Showing papers on "von Mises yield criterion published in 2020"
TL;DR: In this article, the analysis on various geometric forms of connecting rod such as solid type, shell type has been carried out using modelling package such as SOLIDWORKS and ANSYS software.
82 citations
TL;DR: The present work demonstrates that it is feasible to describe the stress-strain response of a von Mises material through a neural network model without any explicit representation of the yield function, flow rule, hardening law or evolution constraints.
77 citations
TL;DR: In this article, a phase-field model for ductile fracture is proposed to predict crack initiation, propagation, and branching, and the fracture toughness decreases due to increased plastic deformation.
70 citations
TL;DR: In this article, a nonparametric Bayesian prior for the function $f$ is devised and a Bernstein - von Mises theorem is proved which entails that the posterior distribution given the observations is approximated in a suitable function space by an infinite-dimensional Gaussian measure that has a ''minimal' covariance structure in an information-theoretic sense.
Abstract: The inverse problem of determining the unknown potential $f>0$ in the partial differential equation $$\\frac{\\Delta}{2} u - fu =0 \\text{ on } \\mathcal O ~~\\text{s.t. } u = g \\text { on } \\partial \\mathcal O,$$ where $\\mathcal O$ is a bounded $C^\\infty$-domain in $\\mathbb R^d$ and $g>0$ is a given function prescribing boundary values, is considered. The data consist of the solution $u$ corrupted by additive Gaussian noise. A nonparametric Bayesian prior for the function $f$ is devised and a Bernstein - von Mises theorem is proved which entails that the posterior distribution given the observations is approximated in a suitable function space by an infinite-dimensional Gaussian measure that has a `minimal' covariance structure in an information-theoretic sense. As a consequence the posterior distribution performs valid and optimal frequentist statistical inference on $f$ in the small noise limit.
65 citations
TL;DR: A unified yield function that is able to represent several classical failure criteria including von Mises, Drucker–Prager, Tresca, Mohr–Coulomb, Bresler–Pister and Willam–Warnke is introduced and used to solve topology optimization problems with local stress constraints.
Abstract: An interesting, yet challenging problem in topology optimization consists of finding the lightest structure that is able to withstand a given set of applied loads without experiencing local material failure. Most studies consider material failure via the von Mises criterion, which is designed for ductile materials. To extend the range of applications to structures made of a variety of different materials, we introduce a unified yield function that is able to represent several classical failure criteria including von Mises, Drucker-Prager, Tresca, Mohr-Coulomb, Bresler-Pister and Willam-Warnke, and use it to solve topology optimization problems with local stress constraints. The unified yield function not only represents the classical criteria, but also provides a smooth representation of the Tresca and the Mohr-Coulomb criteria-an attribute that is desired when using gradient-based optimization algorithms. The present framework has been built so that it can be extended to failure criteria other than the ones addressed in this investigation. We present numerical examples to illustrate how the unified yield function can be used to obtain different designs, under prescribed loading or design-dependent loading (e.g. self-weight), depending on the chosen failure criterion.
44 citations
TL;DR: It is concluded that the present FE model accurately predicts stress distribution pattern in dental implants and indicates that sensitivity of length play a more significant role in comparison with thread pitch.
43 citations
TL;DR: In this paper, the simultaneous magnetic and structural topology optimization of a transverse laminated synchronous reluctance machine rotor using a solid isotropic with material penalization (SIMP)-based approach with the globally convergent method of moving asymptotes (GCMMA) optimization algorithm is presented.
Abstract: This article presents the simultaneous magnetic and structural topology optimization of a transverse laminated synchronous reluctance machine rotor using a solid isotropic with material penalization (SIMP)-based approach with the globally convergent method of moving asymptotes (GCMMA) optimization algorithm. Magneto-structural single and multi-objective optimization formulations are presented. The single objective formulation maximizes the average torque subject to constraints on torque ripple, Von Mises stress, and compliance. The multiobjective formulation simultaneously maximizes average torque and minimizes compliance subject to constraints on torque ripple and Von Mises stress. In both optimization formulations, the electrical steel densities in the rotor mesh elements are the control variables. Including stress and compliance in the optimization formulation ensures a structurally feasible design. The design-dependent centripetal force contributed by each element in the rotor mesh is considered dependent on its density and mass. An intermediate density material issue is observed where the density of the material in a mesh element does not converge fully to air or electrical steel. This issue is addressed through the use of a thresholding mass function which forces the convergence of the mass but not the density. The two optimization formulations are compared for rotors operating at 4000 and 12 000 r/min. An initial magnetic only topology optimization is used to seed the magneto-structural topology optimization to decrease the computational time. The impact of the magnetic only seed and rotor mesh density on the optimization outcomes is also examined.
