A Study on the Criterion for Membrane/Shell Mixed Element and Analysis of Sheet Metal Forming Problem

J. Ocean Eng. Technol. 1998;12(2):57-64.

Jeong, Dong-Won;Yang, Gyeong-Bu;

Cheju National University;Cheju National University;

박막/쉘 혼합요소를 이용한 박판성형 해석과 박막/쉘 판별조건에 관한 연구

정동원;양경부;

제주대학교;제주대학교;

Keywords: Elastic-Plastic Finite Element Method, Membrane/Shell Mixed Element, Plane-Strain, Bending Strain, Criterion

핵심용어: 탄소성 유한요소법, 박막/쉘 혼합요소, 평면-변형, 굽힘변형률, 판별조건

Abstract

This study is concerned with criterion for membrane to shell conversion in two-dimensional elastic-plastic finite element analysis using membrane/shell mixed element. It is well known that in the sheet metal forming some parts of the sheet deform under almost pure stretching (membrane) conditions, whereas other parts in contact with sharp tooling surfaces can develop significant bending strains. The membrane analysis has a short computational time however, in the membrane analysis the bending effects can not be condidered at all. On the other hand, the shell analysis allows the consideration of bending effects, but involves too much computational time. So Onatel),2), Yang et al3),4) developed the membrane/shell mixed element. Onate introduced the energy ratio parameter and Yang et al introduced the ratio of thickness to radius of curvature as the criterion. In the present study we propose a new criterion by using the angle between both side elements in the nodal point.