6.2: Cross-Section Behaviour {NEN 3650} [CHCKNEN]

Perform cross-section calculations and NEN-checks

General description:

Through this design function deformations and stresses are calculated in specified cross-sections of the pipeline. Cross-sections are located at the mid-sections of elements.

If the NEN 3650 norm option is selected in design function 1 (Project Setup) a dropdown-list becomes enabled which allows a selection between "Mohr", "Tresca", "Von Mises" and "Uniaxial". Stresses will be calculated according to the selected option. The unit stresses are the result of the calculated stresses divided by the applicable stress correction factor from NEN 3650 (see below) and the yield stress(es) of the pipe material defined in table ISTROP (design function 3.1). For detailed information see description of output data tables NENSMAX and NENSTRS.

Calculations according to Mohr, Tresca, Von Mises or Uniaxial are performed similar to design function 6.2, only the stress components are determined using standard weighing factors according to the NEN 3650 rules. Moreover maximum and detailed summated and principal stresses are provided in output tables TSTRMAX, TSTRESS, MSTRMAX and MSTRESS similar to design function 6.2 without application of any correction or weighing factor to make yield ellipse analysis possible.

Function description:

The function calculates the unit check stresses in specified cross-sections and abs(max/min) results are stored in the output data table NENSMAX. One dataline per cross-section specified. Detailed data over the circumference of the cross-section are contained in the output data table NENSTRS. This table only contains results of the last cross-section calculated. At the start of a new cross-section the NENSTRS table is cleared and during the calculations on the new cross-section filled with the detailed data of that new section.

The calculated radial deformations of the cross-section(s) are similarly collected in output tables RMAXNEN and RDPLNEN. Moreover maximum and detailed summated and principal stresses are provided in output tables TSTRMAX, TSTRESS, MSTRMAX and MSTRESS to make yield ellipse analysis possible.

If detailed data are required from each cross-section to be analysed, it is advised to perform this sub-function separately for each cross-section using the unlock-functionality of this sub-function.

Overall results of previous calculations are accumulated in the output data tables of this sub-function until this function is set back. In that case all output data tables are cleared.

Explanation of the check stresses Sp, Sv:pm and Sv

 

Sp :

the hoop check stress is calculated according to NEN3650 Rules Stress correction factor is 1.1 (*)


Sv:pm :

the primary (membrane) stress due to primary loads. Only stress components with ..U.. identification are considered. The stress is reported if 1) there are only force-induced loads specified and 2) the pipeline does not follow soil settlements at (pile) supports below ground or the pipeline lies on supports above ground.

Stress correction factor is 1.0 (*)


Sv :

the primary + secondary (membrane + wall bending) stress due to primary and secondary loads. All stress components are considered. The stress is always reported. Stress correction factor is 0.647 if ReT=Re (*) (In input table ISTROP).
Sv is checked against Re.


(*) ref:

NEN 3650-2:2012 appendix D.3.1 (and) table D.4.


H6303, last changed: 14/09/2016

See also:

Input data table overview

Output data table overview

Design function errors, warnings and messages