MECHANISM OF IMPROVEMENT OF FORMABILITY IN PULSATING HYDROFORMING OF T SHAPE TUBES

The effect of oscillation of internal pressure on the formability and shape accuracy of the products in a pulsating hydroforming process of T- haped parts was examined by the finite element simulation and experiment. The mechanism of improvement of formability by the oscillation of internal pressure was investigated. It is shown that the local thinning was prevented by oscillating the internal pressure because the protrusion is formed gradually by the prevention of the sharp bulging. It was found that pulsating hydroforming is useful in improving the formability and shape accuracy in the T-shape hydroforming operation. On the other hand, the effects of the amplitude and the number of cycles of pressure per unit punch stroke in the pulsating T-shape hydroforming on formability and corner filling are examined. It is shown that the small number of cycles of pressure and large amplitude increase the improvement of formability, whereas large number of cycles of pressure and small amplitude increase the corner filling of die and shape accuracy in T-shape hydroforming of tubes.

کلیدواژه ها:

Pulsating hydroforming ، T-shape ، FE simulation ، Formability