摘要：Solid mechanics, which includes the theories ofelasticity and plasticity, is a broad discipline, with experi-mental, theoretical, and computational aspects [1]. Thetheory of yield plasticity does not fully satisfy experimen-tal results. Zilinskaitė and Ziliukas in [2] presented a the-ory of general relation between stresses and deformation inelastic-plastic bodies and indicated the importance of innermaterial processes. A mathematical model for two-layeraxially loaded cylindrical bars is presented by Partaukas,Bereisis [3]. The dynamic overloading and influence ofkinetics on steel fracture and yield is discussed by Chau-sov, Pylypenko [4]. Dependence of column deformationson bending and axial forces is nonlinear if yielding stressesare attained in some cross-sections of the column. The ap-proximate plastic-hinge approach for steel frames is pre-sented by Powell, Chen [5], Gong [6, 7]. A method forelasto plastic large-deflection analysis with plastic hingesat midspan and two ends is proposed by Chen and Chan[8]. The empirical approximation dependences are depictedby Xu et al [9]. All these graphs are similar one to anotherand display only principle characteristics of real depend-ence.
