Interpreting the format of Material Library .esp files

[zapem]

I am looking for information regarding the format material.esp files. I am creating a new library and want to be able to write it in a notepad and then read it into Nastran for Windows. I have looked at the .esp file and have been able to decipher the majority of the values (particularly for isotropic and linear materials). The first three lines are Young's modulus, shear modulus and poisson's ratio. After that the next seven lines are not clear to me. If someone knows what they are please contact me.
Thanks!
Mike

 

[tstanley]

Wouldn't it be possible just to create a dummy material in Nastran and label each box 1,2,3 etc., save it to the library, then you could see the corresponding column in the .esp file.

Personally I would be happy with a translator to translate my custom libraries (.esp files) from one software version to the next.

Tom Stanley

 

[zapem]

Thanks for the reply. I did go through and make some dummy materials changing only one value (to 1) and leaving all the others at zero. What I found was that the five lines of code after elasticity, shear and poisson's were the upper diagonal of a symmetrical stiffness matrix for a 3D case that Nastran automatically calculates and saves to the file. The next two lines are the upper diagonal of a symmetrical stiffness matrix for a 2D case. Seeing the pattern in which the shear modulus repeated at the end of the code is what tipped me off. Thanks again for the reply and I am sure I will have more questions in the future.