Joining of tubes by internal mechanical locking

This paper presents an innovative plastic deformation process for connecting two tubes by their ends. The connection is done by internal mechanical locking at room temperature and is capable of ensuring uniformity of the outer diameters of the two tubes to be joined. The range of applicability is complementary to mechanical joining based on fasteners or plastic deformation by crimping or local instability, which are known to compromise the overall appearance and aesthetics of the resulting applications and products. The presentation identifies the major process parameters and investigates their influence on the deformation mechanics and joining feasibility. The force requirements to produce the new type of joint and to detach the tubes by application of tensile loading are also analysed by means of experimentation and finite element modelling. Selected examples give support to the presentation.