二軸応力制御による薄肉管材の塑性不安定解析

概要

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A finite element analysis of thin-walled tube which is simultaneously subjected to axial load and internal pressure is conducted. As for constitutive law, visco-plastic model is adopted. The present problem can be assumed in quasi-static state although the employed equation is described as rate form. Therefore an iteration solving method is utilized and a solution satisfying the equilibrium equation can be obtained. Axial load and internal pressure have to be independently controlled so that the ratio of longitudinal and circumferential stresses could be kept constant. To enable this, a novel arc-length method with two different loading modes is proposed. In the method, the ratio between longitudinal and circumferential stresses is controlled as an additional constraint condition. Plastic instability condition of thin-walled tube under combined loading is also presented. A numerical example demonstrates that the proposed method can keep the stress ratio constant through the analysis and evaluate the maximum loading points of thin-walled tube under combined loading.
社団法人日本機械学会の論文
2004-10-25