Global ETD Search

1	Modélisation dynamique de la thermo-viscoélasticité des matériaux bitumeux : Application aux essais FWD sur les structures des chaussées / Dynamic modelling of the thermo-viscoelasticity of bituminous materials : Application to FWD testing on pavement structures Tautou, Rémi 19 May 2016 (has links) Le diagnostic du parc routier est une étape indispensable préalable à l'entretien et la réparation des structures de chaussées. L'importance d'une plus grande finesse de l'analyse des résultats issus des méthodes de contrôle non destructif peut permettre de réaliser, à terme, des économies sur les coûts et énergie mis en jeu lors de la maintenance et la construction. Ces travaux de doctorat présentent un modèle thermo-visco-elastique permettant d'intégrer le comportement des matériaux bitumineux composant une chaussée par l'utilisation du module et de l'amortissement complexe issu des courbes maitresses. La résolution du problème dynamique est réalisée à l'aide d'une approche fréquentielle. Cette approche est appliquée en particulier à un essai FWD sur lequel des variations climatiques sont étudiées. Des essais in situ, réalisés sur deux sites instrumentés, permettent de valider le modèle. Les bons résultats obtenus suggèrent l'utilisation de ce modèle à travers une analyse multicritère sur les bassins de déflexion et les historiques pour le développement futur d'un modèle de retro calcul dynamique. / The diagnosis of the road fleet becomes a necessary step prior to themaintenance and the repair of pavement structures. The importance of a finer analysis of the results of the non-destructive testing methods can eventually achieve to cost and energy savings for the maintenance and construction. This phD thesis introduces a thermo-visco-elastic model for intersting the behavior ofbituminous pavement materials, using the complex modulus and damping from master curves. The resolution of the dynamic problem is performed thanks to a frequency approach. This approach is particularly applicable to a FWD test on which climatic variations are studied. In situ tests, carried out on two instrumented sites, are used to validate the model. The obtained of good results suggests the use of this model through a multi-criteria analysison deflection basins and of the records for the future development of a backcalculation dynamic model. Thermo-viscoélasticité FWD Méthode fréquentielle Thermo-viscoelasticity FWD Frequency Method 624.18
2	<b>An Integrated Physics-Based Multiscale Modeling Framework for Advancing Thermoset Composites Manufacturing Processes</b> Ryan Scott Enos (20449379) 19 December 2024 (has links) <p dir="ltr">The manufacturing of composite materials presents numerous opportunities due to their superior properties, including high strength-to-weight ratios and excellent fatigue resistance, which make them ideal for advanced engineering applications. However, realizing these advantages is challenging due to complexities in manufacturing processes, which can introduce defects, residual stress, and variability. This study aims to address these challenges through the development of integrated, physics-based processing models that are capable of predicting and mitigating manufacturing defects in advanced composites. The research focuses on the integration of these physics-based models with data-driven methods such as statistical analysis, uncertainty quantification, and optimization. A significant emphasis is placed on modeling the thermo-viscoelastic (TVE) behavior of curing composites, which is often simplified in processing simulations due to computational costs, by approximating to elastic responses according to the Cure Hardening Instantaneously Linear Elastic (CHILE) model. Results show that cure-dependent TVE process simulations implemented through Finite Element Analysis (FEA) can be efficiently integrated with optimization algorithms. 570 simulations completed in 109 min on a local desktop computer. Building on these advancements, this work further investigates Automated Fiber Placement (AFP) under the context of Integrated Computational Materials Engineering (ICME), and establishes the groundwork and serves as roadmap for AFP research at Purdue University with a focus on process modeling and integration.</p> Aerospace materials Aerospace structures Composite and hybrid materials Process modeling Manufacturing Composites Thermo-viscoelasticity Multi-scale modeling Multi-physics modeling ICME PSPP Thermoset Automated Fiber Placement AFP Optimization Finite Element Analysis FEA Abaqus User-material UMAT Genetic algorithm Process optimization Liquid composites molding Autoclave RTM VARTM LCM Permeability Infusion STAR-CCM+ CFD PAM-RTM Parametric modeling CVM

Search results

Modélisation dynamique de la thermo-viscoélasticité des matériaux bitumeux : Application aux essais FWD sur les structures des chaussées / Dynamic modelling of the thermo-viscoelasticity of bituminous materials : Application to FWD testing on pavement structures

<b>An Integrated Physics-Based Multiscale Modeling Framework for Advancing Thermoset Composites Manufacturing Processes</b>