Shakedown analysis of nozzles in the knuckle region of torispherical heads under multiple thermo-mechanical loadings

•Nozzles in the knuckle region of torispherical heads are considered.•Various combinations of thermo-mechanical loading are investigated.•Interactions of two and three loadings acting simultaneously are evaluated.•The results are compared to those found in literature where available.

The load-bearing capacity of cylindrical pressure vessels closed by Klöpperböden torispherical drumheads with piping nozzle connections placed in the head's knuckle region is determined by using shakedown analysis. The pressure vessels under consideration are subjected to internal pressure, an axial force in the direction of the nozzle, in-plane bending moment at the nozzle, and temperature loading, all of which may vary independently. In particular, the interactions are investigated in several combinations of two and three of these loads, leading to two- and three-dimensional loading domains. The corresponding elastic and shakedown limits are computed based on Melan's statical shakedown theorem. The obtained results are compared to those taken from literature where available.