## 5 Conclusions
**Nomenclature**  
**Notation**: **Description**:  
\(\sigma_{jk}\): Second-order tensor in the global coordinate system:  
\(\sigma_{ryk}\): Second-order tensor in the local coordinate system:  
\(\alpha_{j\gamma}\), \(\alpha_{yk}\): Cosine of the included angle of the corresponding axes of two coordinate systems:  
\(\sigma_{1}\),\(\sigma_{2}\),\(\sigma_{3}\): Principal stress:  
\(a_{\perp}\): Utilization degree under normal stress in the x-direction of local coordinates:  
\(a_{\parallel}\): Utilization degree under normal stress in the y-direction of local coordinates:  
\(a_{\tau}\): Utilization degree under shear stress:  
\([\sigma_{\perp}]\), \([\sigma_{\parallel}]\), \([\tau]\): Allowable fatigue strength values:  
\(f_{v}\): Phase effect of \(\sigma_{\perp}\) and \(\sigma_{\parallel}\) ranging from \(-1.0\) to \(+1.0\):  
\(\alpha_{v}\): Comprehensive degree of utilization:  
\(M_{\sigma}\): Moderate stress sensitivity coefficients of normal stress:  
\(M_{\tau}\): Moderate stress sensitivity coefficients of shear stress:  
\(N_{i}\): Accumulative cycle number of the measured stress range within the stress range:  
\(\Delta\sigma_{i}\): Stress range of the principal stress:  
\(\Delta\sigma_{c}\): Corresponding fatigue strength at specified cycles; the value depends on different structural classifications:  
\(\Delta\sigma\): Allowable stress range:  
\(m_{1},m_{2}\): Curve slope of the S-\(N\) curve:  
\(\gamma_{Ff}\): Partial coefficient of the uncertainty considering the load spectrum and response:  
\(\gamma_{mf}\): analysis, generally equal to 1:  
\(\sigma_{m}\): Mean value of normal stress:  
\(\sigma_{a}\): Normal stress amplitude:  
\(\sigma_{min}\): Minimum normal stress:  
\(\sigma_{max}\): Maximum normal stress:  
\(\sigma_{p}\): Maximum principal stress:  
\(R\): Stress ratio of minimum stress-to-maximum stress:  
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