The experimental investigation of fragile strength parameters of plastic material in conditions of an irregular three-dimensional tension (TDT)

摘要

In 1911 von Karman has shown with experiment that in conditions of three-dimensional pressure brittle materials get plasticity. Many authors assume that in conditions of TDT plastic materials get fragility. Engineers and designers, who use the equivalent tension method and criteria von Mises and Tresca, do not take into account the getting of fragility. Many researchers have noticed that these criteria forecast over strength in a conditions of three-dimensional tension. Hence these criteria do not give the correct, but some time give dangerous results. It 50-th of last century M.Schnadt has proposed an integral theory of strength in the form of a “Diagram of Material” as a possible solution. But his theory was not proved experimentally. Authors have prepared and performed the experiment on a plastic material. As the result the fragile strength parameters of steel A-36 were obtained and the M.Schnadt diagram boundary curves for certain material were defined. Experimental results and defined M.Schnadt diagram are shown in given work.