41 citations
TL;DR: A conditional generative adversarial network (cGAN) model for predicting 2D von Mises stress distributions in solid structures that can predict more accurate high-resolution stress distributions than a baseline convolutional neural network model, given various and complex cases of geometry, load and boundary conditions.
Abstract: Using deep learning to analyze mechanical stress distributions has been gaining interest with the demand for fast stress analysis methods. Deep learning approaches have achieved excellent outcomes when utilized to speed up stress computation and learn the physics without prior knowledge of underlying equations. However, most studies restrict the variation of geometry or boundary conditions, making these methods difficult to be generalized to unseen configurations. We propose a conditional generative adversarial network (cGAN) model for predicting 2D von Mises stress distributions in solid structures. The cGAN learns to generate stress distributions conditioned by geometries, load, and boundary conditions through a two-player minimax game between two neural networks with no prior knowledge. By evaluating the generative network on two stress distribution datasets under multiple metrics, we demonstrate that our model can predict more accurate high-resolution stress distributions than a baseline convolutional neural network model, given various and complex cases of geometry, load and boundary conditions.
37 citations
TL;DR: In this paper, an extended bi-directional evolutionary structural optimization (BESO) method is adopted to maximize the stiffness of geometrically nonlinear continuum structures subject to volume fraction and maximum von Mises stress constraints.
37 citations
TL;DR: In this article, a numerical simulation of the transient thermal analysis and the static structural one was performed sequentially, with the coupled thermo-structural method using the ANS.
Abstract: In this work, a numerical simulation of the transient thermal analysis and the static structural one was performed here sequentially, with the coupled thermo-structural method using the ANS...
36 citations
TL;DR: In this paper, the effect of multiaxial loading scenario on surface topography in notched samples made of high-strength steels processed by both conventional and additive manufacturing techniques was studied.
TL;DR: In this article, an ordinary state-based peridynamics to simulate plastic deformation is presented, which can simulate nonlinear-hardening plastic mode, what's more, the perfect plastic model and linear hardening plastic model can also be simulated in a simple way too.
TL;DR: In this paper, an atomic-level investigation of the correlation between elastic and structural heterogeneities and the mechanisms of shear banding in CuZr metallic glass is conducted using molecular dynamics simulations.
TL;DR: In this paper, a 3D finite element (FE) model was developed to investigate the effect of cyclic loading, which is induced by vibration during operation of in-line inspection (ILI) tools, on local stress and strain distributions and failure pressure of an X80 steel natural gas pipeline containing a corrosion defect.
TL;DR: In this article, a number of analytical strength criteria have been developed for porous materials having a Drucker-Prager solid matrix by using different up-scaling methods and a wide variety of new numerical results are then provided from finite element simulations to enlarge the comparisons.
TL;DR: In this paper, a general loading condition is considered and the rods are regarded as hyperelastic bodies composed of a homogeneous isotropic material, and the finite displacement fields and deformation gradients are derived under the hypothesis of homogeneous deformations.
Abstract: This paper deals with the equilibrium problem of von Mises trusses in nonlinear elasticity. A general loading condition is considered and the rods are regarded as hyperelastic bodies composed of a homogeneous isotropic material. Under the hypothesis of homogeneous deformations, the finite displacement fields and deformation gradients are derived. Consequently, the Piola-Kirchhoff and Cauchy stress tensors are computed by formulating the boundary-value problem. The equilibrium in the deformed configuration is then written and the stability of the equilibrium paths is assessed through the energy criterion. An application assuming a compressible Mooney-Rivlin material is performed. The equilibrium solutions for the case of vertical load present primary and secondary branches. Although, the stability analysis reveals that the only form of instability is the snap-through phenomenon. Finally, the finite theory is linearized by introducing the hypotheses of small displacement and strain fields. By doing so, the classical solution of the two-bar truss in linear elasticity is recovered.
TL;DR: This article proposes an efficient continuum topology optimization method on the basis of the design philosophy of robust fail-safe structure and develops an extended variable update scheme within the framework of Optimality Criteria method.
