Lamina Correction Factors

Since lamina correction factors are defined as a function of reference temperature, laminate thickness, hole diameter, and ply orientation; the laminate geometry and reference temperature are defined at the top of the Correction Factors form.

The values entered for these options will change the correction factors that are displayed in the form. This allows you to perform quick "what if" studies to view the corrected lamina properties for unique laminate geometries and reference temperatures.

Note that Hole Diameter (in) is disabled in the example. This is because there are no correction factors defined as a function of hole diameter for this material. Also notice that to enter the ply orientation, you may only enter values for %0s and %45s. The %90s and AML are dependent values and are not direct user input.

The legend at the top is provided to help you quickly see which lamina properties have been corrected with a constant correction factor (blue) or a polynomial equation of laminate geometry (pink).

You may define constant correction factors directly in the form or you may double-click the desired field to enter non-constant correction factors. See Define/Modify Lamina Correction Factors.

To see the corrected properties, click Plot in the Laminate Definition frame. See Plotting Corrected Properties.

Hide Unused Corrections

When the Hide unused corrections check box is selected, a condensed version of the form is displayed where the columns of the unused correction factors are removed from the form. For this example, the form will be displayed with only the Ply Laminate and BVID correction factor columns.

• Uncorrected Value The uncorrected values are displayed in yellow. These property values are consistent with the temperature-dependent lamina properties entered directly into the Orthotropic Material form. These are considered "pristine" or uncorrected values. All composite material strength methods, except BJSFM, use corrected properties when calculating the margins of safety.
• Ply Laminate This is used to adjust the lamina properties to account for the variation in ply properties due to interaction in the laminate.
• BVID (Barely visible impact damage) This is used to reduce the pristine lamina properties for laminates that may develop internal damage which cannot be detected by visual inspection. Visible damage is usually defined as a physical defect/dent greater than 0.05 inch in depth.
• Co-Cure Co-curing is the act of curing a laminate to a pre-cured laminate or core during the same cure cycle. This reduces the ply properties based on the assumption that co-curing manufacturing techniques reduce the contact pressure required to remove voids. The voids in the matrix reduce the load transferring capability between the fiber and the matrix, ultimately decreasing the stiffness and strength of the ply material.
• Thickness This provides the option to adjust the lamina properties to account for variable laminate thickness.
• AFP Automated fiber placement (AFP) allows reduction of the material properties to account for the presence of defects such as gaps, overlaps, and twisted tows appearing in the final part.
• NPT Noise perforated transmissibility (NPT) reduces the stiffness and strength assuming the skin has been perforated to reduce vibration and noise.
• Ageing This reduces the material properties to account for the degradation of material properties from exposure to environmental aspects such as temperature and moisture.
• Corrected Value The corrected value is displayed in green. HyperSizer uses the corrected property values for all composite strength and stability analysis, except BJSFM which has its own correction factors on the Bolted Joint Analysis form. The corrected stress/strain allowables are considered the damage tolerant design allowables.