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.