The work was born from the needs of a teaching company scheme that was completed through the University. It was noted that there was a need for a structured scientific approach to assist in the design and manufacture of small diameter thin walled tubes bent using the draw bending process. The research has concentrated on the prediction of two parameters that hinder the production of right first components: springback and elongation.
The prediction of springback was considered to be a linear elastic problem, in that although the tube has been permanently deformed and so undergone plastic deformation the springback parameter is the elastic release, which incurs due to the force being removed. In this way springback can be reverse engineered, utilising linear finite element code. The results from springback were qualitatively successful and indicated the effect of the major variables within the draw bending process.
For the prediction of elongation it was assumed that the majority of the elongation was caused by a shift in the neutral axis. This shift was the result of a change in the wall thickness after the bending process. A program has been produced that allows the position of the neutral axis to be calculated for small transverse slices (elements) of the tube. In this way the neutral axis can be traced throughout the complete bending process and elongation for any bend can be predicted.
The results from the research has been presented as a series of graphs, with equations derived from them. The springback results although qualitatively successful would be improved with further work. The graphs could be used in a workshop type environment, and the equations could be incorporated into machine code. Further work would include investigating the relationship between the volume of the tube and the amount of springback and elongation.
OCR method and verification notes: kathy/abstract-ocr.