Abbas Niknejad - Mechanical Engineering Department, Yasouj University, P.O. Box: ۷۵۹۱۴-۳۵۳, Yasouj, Iran
Seyed Ghaem Amirhosseini - Mechanical Engineering Department, Yasouj University, Yasouj, Iran
Nader Setoudeh - Materials Engineering Department, Yasouj University, P.O. Box: ۷۵۹۱۴-۳۵۳, Yasouj, Iran

In this article, a new theoretical model of plastic deformation of the nosing process is introduced and based on the analytical model, some theoretical relations are derived to predict the absorbed energy by the circular metal tubes during the forming process versus the axial displacement. During the forming process, circular metal tubes are transformed to the nozzles with the semi-spherical-nosed. Then, some circular brazen tubes were prepared and tested using a semi-spherical die to verify the theory. Comparison of the theoretical predictions and the corresponding experimental measurements reveals that mechanical behavior and plastic deformation of empty tubes have a good agreement with the theoretical model and predicted energy-displacement diagrams by the theoretical formula have a good correlation with the corresponding experimental curves and it proves verity of the theory. Also, the present theory shows that the absorbed energy during the nosing process is dependent on the material type; diameter and wall thickness of the tubes and it is independent of the initial tube length. Also, the effects of polyurethane foam-filler and the PVC Teflon-filler were investigated on the process, experimentally.

Absorbed Energy, Circular tube, Metal forming, Nozzle, Plastic deformation