Aerospace Engineering Commons^™

A Cfd-Dem Framework For Characterizing Nanoparticle Adhesion Effects On Creeping-Flow Permeability In Composite Manufacturing, Gavin Stoker

All Graduate Theses and Dissertations, Fall 2023 to Present

Modern aircraft, spacecraft, and high-performance vehicles are increasingly built from composite materials, engineered combinations of plastics and fibers that are lighter and stronger than traditional metals. Researchers are now pushing these materials further by mixing in microscopic particles thousands of times smaller than a human hair, called nanoparticles, to make them even tougher and more resistant to damage. The challenge is getting those nanoparticles distributed evenly. During manufacturing, liquid plastic resin is pumped through a network of tightly packed fibers, carrying the nanoparticles along with it. But nanoparticles tend to clump together and stick to surfaces as they travel, clogging …

Aerodynamic Design And Structural Evaluation Of A Global Minimum Torque Inspired Multirotor Propeller, Zeke Bukovansky

Master's Theses

This thesis develops a repeatable design, CAD, aerodynamic postprocessing, structural screening, and manufacturing feasibility workflow for a 22-inch global minimum torque inspired multirotor propeller. Matched MIL and GMT geometries were compared at a 35 N, 4000 rpm static-hover operating condition using BEMT/XFOIL aerodynamic postprocessing, with diameter, blade count, chord distribution, airfoil schedule, and target thrust held constant. The final modeled comparison predicted a modest 1.5% reduction in torque and shaft power for the GMT case while maintaining the same thrust target. CAD construction, MATLAB reduced-order beam model, Abaqus screening, and manufacturing planning were used to identify geometry level structural and …

Experimental Investigation Of Mode-Ii Interlaminar Fatigue Damage In Stitched And Unstitched End-Notched Flexure Carbon Fiber Composites, Madelyn Sloan Berry

Honors Theses

Composite materials are increasingly used in aerospace structures due to their high strength-to-weight ratio, but their susceptibility to interlaminar fatigue damage remains a critical concern, particularly under mode-II shear loading. This study investigates the fatigue behavior of stitched and unstitched quasi-isotropic carbon fiber composite specimens made of SAERTEX Class-75 non-crimp fabrics and Hexcel 1078-1 epoxy via vacuum assisted resin transfer molding. Global fatigue behavior was analyzed using displacement and crack length cycle relationships derived from compliance calibration methods (CCM), while local behavior was examined using digital image correlation (DIC). Unstitched specimens exhibited a single rapid crack growth associated with unstable …

Enhancing Nasa Sounding Rocket Capabilities Through Composite Material Adoption, Robert Burth

Mechanical & Aerospace Engineering Theses & Dissertations

Sounding rockets are a suborbital research platform employed by NASA for heliophysics, astrophysics, geospace science investigations, and for technology development. They follow semi-parabolic trajectories and are launched using surplus military, and commercial, solid-propellant rocket motors. NASA sounding rocket payloads are comprised of standard, modular subassemblies, designed to perform specific functions critical to achieving specific mission success criteria.

Since the program’s inception, payload length and mass have trended upwards, limiting the capability of the platform to reach exospheric apogees and decreasing the time above critical altitudes to observe solar and celestial targets. To offset this trend, composite materials may be of …

Detecting And Repairing Conflicting Constraints In Co-Trained Physics-Informed Neural Networks For Composite Curing Processes, Cooper J. Evans

Dissertations, Master's Theses and Master's Reports

Composite materials have become a critical component of modern manufacturing, especially in the automotive and aerospace industries. The curing process for these composites has been modeled using a variety of partial differential equations representing the heat transfer and composite curing kinetics. Optimizing the applied temperature profile is critical for maximizing the efficiency and capacity of composite part manufacturers. Constraints must be placed on the inputs and outputs of the model, including but not limited to, the applied temperature profile, part temperature, and final degree of cure. Conflicting sets of constraints are easy to unknowingly impose due to the highly coupled …

Engineering Of Metallic Interpenetrating Phase Composites For The Control Of Deformation And Failure Modes During Dynamic Events, David Kiyoshi Santacruz

