Showing papers on "von Mises yield criterion published in 2005"
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01 Jan 2005
TL;DR: In this article, the integration of von Mises Plasticity into Finite Element Code is discussed. But the integration is restricted to the Duva and Crow Model and not to the TMF model.
Abstract: 1. Microplasticity 2. Continuum Plasticity 3. Kinematics of Large Deformations and Continuum Mechanics 4. The Finite Element Method for Static and Dynamic Plasticity 5. Implicit and Explicit Integration of von Mises Plasticity 6. Implementation of Plasticity Models in to Finite Element Code 7. Superplasticity 8. Porous Plasticity: the Duva and Crow Model 9. Creep in an Aero-Engine Combustor Material 10. Cyclic Plasticity, Creep and TMF A. Elements of Tensor Algebra B. Fortran Coding available via the OUP web site
399 citations
TL;DR: An ellipse criterion is proposed as a new failure criterion to unify the four classical criteria above and apply it to exemplarily describe the tensile fracture behavior of BMGs as well as a variety of other materials.
Abstract: We find that the classical failure criteria, i.e., maximum normal stress criterion, Tresca criterion, Mohr-Coulomb criterion, and von Mises criterion, cannot satisfactorily explain the tensile fracture behavior of the bulk metallic glass (BMG) materials. For a better description, we propose an ellipse criterion as a new failure criterion to unify the four classical criteria above and apply it to exemplarily describe the tensile fracture behavior of BMGs as well as a variety of other materials. It is suggested that each of the classical failure criteria can be unified by the present ellipse criterion depending on the difference of the ratio alpha = tau(0)/sigma(0).
228 citations
TL;DR: In this paper, the Von Mises equivalent strain to crack formation, stress triaxiality, and stress and strain ratios at critical locations, were obtained for ductile crack formation in tensile tests.
182 citations
TL;DR: In this article, the authors defined a damage stress as the stress corresponding to, on the S-N curve, the instantaneous residual life, and proposed a damage indicator which is connected cycle by cycle to the Wohler curve and the experimental results are in agreement with model expectations.
110 citations
TL;DR: In this paper, a finite element model of the residual stresses and strains that are formed after an elastoplastic hemispherical contact is unloaded is presented, where the material is modeled as elastic perfectly plastic and follows the von Mises yield criterion.
Abstract: This work presents a finite element model (FEM) of the residual stresses and strains that are formed after an elastoplastic hemispherical contact is unloaded. The material is modeled as elastic perfectly plastic and follows the von Mises yield criterion. The FEM produces contours for the normalized axial and radial displacements as functions of the removed interference depth and location on the surface of the hemisphere. Contour plots of the von Mises stress and other stress components are also presented to show the formation of the residual stress distribution with increasing plastic deformation. This work shows that high residual von Mises stresses appear in the material pileup near the edge of the contact area after complete unloading. Values are defined for the minimum normalized interference, that when removed, results in plastic residual stresses. This work also defines an interference at which the maximum residual stress transitions from a location below the contact region and along the axis of symmetry to one near to the surface at the edge of the contact radius (within the pileup).
106 citations
TL;DR: In this article, the variation of springback in high strength steels due to material anisotropy is investigated and results from both numerical and experimental investigations are conducted and results of both are analyzed and discussed.
103 citations
TL;DR: In this article, an anisotropic yield criterion with a general representation was proposed, derived from the use of the invariants of the stress tensor, similar in constructing an isotropic yield criterion, but which contains a three-yield-system hypothesis specifying the state of anisotropy.
87 citations
TL;DR: In this paper, the steady-state thermal effect is considered and a thermo-elastic-plastic contact model is developed, which is applicable for rolling and/or sliding contact problem, as far as small equivalent plastic strain hypothesis is respected.
Abstract: The stress field within machine components is an important indicator for contact failures. Since both thermal stresses due to frictional heating and plasticity are significant in engineering application, it is critical to predict the total stress field. In this work, the steady-state thermal effect is considered and a thermo-elastic-plastic contact model is developed. The model is applicable for rolling and/or sliding contact problem, as far as small equivalent plastic strain hypothesis is respected. Influence coefficients for surface normal displacement, temperature, and strain and stress tensors are used with the discrete convolution and fast Fourier transform algorithm. The single-loop conjugate gradient iteration scheme is also applied to achieve fast convergence speed. Simulations are presented for several academic examples ranging from elastic to thermo-elastic-plastic. The thermo-elastic-plastic analyses show that the heat factor in a contact situation has significant effect not only on the critical Hertzian pressure and on the pressure distribution, but also on the magnitude and depth of the maximum von Mises stress during loading and the residual ones found after unloading.
