Mr. Flames,

You could follow Mr. Dave's recommendation as an approximation. Add a few extra 'mm' to your model to make it work. Dont worry about the little bit of difference in the model dimensions. If your system is not strictly stiff, it will not make a dramatic difference in the results, but you will be able to get a feel of the stresses for starters. Dont forget to apply a suitable SIF at the intersection with the bend.

If stresses are significantly high, you should seek a FEA program to check the local stresses.

Best Regards,