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.

Stress patterns on implants in prostheses supported by four or six implants: a three-dimensional finite element analysis.

Abstract: Purpose Using the three-dimensional finite element method (FEM), this study compared the biomechanical behavior of the "All-on-Four" system with that of a six-implant-supported maxillary prosthesis with tilted distal implants. The von Mises stresses induced on the implants under different loading simulations were localized and quantified. Materials and methods Three-dimensional models representing maxillae restored with an "All-on-Four" and with a six-implant-supported prosthesis were developed in three-dimensional design software and then transferred into FEM software. The models were subjected to four different loading simulations (full mouth biting, canine disclusion, load on a cantilever, load in the absence of a cantilever). The maximum von Mises stresses were localized and quantified for comparison. Results In both models, in all loading simulations, the peak stress points were always located on the neck of the distal tilted implant. The von Mises stress values were higher in the "All-on-Four" model (7% to 29%, higher, depending on the simulation). In the presence of a cantilever, the maximum von Mises stress values increased by about 100% in both models. Conclusions The stress locations and distribution patterns were similar in the two models. The addition of implants resulted in a reduction of the maximum von Mises stress values. The cantilever greatly increased the stress.

The yield-point loads of singly-notched pin-loaded tensile strips

Abstract: P lane stress and plane strain yield-point loads have been calculated for single-edge notched strips when tensile loading is applied through pins. These yield-point loads are lower than those for fixed-grip loading, and the percentage drop is larger in plane stress than in plane strain. The calculations were required for assessing various creep and fatigue crack propagation tests. Excellent agreement was found between experimental yield-point loads and the plane stress calculations based on the von Mises yield criterion. However, no such agreement was found when further tests were carried out on doubleedged notched specimens. Possible reasons for this discrepancy are discussed. The plane strain calculations may also be used for the ‘double cantilever bend’ specimen by a simple substitution.

A unified bifurcation analysis of sheet metal forming limits

Abstract: The purpose of this study is to determine analytically the orientations of localized necks occurring in sheet metal forming processes, and obtain the corresponding forming limit diagrams (FLDs). In addition to the force equilibrium condition as adopted by other researchers, we include the moment equilibrium in this study. The shear terms due to the perturbation are found to vanish inside the localized neck of a region of deformation. This simplifies the two-dimensional problem to a one-dimensional problem. Furthermore, it is found that there are only three possible orientations for the initiation of a localized neck, i.e., two principal directions and one zero extension direction (which applies only to negative strain ratio deformations). A special case study using the von Mises yield criterion is also presented in this paper. Predictions from our unified analysis matches with the results of Hill, R., 1952, On Discontinuous Plastic States, With Special Reference to Localized Necking in Thin Sheets, J. Mech. Phys Solids, 1, pp. 19-30. For the negative strain ratio regime (left-hand side of the FLDs), and with the results of Storen, S., and Rice, R., 1975, Localized Necking in Thin Sheets, J. Mech, Phys, Solids, 23, pp. 421-441. For the positive strain ratio regime (right hand-side of the FLD). When the localized neck is assumed to be in the zero extension direction for the negative strain ratio deformation, deformation theory and flow theory of plasticity give the same limit strains, and a unified solution to the limit strain is obtained. This solution is independent of the specific yield criterion used.