TUTORIAL VIDEO: https://www.youtube.com/watch?v=0iPqJRC7QzI

The eventual purpose of this tool is to be a general code for all things related to classical laminated plate theory. 

The tool is in initial stages of development but already features a wide array of capabilities. Please keep in mind that this tool still needs to be stress tested and vetted with examples.

Currently, the tool can be used for

• Determining the laminate ABD Matrix with varying levels of failure in each ply. (Q and Qbar matrix output to be implemented)
• Determining the next ply that will fail and which mode of failure will occur.
  • This capability is used iteratively to perform Progressive Failure Analysis.
  • Additionally, stress and strain plots are generated at the failure condition.
• Determining failure envelopes.

The tool features an 8 material built in material database in both Metric and English units (16 materials total). Additionally, 4 additional materials can be input by the user if using the GUI material input method. An unlimited number of materials can be used if using the text box input method.

The tool features a GUI interface for building a layup sequence. Using the GUI, an asymmetric layup can have up to 20 plies, and a symmetric layup can have up to 41 plies.

The failure theories currently available are

• Maximum Stress
• Maximum Strain
• Tsai Wu (4 F12 calculation methods or user input)
• Hill Tsai

Failure conditions can be checked at either the midplane of a ply only or at the ply fringes.

The current stiffness reduction methods available are

• No Reduction (can be used for progressive analysis only with Max Stress and Max Strain
• Full Reduction/Ply Removal (ply stiffness is set to 0, but still acts as a spacer)
• 2 Mode 
  • If there is Fiber Failure the local coordinate stiffness matrix becomes Q = [0, 0, 0; 0, E2, 0; 0, 0, G12] (the stiffness associated with the fiber direction and couplings vanish)
  • If there is any Matrix Failure the local coordinate stiffness matrix becomes Q = [E1, 0, 0; 0, 0, 0; 0, 0, 0] (the stiffness associated with the matrix and couplings vanish)
• 3 Mode
  • Similarly to 2 Mode, Fiber failure decreases E1 related values to 0.
  • Transverse matrix failure decreases E2 relataed values to 0.
  • Shear matrix failure decreases E2 and G12 related values to 0.

Currently only variable mechanical loading can be applied. Future loading to be implemented include

• Fixed mechanical loading.
• Variable and fixed thermal loading.
• Variable and fixed hygral loading.

Sources:

• EM 4133/6133 Mechanics of Composite Materials, Spring 2013, Mississippi State University Course Notes by Dr. Thomas E. Lacy Jr. and Dr. Bert L Smith (of  Wichita State University)
• AAE 555 Mechanics of Composite Materials, Spring 2014, Purdue University Course Notes by Dr. C.T. Sun
• Analysis and Performance of Fiber Composites by Agarwal, Broutman, and Chandrashekhara. Third Edition. (2006, Wiley)

Researchers should cite this work as follows:

• Anthony Favaloro (2017), "Laminate Failure Analysis (Progressive and Envelopes)," https://cdmhub.org/resources/progfail.

  BibTex | EndNote

1. Failure
2. Laminate