Theory of single point incremental forming of tubes

Cristino, V.A.M.; Magrinho, J.P.; Centeno, Gabriel; Silva, M.B.; Martins, P.A.F.

doi:10.1016/j.jmatprotec.2020.116659

Cited by 19 publications

(16 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To conclude, it is worth mentioning that the main reason why the Hosford yield criterion was not utilized in this work was due to its unavailability in the commercial finite element computer program utilized by the authors. Hill's 48 yield criterion was not considered as well because of the difficulty in obtaining the Lankford's coefficient at 45 • in a tube, and because Cristino et al [16] achieved good analytical estimates of material flow neglecting anisotropy.…”

Section: Figurementioning

confidence: 99%

“…In view of the aforementioned work, recent developments in incremental tube expansion, reduction, wall grooving and hole flanging using a single point hemispherical tool by Wen et al [14] and Movahedinia et al [15] raise the question of whether their deformation mechanics and formability limits remain the same as those of conventional tube forming processes. The answer to this question was firstly addressed by Cristino et al [16], who presented an analytical model based on membrane analysis for tube expansion by single point incremental forming (hereafter referred to as incremental tube expansion). The model reveals the main differences between conventional and incremental tube expansion in terms of stress/strain states and damage accumulation to explain the greater formability of incremental tube expansion compared to that of conventional tube expansion with a rigid tapered conical punch.…”

Section: Introductionmentioning

confidence: 99%

“…The analytical model of Cristino et al [16] is based on a rigid, perfectly plastic tube material and assumes near-proportional (equal biaxial stretching) experimental strain loading paths in principal strain space to facilitate algebraic treatment.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tube Expansion by Single Point Incremental Forming: An Experimental and Numerical Investigation

Suntaxi

Centeno

Silva

et al. 2021

Metals

Self Cite

View full text Add to dashboard Cite

In this paper, we revisit the formability of tube expansion by single point incremental forming to account for the material strain hardening and the non-proportional loading paths that were not taken into consideration in a previously published analytical model of the process built upon a rigid perfectly plastic material. The objective is to provide a new insight on the reason why the critical strains at failure of tube expansion by single point incremental forming are far superior to those of conventional tube expansion by rigid tapered conical punches. For this purpose, we replaced the stress triaxiality ratio that is responsible for the accumulation of damage and cracking by tension in monotonic, proportional loading paths, by integral forms of the stress triaxiality ratio that are more adequate for the non-proportional paths resulting from the loading and unloading cycles of incremental tube expansion. Experimental and numerical simulation results plotted in the effective strain vs. stress triaxiality space confirm the validity of the new damage accumulation approach for handling the non-proportional loading paths that oscillate cyclically from shearing to biaxial stretching, as the single point hemispherical tool approaches, contacts and moves away from a specific location of the incrementally expanded tube surface

show abstract

Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tube Expansion by Single Point Incremental Forming: An Experimental and Numerical Investigation

Suntaxi

Centeno

Silva

et al. 2021

Metals

Self Cite

View full text Add to dashboard Cite

show abstract

“…Incremental forming is a flexible process. Incremental forming does not use die and can be used for a wide variety of product shapes [6][7][8]. Spinning is a typical incremental forming method [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…Elongation and twisting of the tube could be suppressed by increasing the feed pitch or feeding the ball die towards the chucked end. 6 The smaller diameter of the steel ball made it possible to process a larger diameter reduction ratio. 7…”

mentioning

confidence: 99%

Ball Spin Forming for Flexible and Partial Diameter Reduction in Tubes

Hirama

Ikeda

Gondo

et al. 2020

Metals

View full text Add to dashboard Cite

This paper proposed a new ball spin forming equipment, which can form a reduced diameter section on the halfway point of a tube. The effects of forming process parameters on the surface integrity and deformation characteristics of the product were investigated. The proposed method can reduce the diameter in the middle portion of the tube, and the maximum diameter reduction ratio was over 10% in one pass. When the feed pitch of the ball die was more than 2.0 mm/rev, spiral marks remained on the surface of tube. Torsional deformation, axial elongation and an increase in thickness appeared in the tube during the forming process. All of them were affected by the feed pitch and feed direction of the ball die, while they were not affected by the rotation speed of the tube. By sending the ball die towards the fixed part of the tube or by increasing the feed pitch, torsional deformation and elongation decreased, and the amount of thickening increased. When the tube was pressed perpendicularly to the axis without axial feed, a diameter reduction ratio of 21.1% was achieved without defects using a ball diameter of 15.9 mm. The polygonization of the tube was suppressed by reducing the pushing pitch. The ball spin forming has a high advantage in flexible diameter reduction processing on the halfway point of the tube for producing different diameter tubes.

show abstract