TL;DR: In this article, the authors applied synchrotron X-ray diffraction to study the evolution of lattice strain and stresses in both phases of pearlitic steel during a tensile test.
TL;DR: In this paper, the burst pressure of steel reinforced flexible pipe (SRFP) considering plasticity is investigated through experimental, theoretical and numerical methods, and the results obtained from the aforementioned methods are in good agreement with each other, which illustrates the accuracy and reliability of the proposed theoretical and numeric models.
TL;DR: In this paper, the applicability of von Mises yield criterion is examined firstly using experimental results and finite element analyses, and a yield function for HSSs is proposed, to essentially simulate the elastoplastic behavior of high strength steel under complex stress states.
TL;DR: The results suggest that the deformation-dependent fiber orientations need to be considered when wall strength determined from uniaxial tests are used for in vivo biomechanical analysis, and that the dispersed fiber failure criterion demonstrates a good fitting capability with the off-axis testing data.
Abstract: Accurate failure criteria play a fundamental role in biomechanical analyses of aortic wall rupture and dissection. Experimental investigations have demonstrated a significant difference of aortic wall strengths in the circumferential and axial directions. Therefore, the isotropic von Mises stress and maximum principal stress, commonly used in computational analysis of the aortic wall, are inadequate for modeling of anisotropic failure properties. In this study, we propose a novel stress-based anisotropic failure criterion with dispersed fiber orientations. In the new failure criterion, the overall failure metric is computed by using angular integration (AI) of failure metrics in all directions. Affine rotations of fiber orientations due to finite deformation are taken into account in an anisotropic hyperelastic constitutive model. To examine fitting capability of the failure criterion, a set of off-axis uniaxial tension tests were performed on aortic tissues of four porcine individuals and 18 human ascending thoracic aortic aneurysm (ATAA) patients. The dispersed fiber failure criterion demonstrates a good fitting capability with the off-axis testing data. Under simulated biaxial stress conditions, the dispersed fiber failure criterion predicts a smaller failure envelope comparing to those predicted by the traditional anisotropic criteria without fiber dispersion, which highlights the potentially important role of fiber dispersion in the failure of the aortic wall. Our results suggest that the deformation-dependent fiber orientations need to be considered when wall strength determined from uniaxial tests are used for in vivo biomechanical analysis. More investigations are needed to determine biaxial failure properties of the aortic wall.
TL;DR: In this article, the authors investigated the thermoelastic frictional contact responses of an elastic sphere sliding on an elastic layer-substrate system involving imperfect interfaces and found that a stronger discontinuity of interface displacements causes the contact pressure, temperature, and in-plane compressive stress to decrease, but the inplane tensile stress, out-of-plane (compressive and tensile) stress, and von Mises stress to increase.
TL;DR: In this paper, a state-based peridynamic microstructure model is developed to simulate the damage initiation and propagation and plastic deformation in multi-phase materials The dual-phase (DP) steel is utilized as a material example.
TL;DR: A study was carried out to evaluate the force distribution on the implant components (In-Kone® Universal) and on the peri-implant tissues subjected to loading and the obtained results are satisfactory; the distribution of forces appears optimal even on thePeri-IMplant tissues.
Abstract: The bioengineering and medical and biomedical fields are ever closer, and they manage to obtain surprising results for the development of new devices. The field of simulations and studies in silica has undergone considerable development in recent years, favoring the advancement of medicine. In this manuscript, a study was carried out to evaluate the force distribution on the implant components (In-Kone® Universal) and on the peri-implant tissues subjected to loading. With the finite element analysis and the Von Mises method, it was possible to evaluate this distribution of forces both at 0 degrees (occlusal force) and at 30 degrees; the applied force was 800 N. The obtained results on this new type of connection and on all the implant components are satisfactory; the distribution of forces appears optimal even on the peri-implant tissues. Surely, studies like this help to obtain ever more performing devices, improving both the clinic and the predictability of rehabilitations.
TL;DR: In this article, the free vibration behavior of functionally graded (FG) rotating disk under thermal and centrifugal load, up to the limit elastic state of stress, was investigated. And the solution algorithm was executed by utilizing MATLAB® computational simulation software.
TL;DR: In this article, a combined experimental and computational method was developed to characterize the yield stress surface and the conjugate plastic strain-rate potential of the AA7075-O extruded tube under biaxial tension and biaaxial tension-compression stress states based on the plastic work equivalency assumption.
