Joining by die-less hydroforming with outer pressurization

The aim of this knowledge transfer project is to extend the process limits of joining by inner pressurization by reversing the forming direction (outer pressurization). Current investigations include the analytical derivation of a process window. Based on the plastic deformation of the outer joining partner, the elastic springback of the inner joining partner is restricted. This causes an interference pressure in the joining zone. The model enables the calculation of a minimum fluid pressure at which a force-fit joint occurs. Moreover, the calculation of a maximum fluid pressure is possible. This calculation indicates that no significant increase in the interference pressure can be observed. Besides the experimental validation of the analytical model, the numerical analysis of further process parameters as well as the influence of form-fit elements on the interference pressure are essential components of upcoming investigations.