Cagri Ayranci

Cagri Ayranci
University of Alberta | UAlberta · Department of Mechanical Engineering

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38
Publications
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709
Citations

Publications

Publications (38)
Article
Recent demands for high-performance lightweight materials have brought researchers’ attention to various nanoparticles to reinforce polymeric materials. As such, sustainable and stiff cellulose nanocrystals (CNC) have become a popular candidate as nano-reinforcements. While CNC can offer great advantages, such as high mechanical properties and low...
Article
Full-text available
Nanocomposite technologies can be significantly enhanced through a careful exploration of the effects of agglomerates on mechanical properties. Existing models are either overly simplified (e.g., neglect agglomeration effects) or often require a significant amount of computational resources. In this study, a novel continuum-based model with a stati...
Article
In recent years, investigating lignin as an alternative carbon fiber precursor has received immense research attention as a way to reduce the cost and replace the unsustainable conventional petroleum‐based precursors for carbon fiber production. The predominant challenge for lignin‐based carbon fibers is its low mechanical performance compared to c...
Article
Purpose A review on additive manufacturing (AM) of shape memory polymer composites (SMPCs) is put forward to highlight the progress made up to date, conduct a critical review and show the limitations and possible improvements in the different research areas within the different AM techniques. The purpose of this study is to identify academic and in...
Article
Full-text available
Increasing concerns regarding human-driven effects on the biosphere have led to the development and adoption of environmentally friendly “green” composites. Unlike conventional synthetic composites, green composites are made of natural materials in either the matrix or the fiber reinforcement (or both). They are claimed to have lower negative envir...
Article
Braiding is an advanced textile manufacturing method that is used to produce two-dimensional and three-dimensional components. Unlike laminated structures, braids have interlaced yarns that form a continuity between layers. This structure allows for improved impact resistance, damage tolerance, and improved through-thickness reinforcement. Despite...
Article
Full-text available
This study aims to assess the effect of printing parameters on the final tensile properties of 3D printed specimens printed through a popular vat-photopolymerization printer—‘Form 2’. Elastic modulus, ultimate tensile strength and strain at break are analyzed as a function of process parameters in order to provide an optimized print parameter confi...
Article
Nitrobenzene (CNC‐1), trifluoromethyl benzene (CNC‐2) modified and polystyrene‐grafted (CNC‐g) cellulose nanocrystals in polystyrene (PS)‐N,N dimethylformamide (DMF) solutions were electrospun and collected as stretched and aligned fibers on a rotating drum. Scanning electron microscope pictures showed significant alignment in the case of unmodifie...
Article
There is an increasing demand for the use of “green”-based materials as reinforcement and matrix materials in composites. However, the ability of these natural-based materials to perform as consistently and reliably as conventional materials is still relatively unknown. A key importance in the viability of these materials is the evaluation of the c...
Article
Full-text available
Extrusion-based additive manufacturing (EBAM) or 3D printing is used to produce customized prototyped parts. The majority of the polymers used with EBAM show moisture sensitivity. However, moisture effects become more pronounced in polymers used for critical applications, such as biomedical stents, sensors, and actuators. The effects of moisture on...
Article
Full-text available
In this article, the electrospinning process for Silica nanoparticles reinforced Nylon 6 nanofiber composite mats is investigated. More specifically, the effect of Nylon 6/Formic Acid concentration and silica weight fraction on the solution viscosity and the properties of the end product is studied. Rheological measurements were conducted to invest...
Article
Shape memory materials are an innovative type of materials that reversibly store a temporary shape and recover back to the original dimensions with the application of an external mechanism such as heat. Shape memory polymers (SMP), specifically thermoplastic SMP (e.g. shape memory polyurethane (SMPU)) have received much attention during the past de...
Article
Purpose This paper aims to present an investigation of material-process interaction of VAT-photopolymerization processes. The aim of the research is to evaluate the effect of different printing factors on the tensile properties, such as elastic modulus, of 3D printed specimens. Design/methodology/approach To perform this study, Design of Experim...
Conference Paper
Full-text available
Braided composites are formed by interlacing continuous fibers into a textile pre-form and then impregnating the pre-form within a matrix material. Braid mechanical properties are manipulated through the selection of matrix, fiber and braid geometry. Braided composites are produced with conventional materials like carbon, aramid and glass fibers; h...
Article
Full-text available
Multi-layer structures with functionalities, varying height channels, complex microfluidic structures like valves, mixers and high aspect ratio channels (hereby referred as 3D-Microfluidics) are very difficult to fabricate using conventional microfluidics fabrication methods. On the other hand, high geometric complexity, less manufacturing time, lo...
Article
This study investigated the electrospinning of polystyrene solutions using added unmodified and modified (with grafted nitrobenzene and trifluoromethyl benzene functionalities and polystyrene brushes) cellulose nanocrystals (CNCs). A strong correlation existed between the formation of beads on the fibers and the degree of dispersion of CNC particle...
Article
Full-text available
