type: phenopowerlaw

references:
  - T.J. Barrett and M. Knezevic,
    Computer Methods in Applied Mechanics and Engineering 354:245-270, 2019,
    https://doi.org/10.1016/j.cma.2019.05.035,
    fitted to data shown in Fig 1 and Fig. 2a

output: [xi_sl, gamma_sl]

N_sl: [12]

dot_gamma_0_sl: [0.001]
n_sl: [20]
a_sl: [3.7]
xi_0_sl: [76.e+6]
xi_inf_sl: [266.e+6]
h_0_sl-sl: [1.02e+9]
h_sl-sl: [1, 1, 5.123, 0.574, 1.123, 1.123, 1]