85 citations
TL;DR: It was found that maximum von Mises equivalent stress in bone decreased as cortical bone thickness increased and increased as Young's modulus of cortical bone increased.
Abstract: Using finite element method (FEM), this study sought to investigate how the thickness and Young's modulus of cortical bone influenced stress distribution in bone surrounding a dental implant. The finite element implant-bone model consisted of a titanium abutment, a titanium fixture, a gold alloy retaining screw, cancellous bone, and cortical bone. The results showed that von Mises equivalent stress was at its maximum in the cortical bone surrounding dental implant. Upon investigation, it was found that maximum von Mises equivalent stress in bone decreased as cortical bone thickness increased. On the other hand, maximum von Mises equivalent stress in bone increased as Young's modulus of cortical bone increased. In conclusion, it was confirmed that von Mises equivalent stress was sensitive to the thickness and Young's modulus of cortical bone.
72 citations
TL;DR: The purpose of this study was to examine the stress distribution in distal cantilevered fixed partial dentures (FPDs) that are designed with different cantilever morphology and made from different restorative materials and revealed that Von Mises stress values with maximum stress concentrations were observed on connectors of distal Cantilevers.
Abstract: summary The purpose of this study was to examine the stress distribution in distal cantilevered fixed partial dentures (FPDs) that are designed with different cantilever morphology and made from different restorative materials. The finite element (FE) method was used to create models of two restoration types; metal-ceramic and an all-ceramic FPDs. Both models were designed with distal cantilevers involving the first and second premolars as abutments and cantilever extension involving at the premolar or molar. The width of connector between the cantilever and the primary abutment restoration was 2·25 mm. The load applied during the FE analysis was positioned at the cusp tips of all teeth. The FE analysis of the models revealed that Von Mises stress values with maximum stress concentrations were observed on connectors of distal cantilevers. Stress concentration sites were also observed at the distal cervical area of the second premolar tooth. Models with premolar cantilever extensions restored with all-ceramic induced lower Von Mises stress values than metal-ceramic restorations, however models with molar cantilever extensions restored with all-ceramic restorations induced higher Von Misses stress values than metal-ceramic restorations. If the distal cantilever length and restorative material is appropriately chosen, the failure frequency may be reduced. All ceramic can be used as restorative material, when the cantilevers length is not more than the mesiodistal dimension of a premolar tooth and metal-ceramic restorations can be used in longer situations.
71 citations
TL;DR: In this paper, the authors employed this equilibrium-equivalent structural stress method for a competition organized by the SAE Fatigue Design & Evaluation (FD&E) Committee to predict the fatigue life of a rectangular hollow section joint.
TL;DR: The finite element method discretized static shakedown analysis of steel constructions leads to large, sparse convex optimization problems, for which the most appropriate techniques are Interior Point Methods.
Abstract: The finite element method discretized static shakedown analysis of steel constructions leads to large, sparse convex optimization problems. Under the von Mises yield criterion, they lead to second-order cone programming problems, for which the most appropriate techniques are Interior Point Methods. Various approaches exploiting the specific characteristics of the shakedown problems are presented and discussed.
TL;DR: In this article, a general autofrettage model that incorporates the material strain-hardening relationship and the Bauschinger effect, based upon the actual tensile-compressive stress-strain curve of a material is proposed.
Abstract: The basic autofrettage theory assumes elastic-perfectly plastic behaviour. Because of the Bauschinger effect and strain-hardening, most materials do not display elastic-perfectly plastic properties and consequently various autofrettage models are based on different simplified material strain-hardening models, which assume linear strain-hardening or power strain-hardening or a combination of these strain-hardening models. This approach gives a more accurate prediction than the elastic-perfectly plastic model and is suitable for different strain-hardening materials. In this paper, a general autofrettage model that incorporates the material strain-hardening relationship and the Bauschinger effect, based upon the actual tensile-compressive stress-strain curve of a material is proposed. The model incorporates the von Mises yield criterion, an incompressible material, and the plane strain condition. Analytic expressions for the residual stress distribution have been derived.Experimental results show that the pr...
TL;DR: In this article, the effect of geometrical parameters, such as gage height and root radius, on the stress and strain distribution and concentration was investigated numerically using three-dimensional elastoplastic finite element simulations.
