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Material Strength Composites: Laminate Approach / Re: Carpet plots to polynomial
« Last post by August on May 20, 2019, 12:50:43 PM »
Here is one suggestion (assuming the raw data used to generate the plot is unavailable):

First, extract data from the carpet plots. I like to use WebPlotDigitizer (https://automeris.io/WebPlotDigitizer/). Extract at least 10 or so data points along each %45 curve. Each data point will have three associated values: allowable, %0, %45.

Next, use the extracted data in Excel to perform multivariate regression to get the terms A-H for the polynomial equation. The allowable will be the dependent variable and the terms of our polynomial will be the independent variables (%0, %0^2, %45, %45^2, etc).

Here's a helpful link for multivariate regression in Excel:

http://cameron.econ.ucdavis.edu/excel/ex61multipleregression.html

-August
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In order for HyperSizer to derive effective laminate interlaminar strength properties is to assign a strength correction factor/equation based on ply percentages, laminate thickness, etc. to the parent material. The reason being is that there is not a HyperSizer built in methodology for deriving interlaminar strength properties for effective laminates.   

Link to help for correction equations: http://hypersizer.com/help_7.3/#Materials/Correct/correction-lamina.php%3FTocPath%3DFeatures%7CMaterials%7COrthotropic%2520Correction%2520Factors%7C_____3

Be sure to regenerate the effective laminates after updating the parent material.

-Brent
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Material Strength Composites: Laminate Approach / Carpet plots to polynomial
« Last post by RobDexter on May 20, 2019, 09:18:58 AM »
Hi, Does anyone have any advice on how to fit the polynomial expression for laminate properties to data from carpet plots please?

I've seen recommendations to enter laminate allowables as polynomials. I have carpet plots for several laminate properties, but can't get a reasonable match using the polynomial form.  I've been running Excel solver with various constraints, but didn't get anything close.

Alternatively, if I can't get a good match, is there a way to define individual curves for a number of different %0 laminates, rather in the one equation?
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Following creation of effective laminates from an orthotropic material, which has the out-of-plane interlaminar properties Fsu13 & Fsu23 populated, the Fsu13 & Fsu23 are not populated. Why is this?

Is it because the calculation of elastic stiffness properties and strength allowables for the effective laminate can not derive interlaminar shear allowables?

Could the EL not be populated with the parent orthotropic material values? Is it because it is an orthotropic "black metal" with no ply interfaces? and no ply based calculations possible in subsequent analyses using EL?
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Miscellaneous Software Topics / Re: Recursive Load Error
« Last post by Stephen on May 01, 2019, 09:16:11 AM »
Mark,

I'm reaching out via email to gather more information.

Thanks,
Stephen
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Miscellaneous Software Topics / Re: Recursive Load Error
« Last post by mnoftz on May 01, 2019, 08:21:51 AM »
Hi Stephen,

We are using HypersizerPro v7.3.57 with Nastran 2018.2 and Patran 2018 installed.

This error is specific to the Assembly Projects tab. It occurs for beam elements during "importing material data" and "importing pressure/temperature loads." It only occurs in one load case. The affected beam assemblies will immediately throw this error upon sizing initiation. Skin assemblies are not affected.

After some tweaking, we found that the error does not occur if we split the force and pressure loading into different subcases. We also found that the error does not occur if we size components normally in the sizing tab or in HyperFEA.

-Mark
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Miscellaneous Software Topics / Re: Recursive Load Error
« Last post by Stephen on April 29, 2019, 03:45:36 PM »
Hi Mark,

Can you provide a little more information about the problem? For instance, what version of HyperSizer are you using? And what is the solver you are using? Nastran?

Thanks,
Stephen
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Miscellaneous Software Topics / Recursive Load Error
« Last post by mnoftz on April 29, 2019, 03:24:52 PM »
Hello,

We came across this message when sizing one of our models last week. Despite our attempts to rename and re-apply the loads within Patran, there seems to be a recursive call to a non-existent load entry that appears only in a singular load cases. We have had a hard time replicating this error or trouble-shooting what causes it (load cases that share the same pressure conditions run perfect).

Besides completely throwing out this load-case, has anyone ever encountered this error and found a solution?

Best,

Mark
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Miscellaneous Software Topics / Re: Isometric View within FEM Viewer
« Last post by martinjb on April 29, 2019, 08:26:11 AM »
Thanks
10
HyperSizer manages the CBAR element reference planes for discretely-meshed stringer segments.

You can force the software to remove reference planes, effectively setting the stringer segment reference to the neutral axis. It's a backdoor data setting.

Backdoor data form: http://hypersizer.com/help_7.3/#BackdoorData/bd-00-about.php%3FTocPath%3DSoftware%2520Forms%7CBackdoor%2520Data%2520Form%7C_____1

FEM Import/Update > "Export offset for full stiffener discrete beam elements" = No.

I hope this is helpful.

-James
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