An evaluation of through - thickness deformation mechanisms in single point incremental sheet forming using a dual - level finite - element mode

• Autorzy: Essa K. , Hartley P.

Warianty tytułu

PL

Ocena metodą dwupoziomową elementów skończonych zmian mechanizmu odkształcenia na grubości w jednopunktowym przyrostowym kształtowaniu blach

• Języki publikacji: EN

Abstrakty

EN

Single point incremental forming (SPIF) is a process with the capability to form complex geometries using a tool of very simple geometry, without the need for a matching die. At present, through-thickness modes of deformation and the existence of through-thickness shear are not clear. The objectives of this report are firstly, to establish a computational methodology to study the deformation mechanism of SPIF and secondly, to provide a clear description of the deformation modes that take place through the sheet thickness. The methodology is, in essence, a multi-level approach, although in this example only two levels are necessary. In this paper, a 3-D implicit finite-element (FE) model of the complete sheet being formed, with two elements through the thickness and a second-level FE model of a smaller segment of the sheet, with seven elements through its thickness, are used in a dual-level approach. The results show that the full model is capable only of exploring the principal characteristics of the deformation, normal strains and the final product geometries. The second-level model demonstrates a capability to predict more accurately the deformation modes through the sheet thickness and shows the influence of tool friction and diameter on the through-thickness shear strains. A combination of bending, stretching and thinning modes of deformation in addition to through thickness shear is found. The results obtained provide a more complete description of through-thickness deformation mechanisms. 

PL

Jednopunktowa przyrostowa metoda kształtowania blach (ang. single point incremental forming - SPIF) jest procesem umożliwiającym uzyskiwanie skomplikowanych kształtów przy zastosowaniu prostych narzędzi. Nie jest potrzebna zgodność kształtu narzędzia i wyrobu. Stosowane obecnie modele tego procesu nie określają jednoznacznie zmian odkształcenia i ścinania na grubości blachy. Cele niniejszej pracy to po pierwsze opracowanie metody analizy mechanizmów odkształcenia w SPIF, a po drugie dostarczenie opisu schematów odkształcenia występujących w tym procesie wzdłuż grubości blachy. Zastosowano metodę podejścia wielopoziomowego, chociaż w rozważanym zadaniu potrzebne były tylko dwa poziomy. Dla kształtowanej blachy wykorzystano model implicit 3D na bazie metody elementów skończonych (MES), z dwoma elementami na grubości. Dla małego wycinka blachy zastosowano model MES drugiego poziomu z siedmioma elementami na grubości. Wyniki wykazały, że pełny model umożliwia ocenę tylko głównych charakterystyk odkształcenia, czyli odkształceń normalnych i kształtu wyrobu. Model drugiego poziomu przewiduje dokładniej schemat odkształcenia na grubości blachy i umożliwia ocenę wpływu tarcia i średnicy na rozkład odkształceń postaciowych wzdłuż grubości. Dodatkowo możliwy był opis połączonego wpływu zginania, rozciągania i pocienienia. W konsekwencji uzyskane wyniki dostarczają pełniejszego opisu mechanizmów odkształcenia na grubości blachy.

Słowa kluczowe

EN

Asymmetric incremental sheet forming; single point incremental forming; finite element analysis; through-thickness deformation modes; shear strain

• Wydawca: Wydawnictwa AGH
• Czasopismo: Computer Methods in Materials Science
• Rocznik: 2012
• Tom: Vol. 12, No. 1
• Strony: 37--50
• Opis fizyczny: Bibliogr. 28 poz., rys.

Twórcy

autor

Essa K.

autor

Hartley P.

• School of Mechanical Engineering, College of Engineering and Physical Sciences University of Birmingham. Edghaston, Birmingham, B15 2TT, UK,

Bibliografia

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