Abstract: The shear compression specimen (SCS), which is used for large strain testing, is thoroughly investigated numerically using three-dimensional elastoplastic finite element simulations. In this first part of the study we address quasi-static loading. A bi-linear material model is assumed. We investigate the effect of geometrical parameters, such as gage height and root radius, on the stress and strain distribution and concentration. The analyses show that the stresses and strains are reasonably uniform on a typical gage mid-section, and their average values reflect accurately the prescribed material model. We derive accurate correlations between the averaged von Mises stress and strain and the applied experimental load and displacement. These relations depend on the specimen geometry and the material properties. Numerical results are compared to experimental data, and an excellent agreement is observed. This study confirms the potential of the SCS for large strain testing of material.
TL;DR: In this paper, a numerical three-dimensional contact model is presented to investigate the contact behavior of rough, multilayered elastic-perfectly plastic solid surfaces based on a variational principle in which the contact pressure distributions are those which minimize the total complementary potential energy.
15 Nov 2005
TL;DR: In this paper, the effect of temperature on the performance of fiber metal laminates has been characterised via experimental testing and numerical modelling, where the authors used Park's method to solve the dynamic system of equations, taking the heat capacity, inertia forces and damping into account.
Abstract: Fibre metal laminates, such as Arall or Glare, can offer improved properties compared to monolithic materials Glare for example shows improved fatigue, residual strength, burn-through, impact and corrosion properties with respect to aluminium 2024, together with a considerable weight reduction and competitive costs A large research program has proven the technological readiness of Glare and the fibre metal laminate has seen its application today in the primary structure of the Airbus A380 super jumbo However, the effect of temperature on the performance of the fibre metal laminates has not been fully characterised Differences in thermal expansion coefficients cause residual stresses after curing of the laminate In service the temperature of the aircraft skin can vary between -55 up to 70 C due to solar radiation and convection, which will affect the thermal and mechanical properties of Glare A detailed understanding of the behaviour of these laminates is necessary for further improvement of their performance and durability With the increase in complexity of structures and material systems, the need for powerful design tools becomes evident In this thesis, the thermo-mechanical behaviour of fibre metal laminates has been characterised via experimental testing and numerical modelling Experimental tests have been performed to determine the temperature-dependent thermal and mechanical behaviour of unidirectional (UD) glass-fibre epoxy Calculations based on these test results at room temperature and 80 C for the tension and shear stiffness of three different composite laminate lay-ups showed a good agreement with experimental test results The UD glass-fibre epoxy data is used as input for the finite element model, together with aluminium 2024-T3 data from the literature Glare laminates with a special lay-up have been experimentally tested to determine the effect of temperature and mechanical loadings on the laminate characteristics The test results show that the off-axis and temperature effect can give a reduction of 24% in ultimate strength at room temperature due to off-axis loading and a further reduction of 17% at 80 C temperature For standard Glare from the literature, where tests at elevated temperature have only been performed in fibre direction, the strength and stiffness reductions are at most 12% compared to room temperature Numerical simulation is a very powerful tool to investigate the behaviour of materials and structures Therefore, a thermo-mechanical finite element model, based on a solid-like shell element and including thermal expansion and heat transfer, has been developed to capture the behaviour of Glare in a fully three-dimensional state The through-the-thickness temperature and stress distributions can thereby be determined, which allows for a straight-forward implementation of damage and plasticity models Moreover, the solid-like shell element is ideal for thin-walled (aerospace) structures since it can have high aspect ratios without showing Poisson thickness locking, which occurs in standard continuum elements, and can have multiple layers in one element To account for physical nonlinearities, a strain hardening model for the aluminium 2024-T3 and an orthotropic damage model for the UD glass-fibre epoxy layers in Glare are used The strain hardening behaviour of aluminium has been modelled with a yield function based on an isotropic Von Mises plasticity formulation An exponentially saturating hardening law has been assumed, which gives a good agreement with the experimental aluminium 2024-T3 stress-strain curve A return-mapping algorithm is used to project the stress back onto the yield surface when the stress state violates the loading condition The concept of continuum damage mechanics is used, with a separate damage parameter for fibre and matrix, to describe the appearance of microcracks that lead to ultimate failure The equivalent strain measure is obtained by rewriting the yield function of the orthotropic Hoffman plasticity model into a strain-based format The damage parameters are directly implemented into the stiffness matrix to avoid undesirable coupling terms in the damage matrix The simulations of the shear and tensile test in transverse direction show a good fit with the experimental curves for the UD glass-fibre epoxy The transient behaviour is captured by taking the heat capacity, inertia forces and damping into account Park's method is used to solve the dynamic system of equations The good performance of the thermomechanical solid-like shell element and the transient solver have been demonstrated for a single element under thermo-mechanical loadings and the snap-through of a cylindrical panel subjected to a concentrated load Via a number of benchmark tests for practical applications the obtained numerical model is compared with the experimental test results Bluntnotch test simulations have been performed on Glare3-3/2-04 and on a special Glare laminate (tested at 0, 45, 675, and 90 off-axis angle), which show a good agreement with experimental results Simulations of off-axis tensile tests on a 0/90 composite, tensile tests on standard Glare laminates, and off-axis tensile tests on special Glare laminates with additional fibre layers in -45 and 45 direction, also showed a good agreement with experimental results The thermo-mechanical solid-like shell element and the experimentally obtained material data, presented in this thesis, together create a powerful simulation tool for the effective and accurate characterisation of fibre metal laminates under thermo-mechanical loadings
TL;DR: In this article, the fiber pullout test has been used as a surrogate for estimating fracture toughness of fiber-matrix systems and a mixed "cohesive" and "Coulomb-friction" model was proposed to simulate the entire pullout process.
