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 sensitivity analysis and optimization of automobile body frame consisting of rectangular tubes

Abstract: At conceptual design stage, beam element is extensively used to create the frame structure of automobile body, which can not only archive the accurate stiffness but also reduce much computational cost. However, the stress definition of beam element is very complex so that the stress sensitivity and optimization are difficult to analytically derive and numerically program. This paper presents an solution to this problem and an application in the lightweight optimization design of automobile frame. Firstly, maximal Von Mises stress of rectangular tube is calculated by using the superposition of stress, which is together induced by the axial force, bending moments, torsional moment and shear force. Secondly, the sensitivity of Von Mises Stress with respect to size design variables: breadth, height and thickness are derived, respectively. Thirdly, an optimal criterion is constructed by Lagrangian multiplier method to solve the frame optimization with stress constraints. Lastly, numerical example of car frame proves that the proposed method can guarantee the stress of each beam element almost fully reaches at the yielding stress.

Shear mediated elongational flow and yielding in soft glassy materials

Abstract: In this work, we study the deformation behavior of thin films of various soft glassy materials that are simultaneously subjected to two creep flow fields, rotational shear flow by applying torque and elongational flow by applying normal force. The generic behavior under the combined fields is investigated in different soft glassy materials with diverse microstructures such as: hair gel, emulsion paint, shaving foam and clay suspension. Increase in the strength of one stress component while keeping the other constant not only leads to an expected enhanced deformation in its own direction, but also greater strain in the other direction. The Herschel–Bulkley model is observed to explain this behavior qualitatively. The elongational flow induced in the materials eventually causes failure in the same. Interestingly time to failure is observed to be strongly dependent not just on the normal force but also on the applied rotational shear stress. We believe that the presence of a three dimensional jammed structure, in which an overall unjamming can be induced by applying stress having sufficient magnitude irrespective of the direction, leads to the observed behavior. In addition, we observe self-similarity in the elongational as well as rotational strain–time curves corresponding to various combinations of both the fields. This observation suggests a mere shift in the time-scales involved keeping the path followed in the process unchanged. A phase diagram is also constructed for various soft glassy materials by determining different combinations of orthogonal stresses beyond which materials yield. The estimated yield stress in the limit of flow dominated by the applied tensile force on the top plate demonstrates scatter, which might be originating from fingering instability. Except this deviation, yielding is observed when the invariant of the stress tensor exceeds the yield stress, validating the Von Mises criterion.

Hole expansion of advanced high strenth steel sheet sample

Abstract: In this work, the stretch-flangeability of an AHSS steel sheet sample, TWIP1000, was investigated through the hole expansion tests. Uniaxial tension and disk compression tests were also performed to characterize the basic mechanical behaviour of the material. Then finite element simulations of the hole expansion test were carried out using ABAQUS, respectively combined with three yield criteria, Von Mises, Hill 1948 and Yld2000-2d. Finally, the simulation results were compared with experimental to evaluate the model and the effect of yield criteria.

Residual Stress Relaxation of Quasi-Statically and Cyclically-Loaded Steel Welds

Abstract: Weld fatigue strength is currently the bottleneck to designing high performance and lightweight welded structures using advanced materials. In addition to loading conditions, environmental aspects, geometrical features and defects, it has been proven that studying the influence of residual stresses on fatigue performance is indispensible. The extent of the influence is, however, a matter of discussion. In this work, residual stress behaviour in welded S355J2G3 and S1100QL steel specimens under quasi-static and cyclic loading were studied and the correlation between the relaxation of residual stress field and mechanical properties was studied. Residual stress measurements were performed using the X-ray diffraction technique. The relaxation behaviour in S355J2G3 at weld metal, weld toe and in the base metal could be described by Von Mises criteria. This was not the case for S1100QL. In the case of relaxation, it was observed that if the Von Mises stress, as a function of residual, load and mean stresses, exceeds the monotonic yield strength of the base metal, relaxation takes place. Otherwise, the internal elastic stresses remain stable regardless of the number of loading cycles and could contribute to fatigue damage.

On the elastic-plastic deformation of a rotating disk subjected to a radial temperature gradient

Abstract: Elastic–plastic stress distribution in a nonisothermal rotating annular disk is analyzed by the use of Tresca and von Mises criteria. An energy equation that accounts for the convective heat transfer with a variable heat transfer coefficient is modeled. For a given angular velocity, the steady temperature distribution in the disk is obtained by the analytical solution of the energy equation. Tresca yield criterion and its associated flow rule are used to obtain the analytical stress distributions for a linearly hardening material. A computational model is developed to analyze elastic–plastic deformations of the disk using von Mises yield criterion and its flow rule. This model incorporates Swift's hardening law to simulate linear as well as nonlinear hardening material behavior. It is shown that the stress distribution in the disk is affected significantly by the presence of the temperature gradient.