FEM Numerical Simulation and Experimental Investigation on End-Forming of Thin-Walled Tubes Using a Die

Abstract

Thin-walled tubes are applied in several industrial areas, as heat exchangers, shock absorbers, preforms to other metal forming processes, etc. In this study an experimental and theoretical investigation is performed involving tube end expansion, reduction and inversion processes using a die. The parameters that govern each process are investigated. A brief description of each process and a summary of the state of art are presented. The material employed in the experimental tests is an AISI 1010 carbon steel and all the work is carried out at room temperature. The theoretical investigation is done using FEM software QFORM 3D, version 4.1.5. In order to feed the software with realistic data stress-strain curves for the material were obtained by means of compression tests and the tribological conditions at the contact interface between the tube and the tools was estimated by means of ring compression method. The investigation on the tube end-forming processes focused mainly on understanding modes of deformation and on establishing formability limits for each of them. The results show that processes for end-forming of thin-walled tubes are successful only within a compact range of process parameters.

Theoretical model of a metal tube under inversion over circular dies

“…The successful inversion of a tube mainly depends on its material properties [10], the friction coefficient between tube and die [6,7], and the dimension of the die [11][12][13][14]. In general, a tube made of the ductile material over a die with low friction coefficient is easier to be inverted.…”

Investigation of circular aluminium tube expansion by rigid die as energy absorbers using digital image correlation technology

“…16 Experimental, finite element analysis and theoretical investigations of the expansion of circular tubes by rigid dies have been performed to study the factors affecting the absorption of impact energy. 17,18 Different researchers have presented different types of methods like reduction/contraction of thinwalled tubes, 19,20 barrelling, 21 End-forming 22 and some new design methods 23,24 to improve energy absorption characteristics of cylindrical metal tubes. Plastic deformation of metallic tubes occurred in different mechanical processes [1][2][3] have been studied by researchers to understand the deformation and value of strain at which the deforming tube fails or splits using strain gauges.…”