Abstract: The fiber pullout test has long served as surrogate for estimating fracture toughness of fiber–matrix systems. In this paper, the quasi-static analysis of elastoplastic fiber pullout process is simulated by the finite element method based on an updated Lagrangian formulation. To approximate the non-linear behavior of the fiber–matrix interface, we propose a mixed ‘cohesive’ and ‘Coulomb-friction’ model. The use of such a model enables us to simulate the entire pullout process. A combination of von Mises yield criterion and associated flow rule is utilized as the constitutive model to describe the plasticity in the initially annealed copper-fiber. Through comparison with the experimental results from straight-fiber pullout, key parameters for describing the interface model are determined and the model is validated. The model is then applied to simulate the pullout of the ‘nail-head’ shaped fiber family. Simulation results are used to design an optimal shape of the head to maximize the pullout work.
TL;DR: In this article, a finite element-based analysis is presented to determine if thermal induced stresses in inter-wafer Cu via structures in 3D ICs using BCB-bonded wafers is a potential reliability problem.
TL;DR: In this article, the effect of double notched bar specimens over a range of nominal stress states was investigated, and the constitutive equations for uniaxial creep deformation in nickel alloy C263 were implemented into finite element code.
TL;DR: In this article, a kinematic hardening model applicable to finite strains is presented, which is based on the residual stresses that evolve due to different obstacles that are present in a polycrystalline material, such as grain boundaries, cross slips, etc.
TL;DR: In this paper, two approaches, namely, two-parameter fracture mechanics and micro-mechanical models are considered to investigate the feasibility of transferability of fracture parameters, and it is shown that if the triaxial conditions match for any two arbitrary geometries, it is feasible to transfer the fracture parameters.
TL;DR: In this paper, a yield criterion based on a physical hypothesis was proposed to fulfill the experimental observations, which can well predict the yielding behavior arising from the yielding mechanism of the multiple-factor dependence.
TL;DR: The orbital-free density functional theory local quasi-continuum\linebreak (OFDFT-LQC) method is introduced: a first-principles-based multiscale material model that embeds OFDFT unit cells at the subgrid level of a finite element computation.
Abstract: We introduce the orbital-free density functional theory local quasi-continuum\linebreak (OFDFT-LQC) method: a first-principles-based multiscale material model that embeds OFDFT unit cells at the subgrid level of a finite element computation. Although this method cannot address intermediate length scales such as grain boundary evolution or microtexture, it is well suited to study material phenomena such as continuum level prediction of dislocation nucleation and the effects of varying alloy composition. The model is illustrated with the simulation of dislocation nucleation during indentation into the $(111)$ and $(\overline{1}10)$ surfaces of aluminum and compared against results obtained using an embedded atom method interatomic potential. None of the traditional dislocation nucleation criteria (Hertzian principal shear stress, actual principal shear stress, von Mises strain, or resolved shear stress) correlates with a previously proposed local elastic stability criterion, $\Lambda$. Discrepancies in dislocation nucleation predictions between OFDFT-LQC and other simulations highlight the need for accurate, atomistic constitutive models and the use of realistically sized indenters in the simulations.
TL;DR: In this article, the stress distribution in a nonhomogeneous anisotropic cylindrical body is investigated using equilibrium equations, Hooke's law and strain-displacement relations.
TL;DR: In this paper, failure initiation under compressive loading in non-crimpfabric composites containing bundles with out-of-plane orientation imperfections was analyzed using FEM in plane stress and linear elastic formulation.