Open Access Theses & Dissertations

Aerospace components, automotive structures, and ballistics armor are all engineered to withstand high strain rate service events through a combination of material selection and design choices. However, structural components may be less effective when their implementation is constrained by other factors such as weight or design limitations. To meet these challenges, the development of next-generation materials will need to increasingly rely on composite material systems rather than monolithic materials. This thesis presents the fabrication, dynamic characterization testing, and post-mortem analysis of 316L/A356 interpenetrating phase composites (IPCs) made from the PrintCasting methodology. These composites consist of additively manufactured 316L stainless steel …

Experimental And Theoretical Fracture Analysis Of Rift Manufactured Carbon Fiber-Vinyl Ester Lamina, Daniel Joseph Longo

Theses and Dissertations

This thesis investigates the fracture behavior of unidirectional carbon fiber-vinyl ester (CFVE) laminates manufactured using the Resin Infusion with Flexible Tooling (RIFT) process, a cost-effective alternative to autoclave-based fabrication methods. Composite materials like CFVE are increasingly adopted in high-performance applications due to their high strength-to-weight ratio and corrosion resistance; however, their anisotropic nature presents challenges in predicting crack initiation and propagation. To address this, a comprehensive approach combining experimental testing, finite element modeling (FEM), and classical fracture mechanics was employed. Orthotropic mechanical properties were first determined through tensile and shear tests, providing critical properties for FEM simulations. A series of …

Characterizing Intralaminar Distal Crack And Delamination In Multidirectional Laminates Under Low Velocity Impact: Modeling Approach With Ultrasound Testing Validation, Niildiip Chandraa, Rachel Van Lear, Arief Yudhanto, Yuqing Zhao, David A. Jack, Douglas E. Smith

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multidirectional laminated composites are essential for load-bearing structures, especially under frequent impact loading. While existing modeling techniques simulate various impact damage modes, our understanding of the underlying mechanisms, specifically the initiation and progression of intralaminar distal cracks and interlaminar delamination, needs improvement. Validating these mechanisms is crucial for enhancing modeling accuracy and expediting the design process. In this work, we propose a three-dimensional finite element modeling (3D FEM) approach aimed at elucidating the impact damage mechanisms in multidirectional carbon fiber reinforced polymer (CFRP). Our model incorporates cohesive zone models (CZM) to simulate the behavior of intralaminar cracks at distal points …

Evaluation Of Impact Energy In Composites Using Acoustic Emission Sensing Technique, Li Ai, Tanner Mesaric, Sydney Flowers, Sydney Houck, Joshua Widawsky, Paul Ziehl

Faculty Publications

A major challenge faced by composite materials is impact, which can result in unexpected damage and degradation. Impact events can cause significant structural damage that may not be immediately visible, leading to a reduction in the material’s mechanical properties and overall performance. This paper presents an impact assessment method using acoustic emission (AE) sensing technology. The primary goal of this approach is to determine the extent of impact damage on composite components by analyzing AE signals produced under operating stress conditions. An advanced algorithm is proposed to predict the probability that the damage falls into various damage categories, providing a …

Performance Of Multi-Composite Materials With Corrugated And Cell Geometries Under Low-Velocity Impact, Lukas S. Kolbl

Master's Theses

Composite structures have demonstrated great potential to improve mechanical performance in various applications, including ballistics protection. This study demonstrates that the integration of geometrically optimized composites into core-face sheet assemblies provide great impact resistance. The research investigated the performance of two composite manufacturing methods under low-velocity impact through residual strength and damage comparisons. Corrugated core composites were produced with traditional manufacturing methods, namely compression molding, using twelve stacking sequences. These stacking sequences were chosen to represent four laminate groups, where a unique fiber orientation scheme was employed across three laminate thicknesses (6, 8, and 12 layers). In contrast, honeycomb and …

Multiscale Analysis Of Thermal Barrier Coated Cfrp Composites Under Thermal Loading, Devin Nielsen, Trenton M. Ricks, Juhyeong Lee

Mechanical and Aerospace Engineering Student Publications and Presentations

Carbon-fiber reinforced polymer (CFRP) composites are commonly used in high performance applications. Although offering several advantages (i.e., superior specific properties and improved structural rigidity), traditional CFRP composites often exhibit poor thermal stability due to a low matrix thermal decomposition temperature. The effective operating temperature of the CFRP composites can be raised by applying an outermost, protective thermal barrier coating (TBC) layer. Prefabricated high void content ceramic TBCs are ideal for composite applications due to their high thermal stability and relatively low thermal conductivity. In this paper, the thermo-mechanical response of the TBCCFRP composite laminate subjected to 500°C are assessed through …

