Comparative Study of the Plastic Paradox based on Numerical Analysis Method of Plastic Deformation Theory in Low-Orbit Environment

Plastic paradox had been proposed in the study of elastoplastic buckling of simply supported plates in low-orbit environment. Due to the existence of plastic paradox, the study of buckling, post-buckling mechanical properties and ultimate bearing capacity of plates and shells faced greater difficulties and uncertainties. The existence of plastic paradox leads to the question of the rationality of the nonlinear finite element method using plastic deformation theory in the analysis of plate-shell structures, and also affects the elastoplastic buckling and post-buckling mechanical behavior of the steel structures, for instance, compression bars and pressure plates. Based on the comprehensive research and judgment of the existing plastic paradox research results, combined with the elastoplastic numerical analysis conclusions of the pressure bar and the pressure plate, through the secondary development of the Marc software subroutine hypler2, the constitutive relation subroutine of plastic deformation theory has been compiled to analyze the elastoplastic buckling of the simply supported plate again. By comparing the analysis results of plastic flow theory and plastic deformation theory, the analysis results show that plastic paradox does not exist. The plastic paradox is caused by the displacement shape function of the compression plate, which constrains the free plastic strain in the plastic deformation theory. (c) 2025 L&H Scientific Publishing, LLC. All rights reserved.