图9. 横-斜裂纹转子振动谱特征参数对方向角的敏感性: $\theta_{1} =10^{{\circ}}\sim 90^{{\circ}}$, $\theta_{2} = 90^{{\circ}}$
Fig. 9. Sensitivity of spectral parameters of the transverse slant crack to orientation angle: $\theta_{1} = 10^{{\circ}}\sim 90^{{\circ}}$, $\theta_{2} =90^{{\circ}}$