Examinando por Materia "loading"

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    Multiaxial cyclic plasticity in accordance with 1D hyperbolic models and Masing criteria
    (John Wiley and Sons Ltd, 2018-12-10) Restrepo, D.; Taborda, R.; Mecánica Aplicada
    Bounding surface plasticity models based on one-dimensional hardening functions are broadly accepted as a valid approach to represent the multiaxial cyclic behavior of undrained cohesive soils. However, under certain conditions, these models may exhibit deviations from the expected stress path. This makes them inadequate to meet traditional hysteretic rules. Current solutions to this problem impose thresholds to help adjust the stress path by introducing additional memory variables. This article presents a formulation that achieves the same goal without the need of such additional variables. The proposed formulation operates on a generic hardening function under multiaxial loading while preserving the simplicity inherited from pure deviatoric bounding surface models. In addition, the approach presented here allows the implementation of Masing-type rules, as well as the use of reduction factors to mitigate the overdamping effects of large hysteresis loops. The formulation is tested using well-known hyperbolic backbone functions under radial and nonradial multiaxial loading cycles, and it is shown to have good agreement with reference solutions. © 2018 John Wiley & Sons, Ltd.
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    Triaxial deformation behavior of bituminous mixes
    (ASCE-AMER SOC CIVIL ENGINEERS, 2010-02-01) Ossa, E. A.; Deshpande, V. S.; Cebon, D.; Ossa, E. A.; Deshpande, V. S.; Cebon, D.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    The triaxial compressive response of bituminous mixes with volume fractions of aggregate in the range 52 to 85% was investigated over a wide range stresses and strain rates. The types of loadings considered include triaxial monotonic constant stress and constant applied strain rate, as well as creep recovery, continuous cyclic, and stress pulse train loadings. The mixes with a "fully dense" aggregate skeleton were found to dilate under all loading conditions and the creep response of the mixes was dependent on both the deviatoric and hydrostatic stresses. By contrast, recovery was found to occur under zero applied deviatoric stresses with the recovery rate only dependent on the "recoverable strain" and independent of any superimposed hydrostatic stress. Continuous and pulse loading cyclic stress-controlled tests showed that the response of the mixes was governed by the mean applied deviatoric stress in the continuous cyclic tests while strain recovery was important in the pulse loading tests. A phenomenological constitutive model was proposed to fit the measured triaxial response of the bituminous mixes and shown to capture the measurements over all the triaxial stress states and loading time histories investigated here. Furthermore, the model was extended to capture the temperature dependence of the mixtures which is governed by the temperature dependence of the bitumen binder. © 2010 ASCE.