Concurrently coupled multiscale modeling of polymer nanocomposites

dc.contributorUnnikrishnan, Vinu U.
dc.contributorBarkey, Mark E.
dc.contributorCheng, Gary C.
dc.contributorWang, Jialai
dc.contributor.advisorRoy, Samit
dc.contributor.authorLi, Shibo
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2017-03-01T17:44:40Z
dc.date.available2017-03-01T17:44:40Z
dc.date.issued2016
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractEmbedded statistical coupling method (ESCM) was originally developed to provide computational efficiency, to decrease coupling complexities, and to avoid the need to discretize the continuum model to atomic scale resolution in concurrent multiscale modeling. ESCM scheme is relatively easy to implement within conventional FEM code and has been tested in standard solid lattice structures. However, this method encounters difficulties when being implemented for amorphous materials like polymers, due to the fact that they lack specific ordered lattice structure and atoms may not be covalently bonded with each other, which are the requirements of common coupling schemes. Therefore, a new approach needs to be developed to resolve this problem. In this paper, details of a modified ESCM approach for atomistic-continuum coupling developed to perform simulations of crack growth in polymers is presented. The presence of the continuum domain surrounding the MD region allows for the application of far-field loading, and prevents stress wave reflections from the external boundary impinging back on the crack tip. In our approach, Material Point Method (MPM), which is a meshless particle-in-cell method based on Arbitrary Euler-Lagrange (ALE) scheme and has been proven to have good performance in large deformation problems, is used to model the continuum domain. It is concurrently coupled with molecular dynamics (MD), a widely used method in atomistic simulations, using a so-called handshake region. Anchor points, the equilibrium positions of the constrained particles, which are designed to transmit displacements and forces between nanoscale and macroscale model, are defined in the handshake region. A concurrently coupled MPM-MD simulation of crack propagation inside a polymer is performed to verify this new coupling approach, thereby providing a better understanding of the fracture mechanisms at the nanoscale to predict the macro-scale fracture toughness of polymer system. Results are presented for concurrently coupled crack propagation simulation in a di-functional cross-linked thermoset polymer, EPON 862. The composite laminate open hole tension problem is also studied using concurrent multiscale approach by implementing micromechanics program MAC/GMC in FEA frame.en_US
dc.format.extent100 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0002350
dc.identifier.otherLi_alatus_0004D_12831
dc.identifier.urihttps://ir.ua.edu/handle/123456789/2674
dc.languageEnglish
dc.language.isoen_US
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectAerospace engineering
dc.subjectMechanics
dc.subjectMechanical engineering
dc.titleConcurrently coupled multiscale modeling of polymer nanocompositesen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Aerospace Engineering and Mechanics
etdms.degree.disciplineAerospace Engineering
etdms.degree.grantorThe University of Alabama
etdms.degree.leveldoctoral
etdms.degree.namePh.D.
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