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.
Results
Showing 1 to 12 of 12 for “"Plasticity Models"”.
-
Continuity in Rigid Viscoplastic Flow
Classical plasticity models evolve state variables in a spatially independent manner through (local) ordinary differential equations, such as in the update of the rotation field in crystal plasticity. This approach emanates from how the deformation has been described, e.g. the multiplicative …
-
Numerical Modeling Issues in Finite Element Simulation of Plasticity Induced Crack Closure With an Emphasis on Material Model Effects
Plasticity induced crack closure (PICC) has a potentially strong effect on the growth rate of fatigue cracks in metal structures. As a crack grows through previously yielded material, the permanent deformation in the crack wake Shields the crack tip from the full impact of the remote load. This …
-
Numerical analysis of plastic deformation in metal-ceramic nanolayers during cyclic indentation
… study, both rate-independent and rate-dependent plasticity models are considered. It is found that, in the multilayered material plastic deformation in the Al layers continues to occur upon unloading and subsequent loading /unloading operations. The cyclic plasticity results in an open …
-
Simulating Blast Effects In Steel Skeletal Structures
… component is derived that uses bounding surface plasticity models, defined in stress-resultant space, to represent the effects of the blast by way of a plastic reduction matrix. Each bounding surface is created by generating numerical failure data for a given component and explosive scenario …
-
Seismic modeling, analysis and design of structural concrete pile-deck connections
… envelopes needed for implementation in lumped plasticity models have already been developed. A more refined computational approach then includes full-length piles, and thus soil-structure interaction and in-ground nonlinear effects are accounted for. Rotational ductility is identified as a …
-
Nanoindentation characterization of clay minerals and clay-based hybrid bio-geomaterials
… test based on continuum mechanics and gradient plasticity models, therefore, give satisfactory result. On the other hand, chemical, morphological, microstructural and structural characterization of a hybrid clay-lime-starch bio nanocomposite material revealed highly heterogeneous, amorphous and …
-
Progressive failure of slopes in lined waste impoundments
… was a principal focus of this study. Two new plasticity models for interface behavior, a displacement-softening model and a work-softening model, were developed to simulate strength reduction along liner interfaces. The work-softening model performs better than the displacement-softening model …
-
Dry sliding wear of metals: From subsurface microstructure to tribological behavior
… were compared with predictions from several plasticity models, such as Sachs model, rate-dependent Taylor model with full or relaxed constraints, and an intermediate Sachs-Taylor model to gain new understanding on single-grain plasticity. Microstructural heterogeneity was observed in the …
-
Quasi-Static and Creep Behavior of Enhanced SIC/SIC Ceramic Matrix Composites
… were compared with the time and strain hardening models. Microscopic observations on the fractured surfaces revealed the pseudo-ductile behavior of the material at high temperatures. A quasi-static test was conducted at 1200 °C to determine the unloading response of the material. The stress-strain …
-
Numerical Modeling of UHPC using a Concrete Damage Plasticity Model
Ultra-High Performance Concrete (UHPC) is a type of concrete that is known for its high compressive strength, elastic-plastic or strain hardening tensile behavior, and enhanced material ductility and toughness. These properties are achieved through the use of a low water-to-binder ratio, optimized …
-
Formulation and Implementation of a Constitutive Model for Soft Rock
… chalk. Chalk behavior is characterized by elastoplasticity, including pore collapse, shear failure, and tensile failure mechanisms; rate-dependence; and pore fluid dependence. The research described in this dissertation was performed with the objectives to formulate a constitutive model which …
-
The rheological complexity of waxy crude oils : yielding, thixotropy and shear heterogeneities
… and capture with existing constitutive models. The contribution of this thesis is therefore to develop a detailed understanding of three of these particular phenomena, through the development and use of several new experimental and theoretical tools. A better understanding of waxy crude …