Method of Acquisition of True Stress-Strain Curves over Large Strain by the Tensile Test and its Finite Element Analysis, and Tensile Test Device using it

摘要

A method for obtaining a true deformation rate-true stress strain curve against a high deformation rate by using a tensile test and a finite element analysis is provided to develop a finite element analysis program and an exclusive tensile test-related finite element analysis program simultaneously and to provide the true deformation rate-true stress strain curve to a user rapidly and accurately. A method for obtaining a true deformation rate-true stress strain curve against a high deformation rate by using a tensile test and a finite element analysis includes a step of obtaining a standard deformation hardening index and standard strength modulus from a result of the tensile test and deciding a test elongation degree between elongation degrees after necking is generated; a step of computing the test elongation degree after analyzing the tensile test by using a standard deformation rate-stress curve; a step of setting an initial condition for a repeat improving operation; a step of performing the repeat improving operation; a step of analyzing the tensile test by using a complete tensile test analysis model and information about moving stress of a material which is defined by the initial condition for the repeated improving operation; a step of checking a convergence condition by comparing a tensile load tested value with a predicted value of the test elongation degree, and finishing the repeated improving operation as the tested value and the predicted value converge; a step of calculating and substituting a representative deformation degree value and computing the tensile load, when the tested value and the predicted value do not converge; and a step of obtaining a value of stress by linear-interpolating the representative deformation degree value at the initial condition of the repeated improving operation.