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Enhanced Computational Homogenization and Phase-Field Fracture Approaches for Polymer Nano-Composites = = Erweiterte numerische Homogenisierungsund Phasenfeld-Bruch-Ansatze furPolymer-Nanokomposite.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Enhanced Computational Homogenization and Phase-Field Fracture Approaches for Polymer Nano-Composites =/
其他題名:	Erweiterte numerische Homogenisierungsund Phasenfeld-Bruch-Ansatze furPolymer-Nanokomposite.
作者:	Kumar, Paras.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2024,
面頁冊數:	216 p.
附註:	Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
Contained By:	Dissertations Abstracts International85-12B.
標題:	Mechanical properties. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31212469
ISBN:	9798383070994

Enhanced Computational Homogenization and Phase-Field Fracture Approaches for Polymer Nano-Composites = = Erweiterte numerische Homogenisierungsund Phasenfeld-Bruch-Ansatze furPolymer-Nanokomposite.
Kumar, Paras.

Enhanced Computational Homogenization and Phase-Field Fracture Approaches for Polymer Nano-Composites =Erweiterte numerische Homogenisierungsund Phasenfeld-Bruch-Ansatze furPolymer-Nanokomposite. - Ann Arbor : ProQuest Dissertations & Theses, 2024 - 216 p.

Source: Dissertations Abstracts International, Volume: 85-12, Section: B.

Thesis (Ph.D.)--Friedrich-Alexander-Universitaet Erlangen-Nuernberg (Germany), 2024.

Polymers reinforced with inorganic filler particles of different shapes and sizes, play a prominent role as constituent materials for structural components in a plethora of applications ranging from rubber tires to biomedical implants. A relatively new class of this omnipresent family of engineering materials includes polymer nano-composites wherein at least one of the dimensions of the filler particles is of the order of nanometers. The superior reinforcement efficacy of nanosized fillers in enhancing the elastic and fracture behavior of the base polymer, in comparison to their conventional microsized counterparts, has been corroborated by several experimental investigations. The aforementioned superior mechanical response, also characterized as the smaller is stronger size effect, results from the formation of interfacial regions or interphases around filler particles, having properties drastically different from those of the polymer matrix, which is much more prevalent in case of nanosized fillers, owing to the much larger specific surface area they afford. Standard two-phase continuum modeling approaches are unable to capture this size effect since they lack the requisite length scale and appropriate enhancementsor extensions are, therefore, necessary.This thesis is concerned with the development of enhanced continuum modeling approaches which can accurately capture the mechanical response of polymer nano-composites. A generic finite-deformation setting is adopted since it enables the modeling of a wide range of polymer composites undergoing large strains prior to fracture. Within the hyperelastic or pre-fracture regime, two enhancements of the standard first-order computational homogenization scheme are investigated in detail, one of which is based on the theory of interface energetics and the other rooted in the physically motivated concept of graded interphases. The former technique includes lower dimensional energetic interfaces possessing their own energetic structure, alike the bulk, at the filler-matrix intersections. The latter, on the other hand, entails a continuous variation or grading in material properties within an interphase region of finite thickness around the filler particles. Extensive numerical experimentation demonstrates the graded-interphase based approach as the better suited candidate for modeling the hyperelastic response of polymer nano-composites with different filler-matrix stiffness contrasts, under generic loading scenarios. Transitioning to the fracture regime, the phase-field fractureapproach, by virtue of its innate ability to handle complex track topologies, is chosen as the basis for further development geared towards modeling crack nucleation and propagation in polymer nano-composites. The graded-interphase concept is combined with the phase-field fracture approach to enable the modeling of a wide spectrum of microscopic fracture responses including different effective fracture behaviors and even particle debonding as commonly observed in case of polymer nano-composites. The developed methodology is also applied to realistic multi-particle micro-structures.

ISBN: 9798383070994Subjects--Topical Terms:

