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.

Comparison of the biomechanical effects of pertrochanteric fixator and dynamic hip screw on an intertrochanteric femoral fracture using the finite element method

Abstract: Background This study was conducted to examine and compare the pertrochanteric fixator (PTF) and dynamic hip screw (DHS). Methods AnsysWorkbench, a commercial finite element based program, was used to investigate the biomechanical parameters of femoral fractures and implants. The human femoral model was scanned and a femoral intertrochanteric fracture was created. Von Mises stress, von Mises strain, and shear and deformation forces on the upper and lower parts of the fracture line; and the von Mises stress, von Mises strain parameters of the screws and implant bodies during axial loading were calculated and compared. Results It was determined that the magnitude of displacement forces along the fracture line was lower in PTF. Regarding the von Mises stress and von Mises strain values on the implant bodies, the DHS body had higher levels compared with the PTF body. Conclusion This study demonstrated that PTF is more favorable than DHS for early axial loading and ambulation. Copyright © 2014 John Wiley & Sons, Ltd.

Laser hole cutting into Ti-6Al-4V alloy and thermal stress analysis

Abstract: Laser hole cutting into Ti-6Al-4V alloy is carried out. Temperature and stress fields during the cutting process are predicted using the finite element code. Temporal variation of surface temperature in the region close to the kerf edge is monitored by a thermocouple and compared with the predictions. The residual stress formed in the cutting region is obtained from the XRD technique and compared with the predictions. The morphological changes around the kerf surfaces are examined incorporating optical and scanning electron microscopes. It is found that von Mises stress attains slightly higher values at the top circumference as compared to that corresponding to the bottom circumference of the hole cut. The prediction of temperature variation agrees well with the thermocouple data. The residual stress predicted also agrees with the results of the XRD technique.

Elastic–ideally plastic beams and Prandtl–Ishlinskii hysteresis operators

Abstract: We consider a model for one-dimensional transversal oscillations of an elastic-ideally plastic beam. It is based on the von Mises model of plasticity and leads after a dimensional reduction to a fourth-order partial difierential equation with a hysteresis operator of Prandtl-Ishlinskii type whose weight function is given explicitly. In this paper, we study the case of clamped beams involving a kinematic hardening in the stress-strain relation. As main result, we prove the existence and uniqueness of a weak solution. The method of proof, based on spatially semidiscrete approximations, strongly relies on energy dissipation properties of one-dimensional hysteresis operators.

Plastic incompatibility stresses and stored elastic energy in plastically deformed copper

Abstract: The X-ray diffraction method and theoretical model of elastoplastic deformation were used to examine the residual stresses in polycrystalline copper. To this end, the {2 2 0} strain pole figures were determined for samples subjected to different magnitudes of tensile deformation. Using diffraction data and the self-consistent model, the tensor of plastic incompatibility stress was found for each orientation of a polycrystalline grain. Crystallographic textures, macroscopic and second-order residual stresses were considered in the analysis. As a result, the distributions of elastic stored energy and von Mises equivalent stress were presented in Euler space and correlated with the preferred orientations of grains. Moreover, using the model prediction, the variation of the critical resolved shear stress with grain orientation was determined.