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friction hill

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Published: 01 December 2009
Fig. 3 Friction hill in plane-strain compression with a constant coefficient of friction. Source: Ref 14 More
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005456
EISBN: 978-1-62708-196-2
..., the forces (or stresses) are balanced on the differential element, with friction taken as uniform at the tool-slab boundary. This results in a friction hill that is linear for the friction factor model and nonlinear for the coefficient of friction model, with the die pressure increasing from the open...
Image
Published: 01 December 2009
Fig. 2 Coefficient of friction according to the formulae for cold rolling of carbon steel by Hill, Roberts, and Ekelund. Source: Ref 43 More
Series: ASM Handbook
Volume: 22B
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.hb.v22b.a0005540
EISBN: 978-1-62708-197-9
... and springback analysis: the type of solution algorithm/governing equation and the type of element. The article provides information on various models for material yield criteria. finite element methods friction sheet metal forming springback analysis SOFTWARE PROGRAMS continue to provide...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006410
EISBN: 978-1-62708-192-4
..., the frictional force, and, thus, the die pressure must also increase, leading to the development of the so-called friction hill ( Fig. 12b ). Consequently, die pressure can be very much higher than would be expected from the yield stress of the workpiece material. One of the aims of the theory of metalworking...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009006
EISBN: 978-1-62708-185-6
... state germane to centerbursts is not developed. Second, the flow stress may be obscured by uncertain “friction-hill” effects at the sample ends. Third, the fractures are generally at the surface, and the workability of material in the interior of the workpiece may not be reflected. On the other hand...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002372
EISBN: 978-1-62708-193-1
... If στδ and στδ crit can be experimentally determined, then the designer can use this value as a design guide. Note that both the slip amplitude and the shear stress depend on the coefficient of friction (with opposite responses) and the imposed loading. Analysis by Nowells and Hill ( Ref 15...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004017
EISBN: 978-1-62708-185-6
... at the interface, it barrels, and the friction-hill pressure distribution is created over the interface. The inhomogeneity of deformation throughout the cross section leads to a dead zone at the tool interface and a region of intense shear deformation. A similar situation can arise when the processing tools...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003316
EISBN: 978-1-62708-176-4
... amplitude and the shear stress depend on the coefficient of friction (with opposite responses) and the imposed loading. Analysis by Nowell and Hills ( Ref 15 ) of this work provided a theoretical justification and a possible method for predicting “initiation” (or nucleation) time based on the total...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0009224
EISBN: 978-1-62708-176-4
... values. Basically, the hardness test is a measure of the resistance a material offers to plastic flow. The simple compression test, Fig. 2 , provides another measure of resistance to plastic flow that is more widely used in design analysis. If friction is kept to a low value on the die faces...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009007
EISBN: 978-1-62708-185-6
... with Hill's variational principle ( Ref 12 ), the authors developed the following expression for the uniaxial compressive flow stress. This assumes a von Mises yield criterion and an interface friction factor m = 3 τ i / σ 0 where τ i is the interfacial shear (friction) component...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003279
EISBN: 978-1-62708-176-4
.... Moore D.F. , Principles and Applications of Tribology , Pergamon Press , Oxford , 1975 , p 62 – 85 Selected References Selected References • Bhushan B. and Gupta B.K. , Handbook of Tribology , McGraw-Hill , 1991 • Friction and Wear Testing Source Book , ASM...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009003
EISBN: 978-1-62708-185-6
... at the interface, it barrels, and the friction-hill pressure distribution is created over the interface. The inhomogeneity of deformation throughout the cross section leads to a dead zone at the tool interface and a region of intense shear deformation. A similar situation can arise when the processing tools...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009009
EISBN: 978-1-62708-185-6
... Deformation , J. Inst Met. , Vol 93 , 1964–1965 , p 38 – 46 18. Male A.T. , Variations in Friction Coefficients of Metals During Compressive Deformation , J. Inst. Met. , Vol 94 , 1966 , p 121 – 125 19. Avitzur B. , Metal Forming Processes and Analysis , McGraw-Hill , 1968...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006385
EISBN: 978-1-62708-192-4
... by the pressing stem. Because of a phenomenon called friction hill, where the pressure becomes large for thin sections, it is impossible to extrude all of the material from square dies; in any case a thin layer of material (butt) remains in the container. The butt may consist only of the dummy block material...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006422
EISBN: 978-1-62708-192-4
... along the contact length is significant. A sense of this variation can be obtained from the plot in Fig. 7 . Pressure reaches a maximum at the neutral point, and trails off on either side to the entrance and exit points, which is called friction hill. Relative movements within the arc of contact...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003265
EISBN: 978-1-62708-176-4
.... (b) Shearing, when L / D > 2.5. (c) Double barreling, when L / D > 2.0 and friction is present at the contact surfaces. (d) Barreling, when L / D < 2.0 and friction is present at the contact surfaces. (e) Homogenous compression, when L / D < 2.0 and no friction is present...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003030
EISBN: 978-1-62708-200-6
... Abstract Tribology is the science and technology of interacting surfaces in relative motion or, the study of friction, wear, and lubrication. This article focuses on friction and wear processes that aid in the evaluation and selection of materials, for polymers and some composites used...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006398
EISBN: 978-1-62708-192-4
..., and the practical aspects and solutions in the friction, lubrication, and wear mitigation of sliding bearings. The lubrication of bearings includes thick-film lubrication, thin-film lubrication, and boundary lubrication. The article concludes with a discussion on the effects of material elasticity...
Series: ASM Handbook
Volume: 22B
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.hb.v22b.a0005542
EISBN: 978-1-62708-197-9
...  Kinetic energy   Thermal energy  Dissipation 12 Euler number Eu = Δ p ρ V 2  Frictional pressure loss  2 ×  velocity head  Fluid friction in conduits 11 Fanning fraction factor f = D ′ Δ p 2 ρ V 2 L = 2 τ w...