Maximizing Strength-to-Weight (Sandwich Panels)


Many parts carry load in bending.  In this application, you want to use the automatic sandwich panel functionality in Eiger. Ensure that fiber sections are at the top and bottom of the part.

 

An Sandwich Panel is the composites version of an I-Beam.

         

  • The carbon fiber forms the top and bottom of the panel (the bread), and a lightweight honeycomb core forms the interior.  
    • The majority of the load (stress) is resisted by the carbon.  The honeycomb structure transfers the sheer stress between the top and bottom layers.  
  • The Flange on the I-Beam carries the load, while the web transfers the sheer stress. 

 

 

 

Automatic Sandwich Panels in Eiger

 

 

  • Notice the Kevlar fibers in the top and bottom of the quad copter.  This creates a sandwich panel to maximize the strength to weight of the part.
  • If you want the part to be stronger, a good rule of thumb is to add to the top and bottom most layers of the part.

 

 

Example of Poor fiber layout (fiber in middle)

 

 

  • If the goal is to make a flexible part, loading fiber in the middle is a fine way to do it.
  • This part layout concentrates the fiber in the middle, and will be exponentially weaker than the above sandwich panel (for the same amount of fiber used).