Hello,
Purpose of *CONTROL_REFERENCE_CONFIGURATION is to find an approximate reference geometry (stress free) given a measured/known deformed geometry. A solution to this inverse problem is found iteratively by means of an optimization method. This keyword needs to be in the main keyword file, not in any of the include files. case must be used on the command line (see Remark 2).
Target file contain the nodes subjected to optimization and has the same simple structure:
Please read the keyword description in Keyword Manual I: https://lsdyna.ansys.com/manuals/
References for *CONTROL_REFERENCE_CONFIGURATION might be also helpful:
1] Sellier, M, “An iterative method for the inverse elasto-static problem,” Journal of Fluids and Structures, Volume 27, issue 8, (2011)
[2] Rausch, M.K., Genet M., and Humphrey J.D, “An augmented iterative method for identifying a stress-free reference configuration in image-based biomechanical modeling” Journal of Biomechanics 58 (2017) 227-231.
Please let me know if that helps,
Thank you,
Alex