Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Yield function"”.
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A yield function to simulate earing in the deep drawing of aluminium
… texture models or phenomenological yield surface models. Crystallographic models have the advantage over phenomenological ones in that they are able to describe both initial and evolving anisotropy. However, they are very demanding in terms of computational power and are reported to …
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Failure of laterally crushed aluminum tubes under combined bending and tension
… models: the first is based on the von Mises yield function, the second on the non-quadratic isotropic Hosford yield function and the third on the anisotropic Yld04-3D yield function. The models were calibrated to the same stress-strain response and to data from a set of radial biaxial …
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Numerical investigation of theories of strain-gradient plasticity
… necessarily global in terms of the dissipation function. This relation cannot be inverted in closed form to obtain a relation in terms of a global yield function. Approximations to the yield function are proposed using a maximisation relation, and these predictions of yield are compared with …
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Predicting Stress Development in Gray Iron Foundry Castings
… behavior in tension and compression with a new yield function. A user-written element is also provided to apply force-displacement boundary conditions to the surface of the casting, eliminating the mold's finite element mesh from the problem. This new method for stress allows for the correct …
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Experimental investigation and constitutive modeling of marine clay
… having twelve parameters, consists of a failure function, plastic potential function (non-associated flow rule), yield function and hardening law. To describe the degree of cross-anisotropy at failure, a new four-parameter failure criterion is developed. The plastic potential function, having two …
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Negative skin friction on single piles in clay subjected to direct and indirect loading
… elastic perfectly plastic material with a yield function defined by the Mohr-Coulomb equation. The results of the numerical model compared well with the field data. A parametric study is presented to show the influence of various parameters on the location of neutral plane. It has been …
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Formulation, analysis and solution algorithms for a model of gradient plasticity within a discontinuous Galerkin framework
… plasticity in which the classical von Mises yield function is augmented by a term involving the Laplacian of the equivalent plastic strain is presented. The theory is developed within the framework of non-smooth convex analysis by exploiting the equivalence between the primal and dual …
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Hybrid experimental-numerical determination of the loading path to fracture in TRIP780 sheets subjected to multi-axial loading
… steel. It is found that an anisotropic quadratic yield function along with a non-associated flow rule can accurately describe the inelastic behavior of the TRIP material.
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Development of rate-dependent thermoplastic constitutive models for numerical analysis of ceramics at high-temperature
… and implements a shape evolution of the BP yield function, calibrated to simulate the forming of green bodies and their pre-sintering phase. Three algorithms are developed for the integration of constitutive equations when pathological yield functions are involved. The algorithms are coded …
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Experimental determination of the yield locus of anisotropic metal sheets using digital image correlation
The focus of this research was to determine the yielding and work hardening behaviour of two anisotropic steel sheets (DP600 and HSLA). Uniaxial tension and compression tests were performed in the rolling and transverse directions and at 45 degrees to the rolling direction for each sheet. …
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Long-term variation in cosmic-ray modulation
… to the addition of the third neutron monitor yield function. Despit that, these authors argue that these new calculated modulation potential remain consistent with the old values within the uncertainties. Herbst et al. (2010) have shown that the calculation of modulatio potentials do not only …
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A model for the time dependent behaviour of rock joints
… which uses a homogeneous, hyperbolic yield function is adopted. The viscoplastic relationship can be used for both time-dependent (creep) or quasi-static (elasto-plastic) problems. Time-dependent behaviour requires a time integration scheme and therefore a generalised explicit/implicit …
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Finite deformation of particulate geomaterials: frictional and anisotropic Critical State elasto-plasticity
… inelastic behaviour within the conventional yield surface and a Lode angle dependency on the anisotropic yield function which maintains convexity of both the surface and uniqueness of the Critical State cone. A calibration procedure is described and the integration and linearisation of the …
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A small strain, large rotation theory and finite element formulation of thin curved beams
… nonlinearity, which is based an the von-Mises yield function and the Prandtl-Reuss flow rule and in which isotropic hardening is assumed, has been included in the formulation. A family of three-diinensional beam elements, that can accurately accommodate the theory, has been developed by the …
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Dislocations and Green's functions in prestressed solids
… dissertation is divided into two Parts: Green's function and problems of the inclusions and dislocations are addressed in the first Part, while implementation of elastoplastic constitutive laws are treated in the second. These subjects can be seen as different approaches to the investigation of …
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Experimental investigation and constitutive modeling of the large deformation behavior of anisotropic steel sheets undergoing strain-induced phase transformation
… which describes the martensite content as a function of plastic strain, the stress triaxiality, and the Lode angle parameter. Furthermore, a phenomenological plasticity model is developed comprising an anisotropic yield function, an isotropic hardening law, and a nonlinear kinematic hardening …
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Anisotropic ductile fracture of metal sheets : experimental investigation and constitutive modeling
… of a linear-transformation- based orthotropic yield function with pressure dependence, as well as a combined isotropic/kinematic hardening law, and is able to capture most features of the anisotropic plastic behavior under various multi-axial stress states with good accuracy and computational …
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Constitutive equations for granular materials : application to dry sand and powder metal
… employs a pressure-sensitive, Mohr-Coulomb type yield condition, and a new physically based non-associated flow rule. For the consolidation mechanism the model employs a smooth yield function which has a quarter-elliptical shape in the mean-normal pressure and the equivalent shear stress plane, …
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Application of numerical limit analyses for undrained stability problems in clay
… by standard finite element interpolation functions. The thesis includes three substantial modifications of the pre-existing software: l) inclusion of structural beam and joint elements, that enable the program to model failure in combined bending, shear and axial loading; 2) implementation …