Strain Rate Distribution During Experimental Metal Rolling

1962 ◽  
Vol 84 (1) ◽  
pp. 81-88 ◽  
Author(s):  
K. S. Yajnik ◽  
J. Frisch

Plastic deformation in commercially pure lead strips during torque-free rolling was investigated. The experimentally determined slip-line field was compared with the theoretical solution of a similar problem and was found to be different, having a plastic-rigid boundary with inflection points at the entrance section. It was observed that plastic deformation occurred well ahead of the initial contact point between the strip boundaries and the roll surfaces.

1967 ◽  
Vol 9 (1) ◽  
pp. 1-10 ◽  
Author(s):  
W. B. Palmer

Plastic flow and tool forces were observed as an orthogonal tool cut slowly into an inclined plane of En 9 steel. A slip-line field is constructed which represents the observed flow, and on the basis of the theory of plasticity for work-hardening material estimates of stress are consistent with observed tool forces.


Author(s):  
M V Srinivas ◽  
P Alva ◽  
S K Biswas

A slip line field is proposed for symmetrical single-cavity closed-die forging by rough dies. A compatible velocity field is shown to exist. Experiments were conducted using lead workpiece and rough dies. Experimentally observed flow and load were used to validate the proposed slip line field. The slip line field was used to simulate the process in the computer with the objective of studying the influence of flash geometry on cavity filling.


1989 ◽  
Vol 111 (2) ◽  
pp. 260-264 ◽  
Author(s):  
P. Lacey ◽  
A. A. Torrance ◽  
J. A. Fitzpatrick

Most previous studies of boundary lubrication have ignored the contribution of surface roughness to friction. However, recent work by Moalic et al. (1987) has shown that when asperity contacts can be modelled by a slip line field, there is a precise relation between the friction coefficient and the asperity slope. Here, it is shown that there is also a relation between the friction coefficient and the normal pressure for rough surfaces which can be predicted from a development of the slip line field model.


Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan

This chapter is concerned with the formulations and solutions for plane plastic flow. In plane plastic flow, velocities of all points occur in planes parallel to a certain plane, say the (x, y) plane, and are independent of the distance from that plane. The Cartesian components of the velocity vector u are ux(x, y), uy(x, y), and uz = 0. For analyzing the deformation of rigid-perfectly plastic and rate-insensitive materials, a mathematically sound slip-line field theory was established (see the books on metal forming listed in Chap. 1). The solution techniques have been well developed, and the collection of slip-line solutions now available is large. Although these slip-line solutions provide valuable insight into deformation modes and forming loads, slip-line field analysis becomes unwieldy for nonsteady-state problems where the field has to be updated as deformation proceeds to account for changes in material boundaries. Furthermore, the neglect of work-hardening, strain-rate, and temperature effects is inappropriate for certain types of problems. Many investigators, notably Oxley and his co-workers, have attempted to account for some of these effects in the construction of slip-line fields. However, by so doing, the problem becomes analytically difficult, and recourse is made to experimental determination of velocity fields, similarly to the visioplasticity method. Some of this work is summarized in Reference [2]. The applications of the finite-element method are particularly effective to the problems for which the slip-line solutions are difficult to obtain. The finite-element formulation specific to plane flow is recapitulated here.


1987 ◽  
Vol 29 (8) ◽  
pp. 557-564 ◽  
Author(s):  
Shang-Xian Wu ◽  
Yiu-Wing Mai ◽  
Brian Cotterell

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