DNV OS-C201-WSD Weld Strength (2011)

An offshore standard DNV OS-C201-WSD Weld Strength (2011) verifies structural stability for each structural member (weld). Weld connections (section 9) is implemented.

https://rules.dnvgl.com/docs/pdf/DNV/codes/docs/2011-04/Os-C201.pdf

Warning:

Eta 0 - basic usage factor that can be found in Table E1, section 2 of the standard is replaced with the respective load safety factor.

dnvosc201_basic_usage_factors

To add the standard execute Standard - DNV - DNV -OC201-WSD Weld Strength (2011) from the main menu. Alternatively, use the Standard context menu:

dnvosc201

By default, all welds that match following criteria are included into selection but can be changed by pressing .

Weld is included in calculations if it is:

1. Straight with the tolerance of 3 degrees;

2. Double-symmetric - weld is formed by 2 planes that are perpendicular to each other with the tolerance of 5 degrees;

Preview weld elements that are not verified press Button_preview_all_not_supported_welds.

Preview selected weld elements by pressing .

If welds are not recognized press to run the Weld Finder tool.

Note: In results only welded parts are calculated. The rest of the parts will not contain results.

Press Button_set_correlation_factor to set a Correlation factor (Beta_w):

Beta_w factor is obtained from Table C3, section 9 and depends on the material type:

dnvosc101_correlation_factor

If Include geometrical check option is ON, an extra check with the minimum/maximum weld length and throat thickness will be added to the standard:

Press to set formulas for the check:

It is possible to select 3 predefined types of bounds and custom:

  • Eurocode 3 - EN 1993-1-8, chapter 4.5.1 (2) and 4.5.2 (2);
  • AISC - ANSI/AISC 360-10, Table J2.4;
  • AWS - AWS D1.1:2010, chapters 2.4.2.1, 2.4.2.3, 2.5.4, table 5.8;
  • Custom - define all bounds manually. Tip for formulas is shown below:
  • Remove 'Tip:' and set an 'input value in model units' to make the formula correct.

    Result check will contain all included parameters and overall parameter that defines if all bounds pass:

    LimitsOK parameter returns 0 if all limits are OK and 12345678 otherwise.

    Gamma_M - material resistance factor for plated structures is a constant value (=1.15) and used in calculations to check base material strength.

    Formulas use Yield Stress and Tensile Strength from materials. It is important to set these values for each material. The number of materials with zero values are displayed:

    materials_with_yield_and_tensile

    If count > 0 then press to edit parameters:

    Checks are created automatically and divided into few parts:

    • Dimensions checks. Geometrical parameters weld area, elastic section modulus, etc.
    • Stress checks. Total weld throat stresses at the start and at the end of the weld. Weld Force Summation Tool is used to get summarized grid point forces at the weld nodes.

    T|| = shear design stress (in the plane of the throat) parallel to the axis of the weld (equal to X direction in the check);

    σ⊥= normal design stress perpendicular to the throat (equal to Y direction of the check);

    T⊥ = shear design stress (in the plane of the throat) perpendicular to the axis of the weld (equal to XY direction of the check);

    Example of the check for point T1:

    • Utilization factors. . Total utilization factors, base material check, and overall utilization factor checks.

    Calculation Method defines the way of results calculations/presentation - per weld part or per element. They are described in Force Summation tool.