Estimation of mechanical expansion stroke and force and effects of processing parameters on expanding quality for giant ring

ABSTRACT

Mechanical expansion is the key process in the manufacture of giant metallic ring. The mechanical expansion process of a 10-m-class aluminium alloy ring is taken as the research object in this paper. First, based on the springback theory of small curvature plane bending, the springback ratio formula is derived for the wall thickness centre-line of the ring cross section after unloading, and the mechanical expansion stroke model is established by the mould displacement compensation method. Then, a calculation method for mechanical expansion force is proposed by considering the friction between the mould arc surface and the ring inner wall. Moreover, a finite element model (FEM) is established to simulate the mechanical expansion process of a 10-metre-class aluminium alloy ring using MSC_Marc. The results show that the model proposed in this paper reduces the dimension error of the ring after unloading by 9.19%, and increases the calculation accuracy of the mechanical expansion force by more than 30% under different friction coefficients. Furthermore, the effects of processing parameters, centre angel of the mould segment, relative radius of the mould segment, fillet radius of the edge mould segment, ovality, expansion rate and friction coefficient on the fabricated ring quality are numerically investigated.

KEYWORDS:

• Mechanical expansion stroke
• mechanical expansion force
• springback theory of small curvature plane bending
• mechanical expansion processing parameters
• MSC_Marc
• giant metallic ring

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported National Major Science and Technology Projects of China[2015ZX04005-011].

Notes on contributors

Zhengqiang Zhu

Zhengqiang Zhu, PhD student, his current research interests include structural analysis and evaluation, modeling and control of metal forming process.

Yibo Li

Yibo Li received the Ph.D. degree from the School of Mechanical & Electrical Engineering, Central South University. He is currently an Associate Professor at School of Mechanical & Electrical Engineering, Central South University. His current research interests include multi-disciplinary numerical simulation, structural analysis and evaluation, modeling and control of metal forming process.

Minghui Huang

Minghui Huang, born in 1963, is currently a professor and a PhD candidate supervisor at State Key Laboratory of High Performance Complex Manufacturing, Central South University, China. His main research interests include machine design and manufacturing, design theory, fault diagnosis, and digital manufacturing.