Influence of the Residual Welding Phenomena on the Dynamic Properties of a Two-Meter Long Tube with 64 Non-Symmetrical Brackets Welded on a Helical Path

Welded elements of a two meter long tube is considered. The welded structure rotates with 100rad/sec. The non- symmetrical brackets are connected to the tube through by the welds of a curved trajectory that consists of circumferential parts and arbitrary curved part on a shaft surface and disposed on the tube in a helical sequence. The objective of the study was to explore the axis and hoop stress distribution on the shaft tube and its influence on the dynamic properties of a welded structure. Sample with one element welded to the shaft tube first was studied. Three approaches were used. Temporal and residual stresses and strains were first obtained by means of moving heat source and by means of solving simplified thermomechanical problem assuming weld laying on being simultaneous along the weld path. Cooling process was important in both methods. Third approach is an own method based on shrinkage forces notion which implementation needs only strength analysis formulation. Its correctness and applicability to the case of weld paths under study was checked. The residual welding deformations obtained by all methods were then compared with the deformations of samples welded in manufacturing conditions.