Processing math: 100%

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)
Ar=Ti·Tf
  • Ti : Thickness influence represents the resultant maximum weld thickness. It varies based on the weld type. this parameter is location specific.
  • Tf : Indicates which shell thickness you need for the calculation of effective weld thickness ( a ). Valid options are t and tmin , also location specific. t = thickness of welded shell. tmin = min thickness of all connected shells.
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.
Groove Gap (b)
Gap between the two plates at the location of weld. b in Figure 1.
Groove Depth (h)
Height of the groove from the top, calculated as t - c from Figure 1.
Groove Angle (alpha - deg)
Angle of the groove/plate walls at the location of weld. a in Figure 1.
Note: Refer to Figure 1 for the groove parameters. These groove parameters have been derived from the En 15085 standard. Refer to Common Classification Parameters.


Figure 1.

Formulation

Stress Component considered for evaluation
  • σT : Transverse component perpendicular to the axis of the weld
  • σL : 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.
Calculation of the Assessment stress value (numerator in utilization formulae)
(1)
σTA (Stress Amplitude) = (σTmaxσTmin)/2

The stress amplitude is used as the numerator for the utilization calculation.

Fatigue Limit Calculation

The fatig98ue limit values ( σTzul , σLzul , and τzul ), are calculated based on the following regimes of Stress Ratio ®,

Reference: the DVS1608 regulation document section 7.2.2.

For nominal stress (longitudinal σLzul and transverse σTzul )

Regime 1: (Rσ> 1)
σzul=541.04x(MPa)
Regime 2: (   Rσ 0)
σzul=461.04x(11+Mσ1+Rσ1Rσ)(MPa)
Regime 3: (0 < Rσ< 0.5)
σzul=421.04x(11+Mσ3(1+Rσ1Rσ))(MPa)
Regime 4: (0.5  Rσ< 1)
σzul=36.51.04x(MPa)

Mτ 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, τzul ,

Regime 2: (1  Rτ 0)
τzul=281.04x(11+Mτ1+Rτ1Rτ)(MPa)
Regime 3: (0 < Rτ< 0.5)
τzul=26.51.04x(11+Mτ3(1+Rτ1Rτ))(MPa)
Regime 4: (Rτ 0.5)
τzul=24.41.04x(MPa)

Mτ is the mean stress sensitivity, the exponent x in the above equations is queried from the below notch detail table:

Curve G H
x 0 9
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.
Utilization Factor Calculation
UT = σTA/σTzul

UL = UL = σLA/σLzul

Uτ = τA/τzul

Resultant Utilization Calculation
UR=2(UT)2+(UL)2+(Uτ)2+(UTXUL)