Hi everyone!

I am wondering why the result forces in the bolts (axial) are not the same as calculated by hand? The simulation study I have created is a simplified version of more complex design and I am looking for the way how to validate the results and make sure that the design boundaries are OK (restrains). I have got two parts of a pressure cylinder bolted together through flanges. I have modelled up 3 connectors per pair only just to minimise the computation time to achieve any results. The internal pressure is equal to 2 MPa and the area of the pressure acting on the bolts in theirs axial direction is equal 0.02 m2. Getting the hand calculations done by multipling the pressure and area, the total result force is equal 40 000N wheras the actual reaction force is 10 times less than calculated. The axial force in bolts are not equal and tends to be the greatest in the mid span of flange.

Could anybody point me where the problem is?

Is there any way of extracting bolt axial force, shear force and bending moment by using free body force tool? I have tried this and it worked on a single part simulation (without introducing no penetration contacts and bolts) but I wasn't sure where the point to be referenced for bending moment calculations should be made. Thanks!

I set this up with only three points constrained, one fixed ll ways the others planar. Symmetry or face restraints may be appropriate if this is a section of a much longer piece.

Stress and displacement is of generally uniform pattern.

Bolt forces are nearly equal and symmetric. Each side totals over 15,900 to an expected 16,000 lbf.