Effective laminates are used on the Sizing form just as any other continuously sized material (for example, an aluminum sheet). The materials are added to the Material frame of the Sizing form and the selection is changed to Continuous (red box below). The example shown below for a solid laminate has a range of hybrid effective laminates that were automatically generated from the Composite form. The group variable bounds (green box) reflect a continuous sizing of the ELs from 0.0275" to 0.165" with 21 permutations.
After analysis, the optimized laminate is 0.06875 inches thick and the chosen EL (identified in the blue box) is,
"FP02 (T: 20% 0, 0% 45, 20% 90; F: 0% 0, 60% 45, 0% 90)"
This EL is composed of 20 percent 0° tape, 20 percent 90° tape, and 60 percent 45° fabric.
For strength analysis, the effective laminate is treated as a pseudo three stack laminate. The middle stack is a smeared orthotropic ply that makes up the majority of the laminate thickness. This ply is used to provide the membrane stiffness. See Elastic Properties to understand how the elastic properties of this ply are calculated.
At the IML and OML of the laminate, there are stress evaluation points. These stress evaluation points are the locations at which the software evaluates the strength margins by resolving the laminate strains into ply strains using very thin plies in each orientation.
Important: The allowables stored for the effective laminate, on the material form, are based on the embedded failure theory (Tsai-Hahn). These allowables are not used to write margins of safety for strength. The ply stress/strain allowables for the source orthotropic ply material are used to evaluate strength margins for the laminate.
