type: Hooke
references:
  - D. Music et al.,
    Applied Physics Letters 99(19):191904, 2007,
    https://doi.org/10.1063/1.2807677
  - S.L. Wong et al.,
    Acta Materialia 118:140-151, 2016,
    https://doi.org/10.1016/j.actamat.2016.07.032
C_11: 175.0e+9
C_12: 115.0e+9
C_44: 135.0e+9