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 20 of 35 for “"micromechanical models"”.
-
Micromechanical models of delamination in aluminum-lithium alloys
… different theories of hardening. The microscale models reveal soft/stiff grain boundaries develop elevated mean stress and plastic strain as a consequence of the mechanics of the interface. These elevated stresses and strain drive plastic void growth. The results indicate plastic void growth …
-
Simplified micromechanical models for analysis of interface debonding in a fibrous composite
… objective of this study is to develop simplified micromechanical models to analyze the interface debonding between fiber and the matrix materials. Both analytical and simplified finite element models are used to predict the effective transverse elastic modules of fibrous composites with a partial …
-
Activation of conductive pathways via deformation-induced instabilities
… pattern transformation. Finite element-based micromechanical models are employed to investigate the effects of the contact nub geometries, conductive pathway patterns and elastic properties of the coating and substrate materials on the buckling responses of the structure. Finally, a flexible …
-
Micromechanics of strength-related phenomena in composite materials
Micromechanical models are presented which can be used to evaluate: stress concentrations in the vicinity of single and multiple fiber fractures in unidirectional composites under axial loading; the tensile strength of unidirectional composites; fiber coatings that can be used to maximize the …
-
Axial, flexural and torsional rigidities of two-dimensional braided fibre composite medical catheters
… values of Efl1, E m and Gm are required for the micromechanical model; the model is not sensitive to the remaining elastic constants (nuf12, nu f23, Gfl2, G23). Oversized braided (Kevlar 49 fibre and thermoset matrix) engineering model composite structures---or model catheters---have been used to …
-
Micromechanics of deformation in polymers modified by inorganic and rubber particles
… of plastic deformation in the matrix material. Micromechanical models are constructed for the both the isotropic and anisotropic polymer matrix modified by rubber and inorganic particles. For the case of the inorganic particle, the two limiting bonding cases examined are the incoherent and the …
-
Modeling the deformation and failure behavior of FCC and HCP nanocrystalline materials
… 100nm level. In this dissertation, constitutive models have been developed to investigate the deformation mechanisms of nc materials, with focus on modeling grain-boundary decohesion in nc materials. Two micromechanical models have been developed to capture the deformation in grain boundaries in …
-
Mechanics of large-strain deformation of particle-modified polymers
… and verify single-particle and multi-particle micromechanical models.
-
Hierarchical material models with microstructure for nonlinear analysis of progressive damage in laminated composite structures
… modeling approaches using hierarchical 3D micromechanical models for the analysis of progressive damage in laminated structures. Each approach is generally a synthesis of three components: a nonlinear material model for the matrix behavior; a micromodel for the unidirectional lamina; and a …
-
Mechanics and design of flexible composite fish armor
… macroscale prototypes and finite element based micromechanical models are employed to measure mechanical response to blunt and penetrating indentation loading. Deformation mechanisms of scale bending, scale rotation, tissue shear, and tissue constraint were found to govern the ability of the …
-
A Semi-analytical Model for Nonlinear Elliptical Inclusions with Spherical Eigenstrains
… has been essential in developing homogenized micromechanical models for metals and composites. However, as solid mechanics research increasingly focuses on soft materials such as biological tissues, a linear theory is no longer sufficient. Despite numerous potential applications ranging from …
-
Atomistic simulations of octacyclopentyl polyhedral oligomeric silsesquioxane polyethylene nanocomposites
… modulus increased with increasing POSS content. Micromechanical models were fit to the composite modulus which allowed effective mechanical particle sizes to be determined.
-
Magnetostrictive Particle Tagging of Epoxy and Epoxy Composites for Self Assessment of Damage
… in proportion to the size of the damage zone. Micromechanical models are developed to analyze the experimental results. Tagging of polymers and polymer composites using Terfenol-D is shown to yield materials with unique health monitoring capabilities. Their behavior is predictable and is highly …
-
Stress rupture of unidirectional polymer matrix composites in bending at elevated temperatures
… specimen has been established. Three different micromechanical models have been applied to analyze the time-to-failure versus strain behavior at two temperatures - one below and one above the glass transition. The first micromechanical model considers the nucleation of the microbuckles as the …
-
An anisotropic damage model for rock
… a general loading path. Experimental data and micromechanical models are reviewed to quantify the effect of microcracking on the material stiffness and the mechanisms of microcrack formation in brittle rocks under compression are discussed. The sliding crack concept is adopted as the …
-
Mechanics of deformation of carbon nanotube-polymer nanocomposites
… the composite, both micro- and macroscopically. Micromechanical models of representative volume elements (RVEs) of unit-cell and random multi-particle distributions are used to study such parameters and their performance and accuracy in doing is compared and discussed. The microstructural …
-
Modeling and simulation of creep rupture in high-temperature alloys
… of this dissertation is to develop more accurate micromechanical models of creep rupture that can be used to gain further insight into the failure of high temperature alloys. We consider such model systems as a stationary crack tip in the absence of voids, a single intergranular void growing under …
-
Micromechanical modeling of the toughening mechanisms in particle-modified semicrystalline polymers
… heterogeneous material systems via a series of micromechanical models. The case of polyamide-6 modified with spherical elastomeric particles was modeled. The finite element method was employed to conduct a parametric study on the deformation of these systems. It was found that the mechanical …
-
Large strain time-dependent behavior of elastomeric materials
… and important to its function, few models attempt to quantify these aspects of response. Based on a detailed experimental investigation a new constitutive model for the time-dependence of unfilled elastomers has been developed. The foundation of the model is that the mechanical …
-
Micro/nanoscale modeling of anisotropic mechanical properties of polymer/layered-silicate nanocomposites
… enhancements is explored. Two-dimensional models of various representative volume elements (RVEs) of the underlying structure of the polymer nano-clay composite are constructed. These models are characterized by clay particle volume fraction and micro/nano scale morphological features such …
Page 1 of 2