High-Rate Production Of Thermoplastic Composite Structures For Urban Air Mobility Vehicles Utilizing Fastener-Free Assembly Methods, Robert H. Shumpert

Theses and Dissertations

This study aimed to develop a manufacturing plan for a Thermoplastic fiber-reinforced propeller blade for urban air mobility applications. This propeller blade offer a few unique challenges including the complex geometries of the blade. Another important aspect of the blade is using fusion bonding methods to increase the strength of joints in the product while reducing weight from fasteners and adhesives. This manufacturing process will be validated by producing a physical demonstrator to ascertain the efficacy of the manufacturing techniques used. First, the techniques that will make up the manufacturing plan must be selected. To do this, a review of …

Team F16: Autonomous Research Plane, Andrew Sugamele, Andrew Whitacre, Nicholas Toal, Cole Bushur

Mechanical Engineering

The autonomous research plane is a remote-controlled plane used for both in-flight data collection and to explore new manufacturing methods for Design Build Fly, an engineering club on campus. The club does not have the resources or time to implement data collection for their competition plane, so we built a plane in parallel, following similar rules to mimic the work and schedule that the club would use during their season. We first did research and analysis to determine the structure of the plane, geometry of wings, sizing of the tail, and what airfoil to choose. The manufacturing process included making …

Damage Control Measures In Composites: Focus On Damage Tolerance Of Aerospace Structures, Kais Jribi

Doctoral Dissertations and Master's Theses

Barely Visible Impact Damage (BVID) in composite materials presents a stealthy yet significant risk to structural integrity, particularly challenging due to its elusive nature. The approach adopted here diverges from traditional methodologies, focusing on the novel application of Digital Image Correlation (DIC) to map surface area changes during in-situ Compression After Impact (CAI) tests. This technique allows for an in-depth analysis of planar strains along the x and y axes, shedding light on the material's behavior under stress.

A pivotal advancement lies in developing a method for precisely identifying when BVID-induced delamination recommences. By meticulously analyzing strain pattern deviations along …

Kissing Bond Assessment In Adhesive Bonded Carbon Fiber Reinforced Composites Using Dielectric Spectroscopy, Minhazur Rahman

Mechanical and Aerospace Engineering Dissertations - Archive

The widespread use of fiber-reinforced composites in industries such as space, aviation, automobiles, and construction necessitates the formation of robust composite joints between critical structural components. Although adhesive-bonded joints are superior with improved load distribution and reduced weight, they are often overlooked in favor of bolted joints and mechanical fasteners due to the lack of reliable Non-Destructive Evaluation (NDE) techniques for adhesive-bonded composites. The anisotropic nature of the substrate and the intricate interfacial interactions between the adherend and adhesive material present significant challenges for conventional NDE methods. Moreover, weak adhesive bonds can result from uncontrolled manufacturing parameters, such as accidental …

Interfacial Thermomechanical Behavior Of Hybrid Carbon Fibers, Sriraj Srihari

Doctoral Dissertations and Master's Theses

The carbon fiber/epoxy interface is of great importance in composite design due to its load transfer mechanisms from the weak epoxy to the stronger fiber. Improving the strength of the interface reduces the risk of failure at the interface and improves the load transfer to the fiber. In this study, two types of nano-species ZnO nanowires and nickel-based metal organic frameworks were grown on carbon fibers to improve the interfaces. The interfacial mechanics of the enhanced fibers are evaluated using nanoindentation studies. Composite samples with Aeropoxy matrix and vertically aligned fibers are fabricated for this purpose. A Bruker TI-980 TriboIndenter …

The Effect Of Through Thickness Reinforcement Angle On The Disbonding Behavior In Skin-Stringer Configuration, Christopher John Morris

