Issue 47

D. Benasciutti et alii, Frattura ed Integrità Strutturale, 47 (2019) 348-366; DOI: 10.3221/IGF-ESIS.47.26 366 C , C’ covariance matrix of x ( t ) and s ( t ) C ' p covariance matrix in the principal coordinate system d TB ( Ω p,i ( t )) damage of stress projection Ω p,i ( t ) by TB method d ( Ω ) total damage for stress vector Ω ( t ) E [–] expected value G ( f ) one-sided PSD matrix of x ( t ) k σ , k τ inverse slope of tension and torsion S-N curve a J J  a2, amplitude of the square root of second invariant of stress deviator J A,  , J A, τ , k  , k τ amplitude strengths and inverse slopes of the tension and torsion S-N curves in MWD J A,ref , k ref amplitude strength and inverse slope of the reference S-N curve in MWD N A reference number of cycles r ij correlation coefficient between x i ( t ) and x j ( t ) R (  ) correlation matrix of x ( t ) R' (  ) correlation matrix of s ( t ) s ( t ) deviatoric stress vector S H ( f ) two-sided PSD of hydrostatic stress σ H ( t ) S ( f ) two-sided PSD matrix of x ( t ) S' ( f ) two-sided PSD matrix of s ( t ) S ' p ( f ) two-sided PSD matrix in the principal coordinate system T f time to failure (seconds) U matrix of eigenvectors (rotation matrix) Var ( x i ( t )) variance of stress x i ( t ) V H variance of hydrostatic stress σ H ( t ) x ( t ) stress vector in physical space  time lag η TB,i bandwidth correction factor for the PSD of stress projection Ω p,i ( t ) ρ ref stress ratio σ A , τ A strength amplitudes at N A cycles σ H ( t ) hydrostatic stress σ x ( t ), σ y ( t ), τ xy ( t ) stress components σ ( t ) stress tensor σ' ( t ) deviatoric stress tensor Ω p,1 ( t ), Ω p,2 ( t ) , Ω p,3 ( t ) stress projections Ω ( t ) vector of stress projections MWD Modified Wöhler Diagram