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Author Topic: Laminate Allowables Tab  (Read 5039 times)

orchidworld

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Laminate Allowables Tab
« on: September 05, 2012, 05:02:51 AM »
Dear everyone,
there is "Laminate Allowables Tab" in the orthotropic form.
Regarding the help topic:
Since it is impossible to test all laminate configurations, the laminate allowables are stored as a function of fiber percentages to characterize many laminate configurations with a single strain curve. As with all material properties, HyperSizer will interpolate but never extrapolate to find appropriate laminate strain allowable properties.
For Example:  Select "Percent 45 degree fiber" in the property method     
                         0     4400
                         20    4900
                         40    5300
                         60    5700
                         80    6100

Hypersizer can obtain 50%   77%...    allowable stain values.

i want to know, these data is 45 degree fiber function, if 0 degree and other degree fiber in the laminates are different, these data should be also different??
So i dont very clear about "laminate allowable tab"'s function in practice.

Thanks for explanation..

James

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Re: Laminate Allowables Tab
« Reply #1 on: September 05, 2012, 12:15:52 PM »
Laminate-based failure theories quantify failure of an overall laminate rather than failure of an individual ply. For laminate strength analysis, the overall laminate strains are compared with laminate strain allowables.

The laminate allowables are defined in the orthotropic material form as a function of ply percentages. Ply percentages can be expressed as: percent 0° fibers (%0), percent ±45° fibers (%45), Angle Minus Load (AML = %45 - %0), or as a general polynomial. In addition, laminate allowables can also have correction factors for thickness, percent 0, 45 and 90 degree fibers, reference temperature, etc.

For more information, please see the following help topic:
http://hypersizer.com/help/index.php#ManageMaterials/mgm-ply_vs_laminate.php

-James

orchidworld

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Re: Laminate Allowables Tab
« Reply #2 on: September 19, 2012, 04:32:13 AM »
Laminate-based failure theories quantify failure of an overall laminate rather than failure of an individual ply. For laminate strength analysis, the overall laminate strains are compared with laminate strain allowables.

The laminate allowables are defined in the orthotropic material form as a function of ply percentages. Ply percentages can be expressed as: percent 0° fibers (%0), percent ±45° fibers (%45), Angle Minus Load (AML = %45 - %0), or as a general polynomial. In addition, laminate allowables can also have correction factors for thickness, percent 0, 45 and 90 degree fibers, reference temperature, etc.

For more information, please see the following help topic:
http://hypersizer.com/help/index.php#ManageMaterials/mgm-ply_vs_laminate.php

-James

Thanks James,

i read the help again, i am sorry i still have some confusions about laminate Allowable.

i dont know how to express more clear about my confusion, i give an example, hope you can understand :

For example:   

Orthotropic Name: A-glassfiber,
 
Material Properties: Stiffness, lamina Stress/Strain Allowables....,it is nearly same with isotropic material test method.
but:
How to determine "Laminate Allowables "?
if i choose 0degree fiber as "property method", i need produce test specimens, there are 2 variables(0degree and 45degree fiber), We should test :40%0degree/40%45degree/20% specimens, or 40%0degree/20%45degree/40%, or other countless combinations with 40%0degree is unchange. The test result is as "Laminate allowables".


Assume?

if the "laminate allowables" is set and it is ok.

now i need to analysis my design with laminate-based failure.

my laminate with different ply percentage(0/45/90=20%/30%/50%, 20%/50%/30%,......)
the 0degree percentage is same, but the strain should be different,
"0degreee-laminate allowable" is same(with 20% 0degree).


i may misunderstand about "Laminate allowables",please give an example to instruction, thanks.

James

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Re: Laminate Allowables Tab
« Reply #3 on: September 23, 2012, 05:54:03 PM »
Perhaps you should consider using the AML (angle minus load) technique for storing laminate strain allowables.

AML = %45 degree fibers - %0 degree fibers

This would account for laminates with varying stiffnesses.

-James