Print Email Facebook Twitter Finite Element Model For Interfaces In Compatibilized Polymer Blends Title Finite Element Model For Interfaces In Compatibilized Polymer Blends: A Comparative Study on the Mixed-Mode Response of Cohesive Zone Models Implemented With Small and Large Displacement Assumptions Author Mudunuru, Nanditha (TU Delft Mechanical, Maritime and Materials Engineering) Contributor Bessa, M.A. (mentor) Turon Travesa, Albert (graduation committee) Chen, B. Y. (graduation committee) Degree granting institution Delft University of Technology Programme Materials Science and Engineering Project VENI Date 2022-03-30 Abstract Designing and modeling compatibilized polymer blends require accurate interface model. In addition, it is possible that crazing occurs during failure of the interfaces leading to large deformation prior to complete failure and therefore must be accounted for by the interface model.A preliminary literature review showed that existing formulations for the largedeformation account for the nonlinearity by adjusting the assumptions. For example, Van den Bosch et al. (2007) proposed redefining the local basis at each integration point. In contrast, Reinoso and Paggi (2014) argued that this did not account for geometric nonlinearity and proposed including the first derivative of rotation vector in the finite element equation. However, the mixed-mode responses of the models were not characterized and validated thoroughly. Therefore, we studied the response from standardized mixed-mode tests to compare the large displacement formulation with the commonly used small-displacement formulation of the cohesive zone model.The standardized tests used by Moreira et al. (2020) for characterizing the mixed-mode behavior of ductile interfaces inspired the tests used in this study. When implemented with the BK criteria, the mode partitioning method used by Moreira et al. (2020) results in a wider spread of the mean predicted mode ratio and the mean predicted fracture toughness. However, the corresponding mode ratio predictions are similar when the predicted fracture toughness is close to expected. Therefore, while the power-law is better for implementing the mode partitioning method, we can use the predictions from the mode partitioning method implemented with the power-law to find the BK parameter. Further, simulating the mixed-mode fracture tests with properties presented byMoreira et al. (2020) showed that bulk materials with high modulus or stiffness, such as carbon fiber reinforced plastics, do not undergo nonlinear deformation to require the large deformation formulation. However, for bulk materials with lower modulus or stiffness, the responses of the two formulations in question are different. Additionally, for a given load case, a cohesive zone with anisotropic fracture properties experiences a different mode ratio when implemented with the large displacement formulation than the small displacement formulation. Moreover, more significant influence of the stronger mode on the load case results in greater difference between the mode ratio experienced at the interface. Nevertheless, the large displacement formulation is also applicable for stronger mode-II interfaces. However, a further investigation involving physical experiments is required to compare the response of the two formulations to the behavior of real material systems. Subject Cohesive Zone ModelingFinite Element MethodABAQUSPolymer InterfaceCrazingLarge DeformationUser Element (UEL) SubroutineStandarized testsMixed-mode CharacterizationInterface CharacterizationMode Partitioning Methodczmtestkit To reference this document use: http://resolver.tudelft.nl/uuid:88140513-120d-4a34-b893-b84908fe2373 Bibliographical note ISBN 978-94-6366-528-5 https://pypi.org/project/czmtestkit/ Python Package Index for czmtestkit developed for the project https://czmtestkit.readthedocs.io/en/latest/index.html Documentation for the PyPI package named czmtestkit Part of collection Student theses Document type master thesis Rights © 2022 Nanditha Mudunuru Files PDF Nanditha_Thesis_1_.pdf 5.09 MB Close viewer /islandora/object/uuid:88140513-120d-4a34-b893-b84908fe2373/datastream/OBJ/view