平板による円管の1ないし2方向横圧縮の弾塑性解析 : J2FおよびJ2Gによる厳しい変形の有限要素法解析

概要

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Uni-lateral and bi-lateral elastic-plastic compressions of a circular cylinder with three different wall thicknesses by flat plates are numerically analysed by the Finite Element Method (FEM). J_2-flow theory (J2F), and J_2-Gotoh's corner theory (J2G) which was previously proposed by one of the authors are used as the constitutive equations. In the case of uni-lateral compression, the cylinder is compressed up to a completely flattened shape, which is considered a kind of plastic forming process. The deformed shapes and the compressive force are predicted better by J2G than by J2F. The spring-back behaviours are also analysed by imposing unloading process during deformation. The deformation process in the compression of a ring (plane stress state) and a spherical shell (axi-symmetric state) is also analysed. In the case of bi-lateral compression, the process is considered a kind of square-shell forming. In its final stage, the cylinder deforms into a completely unexpected shape which could be thought of as a square shell reinforced with ribs. The J2G allows the process to proceed at a lower compressive force than that for J2F. The effect of n-value (the strain-hardedning exponent) on the deformation pattern is also discussed.
一般社団法人日本機械学会の論文
1990-09-25