von Mises yield criterion

About: von Mises yield criterion is a research topic. Over the lifetime, 4374 publications have been published within this topic receiving 82642 citations. The topic is also known as: Von Mises stress.

A three-dimensional viscoelastic constitutive model of solid propellant considering viscoelastic Poisson's ratio and its implementation

Abstract: A three-dimensional viscoelastic constitutive model of solid propellant grains incorporating with viscoelastic Poisson's ratio is proposed. To apply the new constitutive equations in the commercial finite element software MSC. Marc, a fully explicit numerical algorithm is developed. Two examples are presented to illustrate the viscoelastic behavior of solid propellant grains under thermal cycling and ignition pressurization loading, respectively. The finite element analysis results show that the Von Mises strain response is safer and more conservative for propellant with viscoelastic Poisson's ratio, while the Von Mises stress response is more dangerous than those for propellant with elastic Poisson's ratio. In analyzing ignition pressurization, the Von Mises strain and Von Mises stress along the interface of solid rocket motor have a similar distribution law, regardless of viscoelastic and elastic Poisson's ratios. Thus viscoelastic Poisson's ratio of solid propellant should be taken into account for better understanding the viscoelastic behavior of solid propellant grains.

Hierarchical models for failure analysis of plates bent by distributed and localized transverse loadings

Abstract: The failure analysis of simply supported, isotropic, square plates is addressed. Attention focuses on minimum failure load amplitudes and failure locations. von Mises’ equivalent stress along the plate thickness is also addressed. Several distributed and localized loading conditions are considered. Loads act on the top of the plate. Bi-sinusoidal and uniform loads are taken into account for distributed loadings, while stepwise constant centric and off-centric loadings are addressed in the case of localized loadings. Analysis is performed considering plates whose length-to-thickness ratio a/h can be as high as 100 (thin plates) and as low as 2 (very thick plates). Results are obtained via several 2D plate models. Classical theories (CTs) and higher order models are applied. Those theories are based on polynomial approximation of the displacement field. Among the higher order theories (HOTs), HOTsd models account for the transverse shear deformations, while HOTs models account for both transverse shear and transverse normal deformations. LHOTs represent a local application of the higher order theories. A layerwise approach is thus assumed: by means of mathematical interfaces, the plate is considered to be made of several fictitious layers. The exact 3D solution is presented in order to determine the accuracy of the results obtained via the 2D models. In this way a hierarchy among the 2D theories is established. CTs provide highly accurate results for a/h greater than 10 in the case of distributed loadings and greater than 20 for localized loadings. Results obtained via HOTs are highly accurate in the case of very thick plates for bi-sinusoidal and centric loadings. In the case of uniform and off-centric loadings a high gradient is present in the neighborhood of the plate top. In those cases, LHOTs yield results that match the exact solution.

Yield of Inconel 718 by Axial-Torsional Loading at Temperatures up to 649°C

Abstract: An experimental program has been implemented to determine small offset yield loci for the nickel-base superalloy In conel 718 (IN718) under axial-torsional loading at elevated temperatures. Initial and subsequent yield loci were determined for solutioned IN718 at 23 and 454°C and for aged (precipitation-hardened) IN718 at 23 and 649°C. The shape of the initial yield loci for solutioned and aged IN718 agrees well with the von Mises prediction. However, in general, the centers of initial yield loci are eccentric to the origin due to a strength-differential (S-D) effect that increases with temperature. Subsequent yield loci exhibit kinematic and distortional hardening, and solutioned IN718 shows a weak cross effect. This work demonstrates that it is possible to determine yield surfaces for metallic materials at temperatures up to at least 649°C using multiple probes of a single specimen. The experimental data are first of their kind for a superalloy at these temperatures and will enable a better understanding of multiaxial material response.