Program LAMFAIL

This program performs a first-ply failure analysis of a multi-angle composite laminate, in accordance with the discussion presented in Section 7 of Chapter 7. The program can either predict first-ply failure for a specified combination of unit stress and moment resultants (as discussed in Section 7.3.1), or generate data points that can be used to create a first-ply failure envelope (as discussed in Section 7.4).

The program should be downloaded and saved to a convenient folder location on your computer. Once the program is initiated it will ask whether you wish to read several input values “FROM A FILE? (Y/N)” If you enter a “Y” (or “y”, meaning “yes”) the program will search for a file containing the needed information. If the file is not found you will be directed to enter the values from the keyboard.

If the program has been used to predict first-ply failure for a specified combination of unit stress and moment resultants, then the ply predicted to fail first and the loads at which this failure will occur are printed to the screen. A more detailed description of the analysis is stored in a file named “Answer.txt”.

If the program has been used to generate data points that can be used to create a first-ply failure envelope, then the data points are stored in a file called “Envelop.txt”. A failure envelope can then be created by plotting the data stored in Envelop.txt. This can be accomplished using a third-party software package such as Excel™.

All files created during execution of the program are stored in the folder that contains program LAMFAIL.

Warning: The user must input all values using a consistent system of units. For example, using the SI system of units a typical value of Young’s modulus might be 200 GPa = 200 x 10⁹ N/m², a typical ply thickness might be 0.125 mm, and a thermal expansion coefficient might be -1.0 x 10^-6 m/m-°C. These values should be input as 200.0E9, 0.000125, and -1.0E-6, respectively.