TL;DR: In this paper, a dynamic model of bubble expansion for predicting the geometry of the entrapped bubble by considering the elasto-vicsco-plastic rheology properties of the yield stress fluid and the resistance caused by the ambient yielded region was reported.
TL;DR: In this bone, both the maximum von Mises equivalent stress values and the Von Mises strain are similar or inferior to those reported in different studies by finite element for other models of dental implants under immediate loading.
Abstract: This study investigated the effect of three different parameters of a dental implant on stress and strain values in the peri-implant bone by finite element analysis. In this work, the effect of diameter, length and elastic modulus on the biomechanical behavior of a new dental implant was simulated using the finite element method. A three-dimensional model of a mandible segment corresponding to the premolar region and twelve dental implant models were obtained. Loads in three directions were distributed on the surface of the coronal area of the dental implants. The dental implant models were obtained in the FreeCAD 0.16 software and the simulations were made using the Abaqus/CAE software. In all cases, higher stress concentrations were obtained in the peri-implant cortical bone between 40.6 and 62.8 MPa, while the highest levels of strain were observed in the peri-implant trabecular bone between 0.002544 and 0.003873. In general, the highest von Mises equivalent stress values were observed in the peri-implant cortical bone. However, in this bone, both the maximum von Mises equivalent stress values and the von Mises strain are similar or inferior to those reported in different studies by finite element for other models of dental implants under immediate loading. Maximum von Mises strain values were observed in peri-implant trabecular bone. However, in this bone strains levels were obtained that maintain bone density or increase it. The effect of the three simulated variables (implant diameter, length, and elastic modulus) have a statistically significant influence on the von Mises equivalent stress and in von Mises strain values.
TL;DR: In this paper, the authors define material functions at yielding as the components of the static and dynamic yield stress tensors in viscometric, in uniaxial extension, in biaxially extension, and in planar extension conditions.
Abstract: In the present work, we define material functions at yielding in a perspective where elasticity and thixotropy can play an important role. These complex materials need to be characterized with a broader approach than the simple single value of the shear yield stress in a viscometric condition. Special emphasis is given to the distinction between static and dynamic yield stresses along with the distinction of viscometric and extensional yielding. The definition of static properties has no parallel with the usual material functions in nonyielding systems, like polymeric liquids, for example, where the words viscometric and extensional have a clear kinematic representation. Instead, static properties have to be measured by means of a stress state, since different stress states can be achieved where no motion takes place. We introduce the definition of material functions at yielding by specifying the yield stress tensor, an entity recently introduced by Thompson et al. [J. Nonnewton. Fluid Mech. 261, 211–219 (2018)], relative to a particular state. In this regard, we define the material functions at yielding as the components of the static and dynamic yield stress tensors in viscometric, in uniaxial extension, in biaxial extension, and in planar extension conditions.
TL;DR: In this paper, the propagation of stress waves in an impulsive load-excited fluid-filled cylindrical structure containing an internally clamped shell is investigated, where the external and internal cylinders are made of functionally graded and homogeneous isotropic materials, respectively.
Abstract: The propagation of stress waves in an impulsive load-excited fluid-filled cylindrical structure containing an internally clamped shell is investigated. The external and internal cylinders are made of functionally graded and homogeneous isotropic materials, respectively. The space between the cylindrical shells is filled with a non-viscous and compressible fluid. The equations of motion for solid media are based on the three-dimensional theory of elasticity. According to the problem definition, for establishing the relationship between the displacement and stress fields, the governing equations are extracted in the form of plane-strain. A laminate model is employed to attain the dynamic equations of the functionally graded cylinder. Next, a transfer matrix is established by considering the continuity conditions of the stress and displacement at the interfaces of the layers. Then, the Laplace transform is utilized to transfer wave equations from the time domain to the Laplace domain. Eventually, a numerical inverse Laplace transform known as the Durbin method is employed to retrieve the solutions obtained into the time domain. An excellent agreement is observed in comparing between results of the present analytical method and previous models. Next, the effects of geometrical and physical properties of the inner shell on the transient response of the functionally graded cylinder are investigated. Also, the von Mises stress as the most effective parameter in the structural design is studied. The results show that the inner shell made of a material with a lower elasticity modulus leads to a reduction in the amount of von Mises stress in the external cylinder. As well as, an inner shell with a greater volume has a more positive effect on the transient response of the functionally graded cylinder.