3549505
Mechanical properties.

Enhanced Computational Homogenization and Phase-Field Fracture Approaches for Polymer Nano-Composites = = Erweiterte numerische Homogenisierungsund Phasenfeld-Bruch-Ansatze furPolymer-Nanokomposite.
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245 1 0 $a Enhanced Computational Homogenization and Phase-Field Fracture Approaches for Polymer Nano-Composites = $b Erweiterte numerische Homogenisierungsund Phasenfeld-Bruch-Ansatze furPolymer-Nanokomposite.
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300 $a 216 p.
500 $a Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
500 $a Advisor: Mergheim, Julia;Kaliske, Michael.
502 $a Thesis (Ph.D.)--Friedrich-Alexander-Universitaet Erlangen-Nuernberg (Germany), 2024.
520 $a Polymers reinforced with inorganic filler particles of different shapes and sizes, play a prominent role as constituent materials for structural components in a plethora of applications ranging from rubber tires to biomedical implants. A relatively new class of this omnipresent family of engineering materials includes polymer nano-composites wherein at least one of the dimensions of the filler particles is of the order of nanometers. The superior reinforcement efficacy of nanosized fillers in enhancing the elastic and fracture behavior of the base polymer, in comparison to their conventional microsized counterparts, has been corroborated by several experimental investigations. The aforementioned superior mechanical response, also characterized as the smaller is stronger size effect, results from the formation of interfacial regions or interphases around filler particles, having properties drastically different from those of the polymer matrix, which is much more prevalent in case of nanosized fillers, owing to the much larger specific surface area they afford. Standard two-phase continuum modeling approaches are unable to capture this size effect since they lack the requisite length scale and appropriate enhancementsor extensions are, therefore, necessary.This thesis is concerned with the development of enhanced continuum modeling approaches which can accurately capture the mechanical response of polymer nano-composites. A generic finite-deformation setting is adopted since it enables the modeling of a wide range of polymer composites undergoing large strains prior to fracture. Within the hyperelastic or pre-fracture regime, two enhancements of the standard first-order computational homogenization scheme are investigated in detail, one of which is based on the theory of interface energetics and the other rooted in the physically motivated concept of graded interphases. The former technique includes lower dimensional energetic interfaces possessing their own energetic structure, alike the bulk, at the filler-matrix intersections. The latter, on the other hand, entails a continuous variation or grading in material properties within an interphase region of finite thickness around the filler particles. Extensive numerical experimentation demonstrates the graded-interphase based approach as the better suited candidate for modeling the hyperelastic response of polymer nano-composites with different filler-matrix stiffness contrasts, under generic loading scenarios. Transitioning to the fracture regime, the phase-field fractureapproach, by virtue of its innate ability to handle complex track topologies, is chosen as the basis for further development geared towards modeling crack nucleation and propagation in polymer nano-composites. The graded-interphase concept is combined with the phase-field fracture approach to enable the modeling of a wide spectrum of microscopic fracture responses including different effective fracture behaviors and even particle debonding as commonly observed in case of polymer nano-composites. The developed methodology is also applied to realistic multi-particle micro-structures.
520 $a Polymere, die mit anorganischen Fullstoffpartikeln unterschiedlicher Formen und Grosen verstarkt sind, spielen eine herausragende Rolle als Werkstoffe fur Strukturbauteile in zahlreichen Anwendungen, von Autoreifen bis zu biomedizinischen Implantaten. Eine relativ neue Klasse dieser Werkstofffamilie sind Polymer-Nanokomposite, bei denen mindestens eine der Partikelabmessungen in der Grosenordnung von Nanometern liegt. Im Vergleich zu konventionellen mikroskopischen Partikeln fuhren nanoskalige Fullstoffe zu einer ausgepragteren Verbesserung des Elastizitats- und Bruchverhaltens, wie durch zahlreiche experimentelle Untersuchungen bestatigt. Die Bildung von Grenzschichten oder Interphasen um die Fullstoffpartikel, deren Eigenschaften sich drastisch von denen der Polymermatrix unterscheiden, ist bei Fullstoffen im Nanobereich aufgrund deren viel groseren spezifischen Oberflache weitaus ausgepragter und fuhrt zu dem oben erwahnten besseren mechanischen Verhalten, das auch als "kleiner ist starker"-Effekt bezeichnet wird. Standardmasige Zweiphasen-Kontinuumsmodellierungsansatze sind nicht in der Lage diesen Groseneffekt zu erfassen, da ihnen die erforderliche Langenskala fehlt, wodurch entsprechende Erweiterungenoder Erganzungen erforderlich sind.Diese Arbeit befasst sich mit der Entwicklung erweiterter Kontinuumsmodellierungsansatze, die das mechanische Verhalten von Polymer-Nanokompositen zuverlassig beschreiben konnen. Es wird ein generischer Ansatz fur grose Deformationen gewahlt, da er die Modellierung eines breiten Spektrums von Polymerkompositen ermoglicht, die ublicherweise vor dem Bruch grosen Verzerrungen ausgesetzt sind. Innerhalb des hyperelastischen Bereichs werden zwei Erweiterungen der klassichen numerischen Homogenisierung erster Ordnung im Detail untersucht, von denen eine auf der Theorie der Grenzflachenenergetik und die andere auf dem physikalisch motivierten Konzept der gradierten Interphasen beruht. Bei der ersten Methode werden zwischen Fullstoff und Matrix niederdimensionale energetische Grenzflachen eingebaut, die eine eigene energetische Struktur entsprechend einem Feststoff besitzen. Beim zweiten Konzept hingegen werden die Materialeigenschaften innerhalb eines endlich ausgedehnten Interphasenbereichs um die Fullstoffpartikel herum kontinuierlich verandert oder gradiert. Umfangreiche numerische Untersuchungen zeigen, dass das Konzept der gradierten Interphasen geeigneter fur die Modellierung des hyperelastischen Verhaltens von Polymer-Nanokompositen mit unterschiedlichen Fullstoff-Matrix-Steifigkeitskontrasten unter allgemeinen Lastfallen ist. Fur den Ubergang zum Bruchverhalten wird der Phasenfeldansatz als Grundlage fur die weitere Entwicklung gewahlt, da er in der Lage ist, die komplexen Risstopologien abzubilden, die ublicherweise in Polymer-Nanokompositen auftreten. Das Konzept der gradierten Interphasenwird mit dem Phasenfeldansatz fur Bruchprozesse kombiniert, um die Modellierung eines breiten Spektrums von mikroskopischen Bruchverhalten zu ermoglichen, einschlieslich einer Reihe von effektiven Bruchverhaltensweisen und sogar der Partikelablosung wie es im Fall von Polymer-Nanokompositen haufig beobachtet wird. Die entwickelte Methode ist auch bei realistischen Multi-Partikel-Mikrostrukturen anwendbar.
590 $a School code: 0575.
650 4 $a Mechanical properties. $3 3549505
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