:44 PM »
Initial Optimization - Non FEA (Request)

When optimizing a stiffened panel or validating Hypersizer to compare buckling results with customer in house software it would be useful to have an alternate input / out method (non FEA)

When validating the Hypersizer results and comparing with hand analysis the stress engineer has two pieces of information.

Skin panel load (Nx) lb/in
Stiffener Load (lb)

Is it feasible for Hypersizer to provide a second load input option? Existing software option: Input Nx , Ny, Nxy on PANEL (stiffener and skin). For a stiffened panel (Nx is applicable for both stringer and stiffener where the Nx INPUT (freebody tab in Sizing) is currently ONLY a function of the skin panel width.

Request 1 - Skin Panel Buckling is often the panel design driver. A stress engineer often knows the skin panel Nx design criteria. Could we have an option to enter load Nx for the skin panel ONLY and let Hypersizer determine the load in the stiffener dependent on the stiffener section options (skin and stringer has similar compressive strain). This appears more logical. Currently I sizing by skin panel Nx. I have to itterate Nx panel until I attain the desired result with the current input options.

Request 2 - The STRESS tab shows internal load results in lb/in for each of the items in the stiffened panel (skin and stringer). Most stress engineers would like the results to be shown as:

Skin lb / in

Stiffener lb (total stiffener axial load) - We could show the load in each element if necessary, i.e. stiffener cap and web.

I suspect this feature would make the non-FEA feature in Hypersizer more useful and consistent with how stress engineers work these problems.


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Re: Non FEA projects (Stiffened panel Design Initial Sizing)
« Reply #1 on: May 06, 2014, 05:25:54 PM »
For a Non-FEA project the total Nx you apply should be..
Skin Nx + (Stiffener Load)/(Stiffener Spacing)

If you're trying to verify/validate the HyperSizer methods, you should consider using the Test Correlation capability. This allows you to store the test failure loads for as many test or verification samples you have, then HyperSizer will create histograms to show the how the analytical prediction stacks up against the other method or the test.

The stiffener crippling force is exported to the word-formatted stress report. In the next V7 software, that stiffener force is also printed to the Margin analysis detail report (Excel-formatted report).

I do like your suggestion of having a place for the stiffener force on the sizing form, possibly the FBD tab. The only problem with showing data on the form is it can only be reported for the controlling load condition.