DVS 1608
Version: September 2011 Edition
List of Classification Parameters
 Evaluation Distance
 Reference distance to find the evaluation location from the weld element at which the stress values are extracted.
 Weld Width
 Width of the weld material from the web wall. This parameter is ignored
if specifying the evaluation distance is done manually.Note: Refer to  Find Evaluation Positions.
 Grinding Bonus
 Parameter to specify if the grinding bonus has to be considered or not.
 Effective Weld Thickness
 This parameter is used to consider the influence of welds which do not cover the same cross section area as indicated by the shell element in the respective evaluation location. It modifies the stress at the evaluation location based on the ratio to the shell thickness. (a > 0)
 Mean Stress Sensitivity – Normal
 Mean stress sensitivity factor used for the normal direction evaluation.
 Mean Stress Sensitivity – Shear
 Mean stress sensitivity factor used for the shear direction evaluation.
 Notch Class  Transverse Location_X
 Notch class definition considered for the fatigue limit calculation for the normal stress component in the transverse direction (perpendicular to the axis of the weld) at ‘X’.
 Notch Class  Longitudinal Location_X:
 Notch class definition considered for the fatigue limit calculation for the normal stress component in the longitudinal direction (parallel to the axis of the weld) at ‘X’.
 Notch Class  Shear Location_X
 Notch class definition considered for the shear stress component at
‘X’.Note: Where ‘X’ can be any evaluation location.
 Material Yield  Location_X
 Material yield value used for the static evaluation.
Formulation
 Stress Component considered for evaluation

 σ_{T}: Transverse component perpendicular to the axis of the weld
 σ_{L}: Longitudinal component parallel to the axis of the weld
 τ: Shear Component
 Corrected stress calculation
 The stress value correction is carried out using the effective weld
thickness.Note: Refer to  Common Classification Parameters
 Calculation of the Assessment stress value (numerator in utilization formulae)
σ_{TA} (Stress Amplitude) = (σ_{Tmax}  σ_{Tmin}) / 2
The stress amplitude is used as the numerator for the utilization calculation.
 Fatigue Limit Calculation

The fatigue limit values (σ_{Tzul}, σ_{Lzul}, and τ_{zul}), are calculated based on the following regimes of Stress Ratio ®,
Reference: the DVS1608 regulation document section 7.2.2.
For nominal stress (longitudinal σ_{Lzul} and transverse σ_{Tzul})
Regime 1: $\left({R}_{\sigma}>\text{}1\right)$$${\sigma}_{zul}=54\cdot {1.04}^{x}\left(MPa\right)$$Regime 2: $\left(\text{}\infty \text{}\le \text{}{R}_{\sigma}\le \text{}0\right)$$${\sigma}_{zul}=46\cdot {1.04}^{x}\left(\frac{1}{1+{M}_{\sigma}\frac{1+{R}_{\sigma}}{1{R}_{\sigma}}}\right)\left(MPa\right)$$Regime 3: $\left(0\text{}\text{}{R}_{\sigma}\text{}0.5\right)$$${\sigma}_{zul}=42\cdot {1.04}^{x}\left(\frac{1}{1+\frac{{M}_{\sigma}}{3}\left(\frac{1+{R}_{\sigma}}{1{R}_{\sigma}}\right)}\right)\left(MPa\right)$$Regime 4: $\left(0.5\text{}\le \text{}{R}_{\sigma}\text{}1\right)$$${\sigma}_{zul}=36.5\cdot {1.04}^{x}\left(MPa\right)$$${M}_{\tau}$ is the mean stress sensitivity, the exponent x in the above equations is queried from the below notch detail tables:
Curve B B B+ C C C+ D D x 6 7 8 9 10 11 12 13 Curve E1+ E1 E1 E4+ E4 E4 E5+ E5 E5 E6+ E6 E6 X 14 15 16 17 18 19 20 21 22 23 24 25 Curve F1+ F1 F2 x 26 27 28 For shear stress, ${\tau}_{zul}$ ,
Regime 2: $(1\text{}\le \text{}{R}_{\tau}\le \text{}0)$$${\tau}_{zul}=28\cdot {1.04}^{x}\left(\frac{1}{1+{M}_{\tau}\frac{1+{R}_{\tau}}{1{R}_{\tau}}}\right)\left(MPa\right)$$Regime 3: $(0\text{}\text{}{R}_{\tau}\text{}0.5)$$${\tau}_{zul}=26.5\cdot {1.04}^{x}\left(\frac{1}{1+\frac{{M}_{\tau}}{3}\left(\frac{1+{R}_{\tau}}{1{R}_{\tau}}\right)}\right)\left(MPa\right)$$Regime 4: $({R}_{\tau}\ge \text{}0.5)$$${\tau}_{zul}=24.4\cdot {1.04}^{x}\left(MPa\right)$$${M}_{\tau}$ is the mean stress sensitivity, the exponent x in the above equations is queried from the below notch detail table:
The grinding bonus and the thickness factor is applied to the calculated fatigue limit for longitudinal and transverse and just the thickness factor to the calculated shear fatigue limit.Curve G H x 0 9  Utilization Factor Calculation
U_{T} = σ_{TA} / σ_{Tzul}
U_{L} = σ_{LA} / σ_{Lzul}
U_{τ} = τ_{A} / τ_{zul}
 Resultant Utilization Calculation

$${U}_{R}=\sqrt[2]{{({U}_{T})}^{2}+{({U}_{L})}^{2}+{({U}_{\tau})}^{2}+({U}_{T}X{U}_{L})}$$