Design of a Thin Metal Product with the Developable Middle Surface from a Sheet by Parabolic Bending

2020 ◽  
Vol 986 ◽  
pp. 78-85
Author(s):  
Sergey Nikolayevich Krivoshapko ◽  
Marina Rynkovskaya ◽  
Andrey Razin
Keyword(s):  
Shell Theory ◽  
Thin Sheet ◽  
Sheet Thickness ◽  
Middle Surface ◽  
Thin Metal ◽  
Pure Bending ◽  
Technical Approach ◽  
Space Industry ◽  
Plastic Materials ◽  
Thin Metal Sheet

In the paper, the method to calculate the bending moments arising due to the process of parabolic bending of a thin metal sheet into a torso shell is offered. The problem is solved with the help of methods of differential geometry and shell theory. The possibility of manufacturing any torso product without creases and tears from a thin sheet made of plastic materials is theoretically proved. A review of experimental and theoretical works on pure bending is given. In contradistinction to the mathematical approach to bending a thin sheet into a torso shell (where the thickness of a sheet is assumed to be zero), this paper considers a technical approach taking into account the sheet thickness. It is shown that the normal stresses occurring in a thin sheet as a result of the bending can reach the yield point. On the contrary mathematical possibility to bend a sheet into a torso product, and then unbend it back into a flat position, it is shown in the paper that under certain conditions a sheet cannot be bent back to a flat sheet again due to the occurrence of plastic strains. The results of the research can be used in marine design, civil engineering, air-space industry, and other manufacturing processes.

scholarly journals Crack Initiation and Extension under Penetration of Thin Metal Sheet.

1991 ◽  
Vol 57 (539) ◽  
pp. 1495-1501
Author(s):  
Ken KAMINISHI ◽  
Motoharu TANEDA ◽  
Shunichi KAWANO ◽  
Shinji TANAKA
Keyword(s):  
Crack Initiation ◽  
Metal Sheet ◽  
Thin Metal ◽  
Thin Metal Sheet

The Propagation of Plasticity in Uniaxial Compression

1948 ◽  
Vol 15 (3) ◽  
pp. 256-260 ◽  
Author(s):  
M. P. White ◽  
LeVan Griffis
Keyword(s):  
Uniaxial Compression ◽  
Thin Sheet ◽  
High Stress ◽  
Stress And Strain ◽  
Velocity Range ◽  
Plastic Materials ◽  
The Face ◽  
Elastic Plastic Materials ◽  
The Impact ◽  
Type Of Behavior

Abstract A theoretical investigation of the mechanism of uniaxial compression impact on elastic-plastic materials is described in this paper. The method of analysis is similar in some respects to that previously given for tension impact on such materials. It is concluded that four different kinds of behavior can occur, depending upon the impact velocity. In the lowest velocity range the behavior in compression is similar to that found in tension. In this case stress and strain are propagated from the point of impact as a zone or wave front of ever-increasing length. This type of behavior ends at a velocity corresponding to the “critical” velocity found in tension impact. Within the next higher velocity range, stress and strain are propagated as a shock-type wave, or wave of very small length in which the transition from low to high stress and strain is very abrupt. At still higher impact velocities, there occurs “flowing deformation” in which the material is too weak to maintain coherency. Here there is a steady flow of the material toward and against the hammer, after which it flows in a thin sheet radially outward over the face of the hammer. The final possible state occurs at impact velocities greater than the speed of an elastic wave, so that no disturbance can escape from the hammer into the medium. Here the behavior is essentially that of a fluid, impact force being independent of strength of material.

scholarly journals Investigation of a partial, inductive short-time heat treatment of thin metal sheets integrated into the forming process

2018 ◽  
Vol 190 ◽  
pp. 12008
Author(s):  
Benjamin Clausius ◽  
Petra Maier
Keyword(s):  
Heat Treatment ◽  
Strain Hardening ◽  
Sheet Thickness ◽  
Local Strain ◽  
Single Step ◽  
Thin Metal ◽  
Recrystallization Annealing ◽  
Forming Process ◽  
Metal Sheets ◽  
Short Time

Flanging is a widespread method in the sheet metal working industry to connect same or different materials by forming. Especially the sealing technology makes high demands on the flanging process: a low sheet thickness of the inner eyelet is necessary for proper sealing. The outer edges of the neck rings are mostly manufactured by shear cutting. The quality of the cut surface and the level of the local strain hardening influence decisively the limit of the flanging process by possible cracking. This paper is focused on the dependencies of these factors regarding thin metal sheets of different materials with a thickness down to 100 μm. It could be shown that strain hardening has a stronger effect on the process limits compared to the notch effect of the sheet edges when using standard values for the clearance of the shear cutting tool. Furthermore, a process is investigated with a partial inductive short-time heat treatment of the most deformed edge area. Due to the low thickness of the material and low heat capacities related thereto, it is possible to integrate a recrystallization annealing as single step into the forming process. As a result, the strain hardening can be removed from the affected zone directly between two forming steps to increase the process limits.

Collapse of Thin Orthotropic Elliptical Cylindrical Shells Under Combined Bending and Pressure Loads

1979 ◽  
Vol 46 (2) ◽  
pp. 363-371 ◽  
Author(s):  
J. Spence ◽  
S. L. Toh
Keyword(s):  
Shell Theory ◽  
Nonlinear Boundary ◽  
Cylindrical Shells ◽  
Normal Pressure ◽  
Nonlinear Ordinary Differential Equations ◽  
Pure Bending ◽  
Finite Deflection ◽  
Shooting Technique ◽  
Theoretical Predictions ◽  
Thin Shell Theory

The elastic collapse of thin orthotropic elliptical cylindrical shells subject to pure bending alone or combined bending and uniform normal pressure loads has been studied. Nonlinear finite deflection thin shell theory is employed and this reduces the problem to a set of nonlinear ordinary differential equations. The resulting two-point nonlinear boundary-value problem is then linearized, using quasi-linearization, and solved numerically by the “shooting technique.” Some experimental work has been carried out and the results are compared with the theoretical predictions.

Through Thickness Microstructural Investigation of Temper Rolled Ferritic Steels for Thin Sheet Applications

2010 ◽  
Vol 89-91 ◽  
pp. 73-78
Author(s):  
Caroline Luis ◽  
Monique Gaspérini ◽  
Thierry Chauveau
Keyword(s):  
Thin Sheet ◽  
Sheet Thickness ◽  
Ferritic Steels ◽  
Temper Rolling ◽  
Interstitial Free ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Shear Tests ◽  
Microstructural Investigation ◽  
X Ray

This paper focuses on the analysis of the microstructure and of the texture through the sheet thickness after temper rolling of very thin ferritic steels. The study uses EBSD and X-Ray diffraction. Comparison is made between an interstitial-free (IF) steel and of some industrial low carbon ferritic steels used after ageing. The experimental results are discussed with respect to the anisotropy of the mechanical behaviour after temper rolling during simple shear tests.

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