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Polymer and Organic Materials Commons™

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Engineering Science and Materials

Theses/Dissertations

2023

Articles 1 - 8 of 8

Full-Text Articles in Polymer and Organic Materials

Modeling Of Asphalt Concrete For Cross-Anisotropic Visco-Elasticity And Heterogeneity, Zafrul Hakim Khan Dec 2023

Modeling Of Asphalt Concrete For Cross-Anisotropic Visco-Elasticity And Heterogeneity, Zafrul Hakim Khan

Civil Engineering ETDs

Asphalt Concrete (AC) is a cross-anisotropic viscoelastic material. This study has developed a methodology to backcalculate the cross-anisotropic properties of the AC layer from the Falling Weight Deflectometer (FWD) sensor and pavement response data from embedded sensors inside a pavement section. This study has also developed a two-way coupled Multiscale Finite Element Model (MsFEM) with Phase Field Fracture (PFF) to study the microstructural heterogeneity and damage of the AC layer based on the actual field loadings. A Finite Difference Time Domain (FDTD) and Machine learning-based backcalculation algorithm were developed to determine the layer thickness and dielectric constant from air-coupled Ground …

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Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav Dec 2023

Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav

Theses and Dissertations

Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …

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Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams Dec 2023

Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams

All Dissertations

While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …

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Investigating The Rheological Behavior Of A Simple Yield Stress Fluid Under Shear Flows, Francesco Accetta Aug 2023

Investigating The Rheological Behavior Of A Simple Yield Stress Fluid Under Shear Flows, Francesco Accetta

Theses

Many soft materials display unique and complex rheological behavior characterized by a transition from a solid-like to a fluid-like state upon the application of a force that exceeds the threshold to flow, known as the yield stress. Yield stress fluids are found in a wide range of commonly encountered materials including microgels, emulsions, and foams, and have been widely studied by rheologists over the last several decades. Carbopol is a popular polymeric microgel system as it displays simple, non-thixotropic rheological behavior and is typically seen as an ideal yield stress fluid. Previous research has demonstrated the reproducible behavior of shear …

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Numerical Modeling And Simulation On Deformation And Failure Behaviors Of Polymeric Materials, Heng Feng Aug 2023

Numerical Modeling And Simulation On Deformation And Failure Behaviors Of Polymeric Materials, Heng Feng

Electronic Thesis and Dissertation Repository

Featured by biocompatibility, high compliance and capacity in sustaining large deformation, dielectric elastomers (DEs) and hydrogels have gained extensive research popularity for their potential applications in the fields of soft robots, biomimetics, tissue engineering, drug delivery, and energy harvesting. The design of such soft and smart material-based devices and structures requires deep understanding and accurate simulation of their constitutive behaviors, which is challenged by their nonlinear material properties due to unique microstructures and multi-physics coupling. Meanwhile, in different application contexts, those structures are also susceptible to different failure modes, imposing further challenges in simulating and predicting their performance. To fulfill …

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Double Cantilever Beam Mode-I Testing Validation In Large-Scale Additive Manufacturing Carbon Composite, Luis Alfonso Camacho Aug 2023

Double Cantilever Beam Mode-I Testing Validation In Large-Scale Additive Manufacturing Carbon Composite, Luis Alfonso Camacho

Open Access Theses & Dissertations

Testing for mechanical properties for additive manufacturing has been based on already existing standards for traditional manufacturing methods. For composites in large scale additive manufacturing there is a research gap in bond strength and fracture toughness for a single layer interface. By using Double cantilever beam Mode I, this thesis manuscript validates testing parameters and protocols to describe the intricacies of ABS matrix 20 wt.% carbon filled composite, specifically on the layer-to-layer interface. Studies suggest that fracture toughness is sensitive to process parameters, like deflection speed and sharpened crack tip at the layer interface of BAAM 3D printed part and …

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Characterization Of Mechanically Recycled Polylactic Acid (Pla) Filament For 3d-Printing By Evaluating Mechanical, Thermal, And Chemical Properties And Process Performance, Mahsa Shabani Samghabady Aug 2023

Characterization Of Mechanically Recycled Polylactic Acid (Pla) Filament For 3d-Printing By Evaluating Mechanical, Thermal, And Chemical Properties And Process Performance, Mahsa Shabani Samghabady

All Theses

Polylactic acid (PLA) is a biopolymer made from renewable resources such as sugar and corn. PLA filament is a popular material used in Fused Deposition Modeling (FDM) 3D-printing. While this material has many advantages, all the failed parts, support structures, rafts, nozzle tests, and the many prototype iterations during the 3D-printing process contribute to the plastic pollution and release of greenhouse gases. Although PLA is biodegradable, it can take years to degrade in landfills. Instead of throwing away PLA waste and buying new filaments, PLA can be recycled. Amongst the different recycling technologies, mechanical recycling is the most environmentally friendly. …

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Shape Memory Polymer-Based Multifunctional Syntactic Foams, Siavash Sarrafan Apr 2023

Shape Memory Polymer-Based Multifunctional Syntactic Foams, Siavash Sarrafan

LSU Doctoral Dissertations

With the increase in popularity of shape memory polymers (SMPs), especially in applications such as aerospace, textile, biomedical engineering, and even structures, the weight of the material and the devices made with it has always been a crucial factor. Using the shape memory polymer as a matrix to make a syntactic foam is one of the best and most affordable approaches to creating a lighter material that still has the shape memory effect. The addition of particles of different stiffness, strength, and size, with variable fractions, creates a composite that enables engineering the mechanical, as well as other physical and …

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