OSM-Classic is a program designed in MATLAB ® to provide a method of accurately determining strain in a test sample using an optical imaging technique. Measuring strain for the mechanical characterization of materials is most commonly performed with extensometers, LVDT (linear variable differential transistors), and strain gauges; however, these st...
Article
In this study, a sulfur-free softwood lignin (SFSL) was electrospun to form bead-free fibers. The fibers were evaluated as potential precursors for carbon fiber production. Higher heating rates of thermo-stabilization caused afused fiber morphology. The lignin purification process also affected the quality of the SFSL-based carbon fibers. Therefore...
Article
The fracture of high molecular weight poly(ethylene oxide) (PEO) chains under extensional stretching during the electrospinning of aqueous solutions was investigated by measuring solution viscosities and monitoring the change of molecular weight. The degree of macromolecular chain fractures in 1.0% polymer solutions increased with the increase in m...
Article
Material extrusion additive manufacturing (MEAM), a sub-branch of three- dimensional (3D) printing is growing in popularity. Test specimens were 3D-printed using commercial polylactic acid (PLA) filament, and PLA filament reinforced with short-carbon fibers (PLA/CF). As-printed specimens and specimens that were annealed at three different temper...
Article
Traditional steel rebar used for concrete reinforcement can be susceptible to corrosion. One solution to this problem is to substitute fiber reinforced polymer (FRP) rebar in the place of steel. However, conventional unidirectional FRP rebars are limited by a linear elastic failure mode at relatively low ultimate strains. In this study, FRP rebar w...
Article
Electrospinning of sulfur-free softwood lignin (SFSL) in N,N-dimethylformamide (DMF) is reported as is and with poly(ethylene oxide) (PEO). SFSL macromolecules behave as rigid spheres, instead of free draining macromolecules in DMF. Hence they are investigated as colloids. Colloidal SFSL generates uniform fibers only at the volume fraction of 0.63....
Article
Fiber reinforced polymer (FRP) rebar can serve as a noncorrosive alternative to conventional steel rebar for use in concrete reinforcement. By combining pultrusion and braiding into a single manufacturing process called braidtrusion, FRP rebar consisting of both unidirectional and off-axis fibers can be produced. In this study, a variation on the b...
Article
Material extrusion additive manufacturing (MEAM), also known as three-dimensional (3D) printing, is a popular additive manufacturing technique suitable for producing 3D shapes using thermoplastic materials. The majority of companies that design and test 3D printing machines work with thermoplastic acrylonitrile butadiene styrene (ABS) and polylacti...
Article
This study reports a method to achieve dispersion of freeze-dried Cellulose nanocrystals (CNCs) with polyvinylpyrrolidone (PVP) in a water-methanol cosolvent system using purely mechanical means; in this case, magnetic stirring and sonication. During this study, no chemical modifiers or surfactants of any kind were added during the dispersion proce...
Article
The development of nonwoven meshes based on cellulose acetate (CA) reinforced by cellulose nanocrystals (CNC) is reported. The meshes were electrospun from 15 wt% CA (Mn = 30,000) in dimethylacetamide/acetone (1:2, w/w) solutions with various concentrations of CNC dispersions. The investigated six levels of CNC dispersions in CA solutions were: 0,...
Article
Full-text available
Student evaluation of teaching (SET) hasbeen used as a metric to arguably evaluate instructoreffectiveness and quality of instruction since the 1920s.SET is used in decisions regarding annual evaluation (offaculty) and is one of the most researched topics inevaluation of instructor effectiveness. Central researchquestions associated with SET includ...
Chapter
Textile braiding and composites production have been carried out throughout human history. In this article we focus on a review of two- and three-dimensional braiding processing and mechanical performance, discuss available predictive modeling techniques, and discuss the advantages and disadvantages of braiding as it relates to other similar manufa...
Article
The prediction of elastic constants of open-mesh diamond braids has not been adequately studied. The objective of this work is to provide a further comparison of longitudinal elastic and shear moduli regression equations previously developed with experimental data from in-house experiments; to determine the regression equations linearity limits; an...
Article
Conventional applications of two-dimensional tubular braided composites mostly require closed-mesh braiding; however, some stiffness-critical applications may require use of open-mesh braiding. Most likely candidates for the open-mesh braided composites are in the medical field, such as braided catheters and stents. Analytical and experimental inve...
Article
A thorough understanding of 2D braided composites elastic behavior is necessary for stiffness critical applications. This article outlines the effects of radius of curvature of a unit cell on 2D braided tubular composites’ elastic constants via a sensitivity study. The proposed model is verified using literature and experimental results. The propos...
Article
Predicting the elastic constants of braided composites has gained increasing importance over the years. This is mostly due to the broad use of the braided composites and the need to accurately predict their response during stiffness critical applications. This paper outlines an analytical study to predict longitudinal elastic modulus of two-dimensi...
Article
Two-dimensionally (2D) braided tubular composites have been utilized in a wide range of applications including medical equipment such as braided stents and catheters. Catheters are long flexible tubes used in catheterization procedures, such as angiography and ablations. In this thesis, angiographic catheters were specifically targeted; which are r...
Article
Composite materials offer numerous advantages over conventional engineering metals. Over the years, the use of composite materials has increased significantly. Braiding is a promising and already very commonly used method to form continuous fiber reinforced composite materials. Braided structures are used in a broad range of applications including,...

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