Bend Wall Thickness Analysis

Related Topics

This analysis calculates the maximum allowable pressure for a given bend wall thickness, and conversely the minimum wall thickness for a given pressure. In addition, stress intensification factor in and perpendicular to the bend plane and maximum allowable bending moment are calculated. Allowable bending moment is calculated based on static and fatigue failure values.

Input data can be copied using the toolbar icon and  inserted into any other Start-Elements analysis by using the toolbar icon in that file.

Bend properties can also be copied between START-PROF and Start-Elements. More...

Input Data



Mill tolerance

Mill tolerance at the time of production. More...

Corrosion and wear allowance

Corrosion and wear allowance (working mill tolerance) for wall thickness. More...

Do not check internal bend wall thickness

According to RD 10-249-98 section "for extruded elbows manufactured in a closed press, or for bends manufactured on machinery with high-frequency currents and axial preload, c12 for sR1  allowance must be from 0.05s to 0.1s. c12 rof sR3 allowance is 0, and internal bend analysis is not performed.
For extruded elbows with the perpendicular weld along the middle of the elbow length, c12 rof sR3 allowance is 0, while c12 rof sR1 allowance must be from from 0.05s to 0.1s; in this case, internal elbow analysis is not performed, because this side of the elbow has a higher wall thickening than the K2 factor."

Weld pressure quality factor

Set based on standards. Can be calculated automatically by pressing . More...

Weld bending quality factor

Set based on standards. Can be calculated automatically by pressing . More...

Ambient temperature

Ambient temperature. More...

Operation temperature

Operation temperature in operation state. More...

Operation pressure, P

Operation pressure in operation state. Set for all standards except SNIP 2.05.06-85. More...

Working pressure, Pwork

Working pressure (based on standards). Set when analyzing with SNIP 2.05.06-85. More...

Service life

Piping Service life from 1 to 30 years. Used for fatigue failure analysis.

Fatigue factor

Used for fatigue failure analysis. Usually set as 1.0, but in cases of higher safety requirements can be set as 0.2, 0.15 or 0.1.

Steel grade

Pipe material from the materials database


If "pressure" is selected, allowable pressure can be calculated by setting nominal wall thickness. If "wall thickness" is selected, minimum allowable wall thickness can be calculated by setting the pressure.

In both cases, wall thickness is set as no lower than the minimum allowable based on:

For SNIP 2.05.06-85, an additional wall thickness check is performed using formula (66) section 13.16.

Wall thickness is rounded up to 0.1 mm.