mean(mean(shell.llem1.lsf1.f_i)) 1 "Tsai-Wu orthotropic failure index"
mean(mean(shell.llem1.lsf2.f_i)) 1 "Hoffman failure index"
mean(mean(shell.llem1.lsf3.f_i)) 1 "Tsai-Hill failure index, plane stress"
mean(mean(shell.llem1.lsf4.f_i)) 1 "Azzi-Tsai-Hill failure index"
mean(mean(shell.llem1.lsf5.f_i)) 1 "Norris failure index"
mean(mean(shell.llem1.lsf6.f_i)) 1 "Tsai-Wu anisotropic failure index"
mean(mean(shell.llem1.f_i_com)) 1 "Combined failure index"