Regularities of mechanical behavior of steel 40Cr during the postcritical deformation of specimens in condition of necking effect at tension

Abstract

The work is devoted to the experimental study of mechanical behavior regularities of the structural steel 40Cr under postcritical deformation of specimens in conditions of strain localization formation in the form of neck during extension. The results of testing specimens cut from the initial samples with a neck are given. Various levels of preliminary postcritical deformation of initial samples are implemented. Using a noncontact 3D video system for recording displacement and strain fields of Vic 3D Correlated Solutions, based on the digital images correlation technique, the displacement and strain fields in the gauge length of both the original specimens with the neck and after the groove were recorded in two different schemes to eliminate geometrical heterogeneity. On the base of obtained results, the stiffness and strength of 40Cr steel were evaluated in a necked specimen at various stages of postcritical deformation. It is shown that the material in the peripheral areas of the gauge length of the sample is in a strengthened state, which does not depend on the degree of previously achieved postcritical deformation, and the strength of the material in the neck-forming zone on the initial specimens is thereby increased.

Spatial-Time Inhomogeneity Due to the Portevin-Le Chatelier Effect Depending on Stiffness

“…This work considers the failure as a result of the stability loss of inelastic deformation processes [9][10][11][12]. The theoretical and experimental study of the basic laws of post-critical deformation makes it possible to predict conditions of destruction of deformable bodies and analyze possibilities for controlling destruction.…”

Experimental Study of Postcritical Deformation and Failure of Steels at High Temperature

“…Получены аналитические и численные решения краевых задач, иллюстрирующие реализацию резервов несущей способности и повышения живучести конструкций и тел с трещинами с учетом закритического деформирования материалов [14-17]. В связи с тем что закритическое поведение металлов связано с развитыми пластическими деформациями, особое внимание уделяется теоретическому и экспериментальному изучению процессов локализации деформаций, сопровождающихся формированием шейки в рабочей части образца [18][19][20][21][22].…”

Deformation and failure of carbon fiber composite specimens with embedded defects during tension-torsion test

“…Delamination, inappropriate bonding, inappropriate compacting, cracks, air holes or blow holes [3] have a technology-related origin and refer to different material discontinuities. L A need to timely reveal operational damages and technological defects requires a prompt control of states of structures and their consequent repairs aimed at service life extension [4][5][6][7][8][9][10]. The use of embedded optical fibers with Bragg gratings for the analysis of mechanical behaviour and evaluation of material damage is of interest at this time in the field of monitoring the state of structural elements made from composite materials [11][12][13][14][15][16][17].…”