Yield limit dependence of titanic alloy VТ14 from the stress state parameters


  • N N. Tormakhov Институт механики им. С.П.Тимошенко Национальной академии наук Украины, Киев, Ukraine




stress, yield limit, stress state mode, tensor, deviator


The stress state mode has influence on the yield limit of construction materials that causes the necessity of account of this phenomenon at determination of this material resource. A quantitative characterization of the stress state can be given by means of two parameters which describe, accordingly, by the volume constituent of tensor and stress deviator mode. Influence of the volume constituent of tensor is characterized by the stress triaxiality parameter, and stress deviator mode - by the Lode parameter, Lode corners or normalized third deviatoric stress invariant. In paper is proposed the yield limit dependences as second degree polynomials of the stress state parameters. These dependences are concreted for the titanic alloy VТ14 on the basis of experiments with the loading of tubular specimen by axial force and intrinsic pressure. Supposed, that the stress state in the wall of specimen corresponded to what exists in on his middle surface. At the calculation of the stress intensity not only axial and circuitous but also radial stresses token into account, that resulted in reduction of divergence of yield limits at the different stress state from 12,4 to 10,2 %. The results of calculations showed that the best from the polynomials is equation with contain members: the first degree from both stress state parameters, multiplicity of these parameters and second degree from the stress triaxiality parameter. From the point of view of statistical meaningfulness appeared the best equation that as stress deviator parameter contained the module of the normalized third deviatoric stress invariant. The level of meaningfulness of this equalization on the criterion of Fisher and constants on the criterion of Student exceeded a size 94 %. The application of the proposed regression equation for describing the dependence of the yield strength of a titanium alloy VT14 on parameters of the stress state type makes it possible to make fuller use of the resource capabilities of this material.


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How to Cite

N. N. Tormakhov, “Yield limit dependence of titanic alloy VТ14 from the stress state parameters”, Mech. Adv. Technol., vol. 84, no. 3(84), pp. 91–97, Dec. 2018.



Original study