Reporting an error in Anisotropic Elasticity Matrix calculation

- February 17, 2023 at 1:48 pm
  
  Katja Mustonen
  Subscriber
  
  Hi!
  
  I want to notify you that your software calculates the D66 cell in Anisotropic Elasticity stiffness and compliance matrices incorrectly. When using Matrix Type Stiffness, Format IEEE, and Point Group 6mm, your software says that D66 = 2*(D11-D12), when in actuality it should be (D11-D12)/2. Similarly, when using Matrix Type Compliance, Format IEEE, and Point Group 6mm, your software says that D66 = (D11-D12)/2, when in actuality it should be 2*(D11-D12) (see https://ntrs.nasa.gov/api/citations/20030014725/downloads/20030014725.pdf).
  
  Note that the unit of the stiffness matrix C is Pa and the unit of the compliance matrix S is Pa^(-1). Thus, one cannot simply switch the matrices' names.
  I already contacted Ansys support about this error.
  
  Regards,
  Katja
- February 20, 2023 at 3:21 pm
  
  dlooman
  Ansys Employee
  
  I don't see a service request in the tech. support tracking system under your name. Could you give the specific location in the help where you believe D66 is defined incorrectly? (Or the service request number if under a different name.)
- February 22, 2023 at 1:11 pm
  
  Katja Mustonen
  Subscriber
  
  Hi Dave!
  Can you see the images in my post? There you can see, that D66 has been calculated incorrectly. I don't think it is defined in the help anywhere. There is no service request number, because I was guided to post about this here.
- February 22, 2023 at 5:58 pm
  
  dlooman
  Ansys Employee
  
  No, I can't. Can you attach them as pdf files?