Dear all,
In order to obtain conservative results, temperature factor would not be taken into account. The analysis should be performed using the so-called "Cold Elasticity (Young) Modulus" of the basic material.
However, since thin walled piping components are involved, pressure factor should be generally considered. As both B31 piping Codes and speciality literature stipulates, for thin walled elbows/bends, the internal pressure load reduces the cross section distortion/ovalisation during the in-plane and/or out-plane bending process.
Therefore, internal pressure load reduces both the bending SIFs and bending flexibility (i.e. the elbow/bend becomes more rigid).
Therefore, for an accurate analysis purpose, internal pressure load should be taken into account and the geometrical nonlinear behaviour of the elbow/bend should be considered (i.e. the material still behaves linearly/elastically, but the geometrical nonlinear options should be involved during Finite Element Analysis).
For conservative and simplified approach, you may perform a linear-elastic analysis and you can ignore pressure loading effect for Stress Intensification Factors (i.e. in-plane and out-plane SIFs) assessment purpose.
However, the elbow/bend flexibility factor cannot be properly estimated using this simplified (full linear) approach because the actual value would be lower than the theoretical value obtained by linear-elastic analysis.
Regards,
_________________________
Dorin Daniel Popescu
Lead Piping Stress Engineer