Evaluation of friction in upsetting

Tan, Xiao

doi:10.1007/s11740-010-0287-5

Cited by 7 publications

(3 citation statements)

References 33 publications

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“…The provided graph is somewhat artificial as in reality the friction coefficient changes in the process of compression and differs along the lateral direction of contact area [8,18]. Nevertheless, the obtained results (see Figure 5) allow supposing weak influence of the friction coefficient on the value of the tool displacement (less than 8%).…”

Section: Discussing the Resultsmentioning

confidence: 96%

Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

Murashov

Власов

2018

MATEC Web Conf.

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Friction has a substantial influence on the metal forming at upsetting of cylindrical aluminum specimens. The finite element method is often used to investigate this problem. This paper aims to reveal possible numerical errors and obstacles related to the 3D finite element solution of the problem. The calculation results for the proposed numerical 3D-model are compared with the experimental data. The influence of friction is demonstrated and a good agreement on the tool displacement is obtained. The features of the numerical solution of the problem in the ANSYS finite element software are shown.

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Section: Discussing the Resultsmentioning

confidence: 96%

Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

Murashov

Власов

2018

MATEC Web Conf.

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“…Deng [12] also proposed a new friction testing method, the T-shape upsetting-extruding process employing a rectangular blank, for evaluating the friction conditions during the rib-web part-forming process. Tan [13] proposed a dynamic friction model in which friction depends on both the time rate of strain and normal pressure to predict contact stresses in cylinder upsetting. In addition to these, many investigations have proceeded to explore other aspects [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Simulation and Experiment Study on Cone End Billet Method in Upsetting Billet with a Large Height-to-Diameter Ratio

Fan,

Liu,

Liu

et al. 2023

Applied Sciences

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A novel upsetting method, called Cone End Billet Upsetting (CEBU), is proposed in this paper to control bulging during the upsetting of large height-to-diameter ratio (LHDR) billets. This new upsetting method is mainly characterized by prefabricating a conical shape at the billet end, which aims to reduce the friction effect between the billet end and the anvil. In order to validate CEBU, the metal flow characteristics during upsetting of LHDR billets with traditional upsetting (TU) and CEBU were analyzed and compared by the finite element method. Experiments were also carried out to examine the deformation characteristics and microstructure of pure copper samples. The results show that, compared with TU, CEBU has a great advantage in restraining bulging and enhancing the compaction effect of upsetting. Meanwhile, bulging can be eliminated in CEBU with a 50% reduction ratio. In addition, aided by the cone end, the metal flow is no longer sensitive to the friction effect at the billet end. From the point of view of restraining bulging, a small taper angle is necessary prior to use. Furthermore, to avoid instability deformation, the height-to-diameter ratio of the billet should be below 3.0. CEBU is effective in suppressing the generation of bulging, but it also increases the pre-forming process for the end of the billet. The study on CEBU in this article is under laboratory conditions, and exploring the industrial application of CEBU will be the focus of our future research.

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“…Friction between the platens and the workpiece during metal forming can be indirectly measured during the test to simulate industrial processes. Tan 16 proposed a dynamic friction model in which the friction depends on both strain rate and normal pressure and employed the model to predict contact stresses in disc-upsetting. The model, however, does not account for barrelling and assumes a cylindrical profile which limits its applicability to real tests and processes.…”

Section: Introductionmentioning

confidence: 99%

A comprehensive experimental and numerical study of foldover onset and growth during the barrelling compression test

Khoddam

Mansourinejad

Mirzakhani

et al. 2022

Advances in Mechanical Engineering

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Foldover is a common, yet complex, transient boundary condition in several ‘metal forming processes’ including the barrelling compression test (BCT). The onset of foldover during BCT is comparable to that of necking in the tensile test. However, its role in flow curve identification has been ignored in the current literature. Methods to detect and measure its onset and growth during the processes are also not available. We propose three methods to identify the onset of foldover and measure its progress with deformation. These are conducted together with case studies of BCT to have a fundamental understanding of the onset and growth of foldover in the test and more general cases. Experimental and numerical methods are developed to accomplish this based on (1) direct measurement using tracing points, (2) energy-based and (3) geometry-based indirect measurements. These outline the required supplementary data and allow proper detection of the onset. In the first method, the migration of tracing points from the free surface to the platen-sample interface, simulated numerically, is monitored and measured visually. The second method employs the load-stroke data to calculate the total power input to the deforming system. In the third method, a criterion has been derived to detect the onset of foldover by monitoring the geometry of the sample profile during the test and comparing it to a reference quadratic profile. The observations and outputs of each method are compared and discussed.

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Evaluation of friction in upsetting

Cited by 7 publications

References 33 publications

Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

Simulation and Experiment Study on Cone End Billet Method in Upsetting Billet with a Large Height-to-Diameter Ratio

A comprehensive experimental and numerical study of foldover onset and growth during the barrelling compression test

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