Abstract: Failure initiation under compressive loading in non-crimpfabric composites containing bundles with out-of-plane orientation imperfections was analyzed using FEM in plane stress and linear elastic formulation. The bundle orientation imperfection in a composite unit was described by a sine function. Failure initiation strain was determined comparing failure functions corresponding to two alternative failure mechanisms: (a) plastic microbuckling in bundle due to mixed compressive and shear load; (b) plastic matrix yielding according to von Mises criterion. Parameters for compressive failure initiation analysis were bundle misalignment angle, fiber volume fraction inside the bundle and bundle volume fraction inside the composite unit. The support effect of the neighbouring material was analyzed varying boundary conditions and solving cases with particular configuration of surrounding material. Model prepreg tape GF/EP composite with different introduced levels of out-of-plane waviness of layers was used to validate the conclusions from parametric analysis.
TL;DR: In this paper, a plane-strain 2D finite-element model is used to investigate the mechanical role of a ductile layer in defining the transition from localized to distributed fracturing in a brittle layer.
Abstract: Localized or distributed deformations in continental lithosphere are supposed to be triggered by rheological contrasts, and particularly by brittle-ductile coupling. A plane-strain 2D finite-element model is used to investigate the mechanical role of a ductile layer in defining the transition from localized to distributed fracturing in a brittle layer. The coupling is performed through the shortening of a Von Mises elasto-visco-plastic layer rimed by two ductile layers. By increasing the viscosity of the ductile layers by only one order of magnitude, the fracturing mode in the brittle layer evolves from localized (few faults) to distributed (numerous faults), defining a viscosity-dependent fracturing mode. This brittle-ductile coupling can be explained by the viscous resistance of the ductile layer to fault motion, which limits the maximum displacement rate along any fault connected to the ductile interface. An increase of the viscosity will thus make necessary new faults nucleation to accommodate the boundary shortening rate.
TL;DR: In this article, a finite-element analysis and experiments were conducted to analyze the behavior of crack propagation after ductile fracture in bulk metal forming processes, where the authors focused on the effect of various fracture criteria on crack initiation and propagation.
TL;DR: In this paper, the theoretical link between the micromechanical and macroscopic behavior of granular materials and the relationship between the two and three dimensional behaviour of the model is discussed.
Abstract: This paper reviews fundamental behaviour of a strain space multiple mechanism model for granular materials. Although this model has previously been implemented in a finite element program and used in the analysis of numerous practical problems for evaluating seismic performance of geotechnical works, most of the application was limited to the two dimensional boundary value problems. This paper reviews the theoretical link between the micromechanical and macroscopic behaviour of granular materials and discusses the relationship between the two and three dimensional behaviour of the model. The strain space multiple mechanism model characterizes a twofold structure of an assemblage of particles: the first is a multitude of virtual two dimensional mechanisms, the second a multitude of virtual simple shear mechanisms of one dimensional nature. Due to the twofold structure, a yield criterion specified in the micromechanical level does not reproduce the same yield criterion at the macroscopic level. There is an effect of the intermediate principal stress. Based on this finding, the paper proposes a methodology to introduce various macroscopic yield criteria, including Tresca, von Mises, extended Tresca, Drucker–Prager, Mohr–Coulomb, and extended Mohr–Coulomb criteria within the framework of the strain space multiple mechanism model. Performance of this model incorporating various yield criteria is demonstrated for monotonic and cyclic loading, under drained and undrained conditions. Copyright © 2005 John Wiley & Sons, Ltd.
TL;DR: In this paper, a single-edge fatigue crack propagated in transgranular manner through Pb-rich phases and Sn-rich phase near the solder-copper interface, which resulted in interfacial debonding near the crack tip.
TL;DR: In this paper, a combined smoothing and successive approximation (CSSA) method is proposed for the sequential limit analysis of plane-strain problems of the von Mises model with non-linear isotropic hardening.
Abstract: The paper presents sequential limit analysis of plane-strain problems of the von Mises model with non-linear isotropic hardening by using a general algorithm. The general algorithm is a combined smoothing and successive approximation (CSSA) method. In the paper, emphasis is placed on its convergence analysis and validation applied to sequential limit analysis involving materials with isotropic hardening. By sequential limit analysis, the paper treats deforming problems as a sequence of limit analysis problems stated in the upper bound formulation. Especially, the CSSA algorithm was proved to be unconditionally convergent by utilizing the Cauchy–Schwarz inequality. Finally, rigorous validation was conducted by numerical and analytical studies of a thick-walled cylinder under pressure. It is found that the computed limit loads are rigorous upper bounds and agree very well with the analytical solutions. Copyright © 2005 John Wiley & Sons, Ltd.