Experimental and numerical investigation of deformation characteristics during tube spinning

The primary objective of this study is to predict the geometric shape and thickness change during multi-pass tube spinning to a hemispherical shape. A computationally efficient, axisymmetric finite element model of the tube-spinning experiments is described. Uniaxial tensile tests are conducted for the development of the material model. The post-necking hardening curve is identified using a hybrid experimental-numerical method and represented by a combined Swift-Voce model. For validation of the finite element model, spinning experiments are performed at room temperature on thin-walled cylinders of 6061-O aluminum alloy. The experiments are interrupted after spinning passes 2, 4, 6, and 8 and the shape and thickness are measured. Also, local strain measurements on the final spun tube (pass 8) are accomplished by a scribed grid. By comparing the predictions to the experiments, good agreement is obtained on the shape, thickness, and strain evolution in multi-pass spinning. The deformation mechanism of this process is described by analyzing the history of plastic strain on an element of the numerical model.