Contact mechanics of zinc-coated steel sheets

Mulki, Hasan; Mizuno, Takaji

doi:10.1016/0043-1648(96)07200-6

Cited by 8 publications

(8 citation statements)

References 8 publications

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“…Additionally, the slight dependency of the supporting effect on the lubricant viscosity in case of pyramid P32 (Fig. 4b) would be in good agreement with the results from Mizuno [23] that the entrapment of lubricant which is in favor of a reduction of friction increases with increasing lubricant viscosity. For pyramid P5, where hardly any influence of lubricant on the appearance of the topography is detectable, other mechanisms seem to be predominantly responsible for the supporting effect of the lubricants.…”

Section: Surface Characterizationsupporting

confidence: 82%

Basic investigations on boundary lubrication in metal forming processes by in situ observation of the real contact area

Weidel

Engel

Merklein

et al. 2009

Prod. Eng. Res. Devel.

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In metal forming processes tribology plays a significant role for process feasibility and tool lifetime. Boundary and mixed lubrication conditions are predominant in metal forming processes. Hence the appearing real contact area which is mainly influenced by the topography of tool and workpiece has a major impact on friction conditions. For an improved understanding of friction at the interface between tool and workpiece, the flattening behavior of idealized asperities under boundary lubrication conditions is investigated by applying a translucent tool. Various liquid lubricants have been used. It has been revealed that the usage of certain lubricants leads to higher resistance of the asperity against flattening which would be in favor of reduced friction. Topography analysis and finite element simulations have been performed in order to get more insight into the mechanisms leading to this effect. The findings have been transferred to real topographies by micro upsetting tests with ground surfaces.

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Section: Surface Characterizationsupporting

confidence: 82%

Basic investigations on boundary lubrication in metal forming processes by in situ observation of the real contact area

Weidel

Engel

Merklein

et al. 2009

Prod. Eng. Res. Devel.

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“…In the literature, analytical models [7][8][9][10][11] are proposed to determine the real area of contact for coated sheet under a normal load. Recently, a semi-analytical normal load contact model is proposed by Shisode et al [11].…”

Section: Model Descriptionmentioning

confidence: 99%

“…The real area of contact for a given loading condition or a combination of loads is generally determined either by dedicated experiments or physics based models. There are numerous models and experimental studies available for normal load flattening for uncoated [4][5][6] and coated sheets [7][8][9][10][11]. In a typical sheet metal forming process, the sheet surface is deformed due to a contact pressure (normal load), sub-surface strain in the sheet metal, and sliding of the tool over the sheet surface.…”

Section: Introductionmentioning

confidence: 99%

Evolution of real area of contact due to combined normal load and sub-surface straining in sheet metal

et al. 2020

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Understanding asperity flattening is vital for a reliable macro-scale modeling of friction and wear. In sheet metal forming processes, sheet surface asperities are deformed due to contact forces between the tools and the workpiece. In addition, as the sheet metal is strained while retaining the normal load, the asperity deformation increases significantly. Deformation of the asperities determines the real area of contact which influences the friction and wear at the tool-sheet metal contact. The real area of contact between two contacting rough surfaces depends on type of loading, material behavior, and topography of the contacting surfaces. In this study, an experimental setup is developed to investigate the effect of a combined normal load and sub-surface strain on real area of contact. Uncoated and zinc coated steel sheets (GI) with different coating thicknesses, surface topographies, and substrate materials are used in the experimental study. Finite element (FE) analyses are performed on measured surface profiles to further analyze the behavior observed in the experiments and to understand the effect of surface topography, and coating thickness on the evolution of the real area of contact. Finally, an analytical model is presented to determine the real area contact under combined normal load and sub-surface strain. The results show that accounting for combined normal load and sub-surface straining effects is necessary for accurate predictions of the real area of contact.

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“…Over the last few decades, since the early works on forming operations by Kudo (1960Kudo ( , 1961 and Rowe (1965), the upper bound method has been in use by a large number of investigators. Amongst those are: Fox and Lee (1989), Na and Cho (1989), Cho and Kim (1990), Mulki and Mizuno (1996), Kimura and Childs (1999), Pater (1999), Garmestani et al (2001) and Chai (2003). Later more related works on the use of upper bound method in some tenacious patterns are reported, notably, the work of Bona (2004), Es-Saheb (2004) and Moller et al (2004), as well as Ebrahimi and Najafizadeh (2004).…”

Section: Introductionmentioning

confidence: 99%

Analyses of Plane-strain Compression Using the Upper Bound Method

Es-Saheb¹,

Al-Witry²,

Albedah³

2013

RJASET

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Traditional upper bound analyses for plane-strain compression leads to low load prediction values, for a large ratio range of contact Length (L) to thickness (h). These predicted load values are based on deformation fields consisted of rigid regions separated by planes upon which discrete shear occurs. In this study, the relatively simple deformation fields consisted of odd number of triangles such like, 1, 3 and 5, are used. A general minimum solution for this class of upper bounds is derived and found to occur when the base of the center triangle (w) [= 2L/ (n+1)], where n is an odd integer ≥3. Consequently, whether still lower values would occur with this class of field when the ratio(R), of the field triangles side lengths is varied, has been systematically investigated. Thus, the upper bound loads are calculated over a wide range of the ratio (R) and the deformation field parameters. These parameters include the thickness (h) the contact Length (L) and the base of the center triangle (w). It is found that, all the minimum load values occur at unity R ratio and the minimum values of h, L and w. The minimum values obtained for hopt, Lopt and wopt are 1.466, 3.266 and 2.0 units, respectively. Also, the corresponding overall minimum optimal upper bound value found is P/2k = 1.93.

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Contact mechanics of zinc-coated steel sheets

Cited by 8 publications

References 8 publications

Basic investigations on boundary lubrication in metal forming processes by in situ observation of the real contact area

Basic investigations on boundary lubrication in metal forming processes by in situ observation of the real contact area

Evolution of real area of contact due to combined normal load and sub-surface straining in sheet metal

Analyses of Plane-strain Compression Using the Upper Bound Method

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