Friction at high normal pressures

Wanheim, Tarras

doi:10.1016/0043-1648(73)90074-4

Cited by 95 publications

(31 citation statements)

References 3 publications

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“…Shaw et al [5] explained in more detailed that the ratio of real contact area to apparent area increases with pressure and approaches unity asymptotically. Wanheim [6] theoretically and experimentally verified the relationship between friction stress and normal stress. Childs [7] obtained similar results using the slip-line fields, as did Chivers et al [8] using the upperbounds and whose results were discussed by Childs [9].…”

Section: Introductionmentioning

confidence: 93%

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Evaluation of friction coefficient using indentation model of Brinell hardness test for sheet metal forming

Leu¹

2011

J Mech Sci Technol

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This work presents an indentation model of the Brinell hardness test, which is a rigid ball-deformable plane contact model (RB-DP model), to elucidate the sliding friction mechanism of sheet metal forming. In the proposed model, the friction force can be defined as a combination of shear (shearing effect) and plough (ploughing effect) forces. The real contact area ratio α is determined from the RB-DP model under sliding condition. Moreover, the lateral contact area ratio / c r A A can be specified as a function of the real contact area ratio α . Based on Meyer's law and Hertz contact problem, the maximum contact area ratio u α , a limiting condition of the real contact area ratio α , can be described as a function of the strain hardening exponent n. Additionally, a limiting condition applies: the strain hardening exponent n must be less than 0.64 in the present model. The present friction model reveals that the friction coefficient d μ is a function of strain hardening exponent n, the real contact area ratio α and the maximum contact area ratio u α . The calculated friction coefficient d μ agrees with the published experimental results.

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Section: Introductionmentioning

confidence: 93%

“…Wanheim [6] was the first to present the theoretical relationship between the normal pressure and the real contact area between two surfaces in contact under high normal pressure. In this work, contact between two rough surfaces is idealized as the RB-DP model.…”

Section: Real Contact Area Ratio αmentioning

confidence: 99%

Evaluation of friction coefficient using indentation model of Brinell hardness test for sheet metal forming

Leu¹

2011

J Mech Sci Technol

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“…Nowadays there are numerous friction models used in metal forming, such as Amontons-Coulomb friction model (application examples by von Karman [1] and Kudo [2]); the constant friction model (reviewed for example by Schey [3]); the general friction model by Wanheim and Bay [4][5][6][7]; the absolute constant friction stress model by, for example, Orowan [8], Alexander [9], Tan et al [10]; Levanov friction model [11]; Chen and Kobayashi model [12]; the empirical friction model by Bay and his coworkers [13,14]. Reynolds equation has also been used to model friction for different metal forming processes by Wilson and his co-workers, e.g., plane strain forging [15,16], and sheet forming [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…x b j j, where R is the deformed radius. Alternatively, Bay and Gerved [31] have suggested that friction stress for the slip zone can be calculated by the general friction model [4][5][6][7]:…”

Section: Introductionmentioning

confidence: 99%

Evaluation of friction in upsetting

Tan

2010

Prod. Eng. Res. Devel.

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Distributions of contact stresses at the neutral point in metal forming are very hard to be properly predicted due to the complex interface situation and lack of suitable friction models. In this paper, the dynamic friction model in which the friction depends on both time rate of strain and normal pressure has been applied to predict contact stresses in cylinder upsetting. Case studies have shown that the predicted results agreed with the experimental data chosen from literature. By comparing with two other friction models, the dynamic friction model seemed to give a better solution.

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“…The dependence of Ar/An on load was studied by Pullen and Williamson [3] using a rough aluminium surface compressed by a hard flat punch. The persistence behaviour of the asperities was analyzed theoretically by Childs [4] and Wanheim [5] using the slip line field method and Chivers et al [6] and Wilson and Sheu [7] using an upper-bound theorem. Most of the experiments used a model asperity where a surface roughness is modeled as a uniform array of wedge-shaped ridges.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Component Thickness on the Flattening of Surface Asperities

Jamari

Schipper

2015

Jurnal Teknologi

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Graphical abstract AbstractAn experimental investigation of a deformable flat rough surface being in contact with a hard smooth ball indenter was presented to evaluate the effect of thickness on the flattening of surface asperities. A novel method to determine the asperities flattening was deployed. The method uses a matching and stitching technique for analyzing the 3D measurement surface data. Two different materials of flat surfaces, aluminium and brass, were used. Results were presented for very thin and thick specimens, showing that there is no effect of thickness on the deformation degree of the surface asperities. Comparisons were made with the published models for predicting the deformation degree of the contacting surface and the results obtained confirm very well the model. Keywords: Contact mechanics, indentation, thickness, deformation, asperity AbstrakSebuah penyelidikan eksperimental dari permukaan kasar datar yang bisa terdeformasi di kontakkan dengan sebuah indentor bola yang halus dan keras, disajikan untuk mengevaluasi efek ketebalan terhadap deformasi plastis asperiti permukaan. Sebuah metode baru untuk menentukan besarnya deformasi plastis asperiti diberdayakan. Metode ini menggunakan teknik pencocokan dan pengabungan untuk menganalisis data pengukuran permukaan 3D. Dua bahan permukaan datar yang berbeda, aluminium dan kuningan, digunakan dalam studi ini. Hasil penelitian disajikan dengan spesimen yang sangat tipis dan specimen yang sangat tebal, yang menunjukkan bahwa tidak ada pengaruh ketebalan terhadap tingkat deformasi plastis asperiti permukaan. Perbandingan dilakukan terhadap model yang telah terpublikasi untuk memprediksi tingkat deformasi plastis permukaan yang berkontak. Hasil-hasil menunjukkan bahwa model yang digunakan terkonfirmasi dengan baik.Kata kunci: mekanika kontak, indentasi, ketebalan, deformasi, asperiti

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Friction at high normal pressures

Cited by 95 publications

References 3 publications

Evaluation of friction coefficient using indentation model of Brinell hardness test for sheet metal forming

Evaluation of friction coefficient using indentation model of Brinell hardness test for sheet metal forming

Evaluation of friction in upsetting

The Effect of Component Thickness on the Flattening of Surface Asperities

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