Mechanical & Aerospace Engineering Theses & Dissertations

Post-cure through thickness reinforcement is a method used to increase the mechanical properties of composite laminates in the transverse direction. This study conducted a test on skin-stringer structures bonded together in three configurations using an epoxy or thermoplastic adhesive at the interface with reinforcing pins inserted through the laminate thickness located at the edge of the stringer at differing angles between -30º and 30º. The fabrication of these samples in configurations B and C consisted of the use of carbon fiber prepeg laminate at a ply orientation of [0₂90₂]_2s for the skin and [0 90] …

Composite Solid Rocket Motor Case Optimization With Matlab Genetic Algorithm, Aleksandr Breit

Master's Theses

This study utilizes MATLAB genetic algorithm (GA) to perform optimization on a solid rocket motor (SRM) chamber structure. The (SRM) structure is modelled as a cylindrical composite laminate where unidirectional fiber orientations are the primary design variable in the optimization problem formulation. Additional design variables such as chamber length, diameter, and internal pressure are altered along with the ply angles to minimize the safety margin towards a near-zero value and encourage efficient layup design. Classical lamination theory with Tsai-Wu failure criterion are used to calculate ply-level safety margins. A thickness minimization scheme is employed to reduce the ply count from …

Study Of A Carbon Fiber Reinforced Polymer Composite Using A Biobased Polyurethane As A Thermosetting Resin, Teddy Mageto

Electronic Theses & Dissertations

Carbon Fiber Reinforced Polymer composites (CFRP) have garnered increasing interest in recent years especially in the aerospace and automobile industries where they are gradually replacing metals as structural materials. This is owing to their light weight, high strength, high modulus, and excellent strength-to-weight ratio. Polymers are typically used as thermosetting resins in these composites. However, the synthesis of polymers currently is conducted via petrochemical processes which leads to adverse effects on the environment. To this end, in this work a biobased Polyurethane (PU) was used as a thermosetting resin in a CFRP. The biobased PU was synthesized by the reaction …

Effects Of Metal Organic Frameworks In Polyether Block Amide Elastomer, Joe Alex

Mechanical and Aerospace Engineering Theses - Archive

Metal-organic frameworks (MOFs) are highly porous materials that find extensive applications in gas absorption and separation in recent years. These hybrid materials can be designed with specific pore sizes and voids to selectively filter gases. PEBAX (MV 1074) is a commercially available polyether block amide copolymer generally used in gas separation applications. In this study, we characterize two different MOFs by means of a dispersion study and create a medium for them to be evenly dispersed into the aforementioned copolymer matrix. Polymer composite fibers are extruded using a twin-screw extruder and a winding unit at pre-determined parameters for winding speed …

Fatigue Performance Modeling In Advanced Out-Of-Autoclave Composites For Aerospace Applications, Grayson Reid Curry

Mechanical and Aerospace Engineering Theses - Archive

Increased application of composite materials in the military and civil applications renewed the interest to development of high-fidelity methodologies for predicting their performance characteristics. Besides the traditional autoclave processed structural composites such as IM7/8552 and IM7/977-3 widely used on various platforms, novel materials such IM7/5320-1 suitable for Out-of-Autoclave (OoA) cure became of interest. Static and fatigue performance prediction of Open-Hole quasi-isotropic laminates made from IM7/5320-1 was performed in this work by using the Finite Element Analysis software BSAM. Progressive failure simulation including delaminations, matrix cracks and fiber failure was performed. Regularized eXtended Finite Element Methods (RXFEM) was used for mesh …

Fusion Bonding Behavior Of 3d Printed Pa6/Cf Composites Via Post Fabrication Compaction, Gonzalo Fernandez Mediavilla

Mechanical & Aerospace Engineering Theses & Dissertations

Additive manufacturing (AM) is becoming a robust production technology for aerospace, healthcare, and construction industries among others. Fused Deposition Modelling (FDM) is one of the methods most used to 3D print products. FDM has limitation due to interlayer adhesion and restriction imposed by the printing direction. Specially with AM composites, as reinforced nylon PA6 with short fibers, parts show more strength along the direction of the filament due to the alignment of the carbon fibers, but weaker in other directions. The proposed method to solve this issue is to print parts separately and join them together by fusion bonding. PA6/CF …

Post-Consolidation Process For Modifying Microscale And Mesoscale Parameters Of 3d Printed Composite Materials, Arief Yudhanto, Alwaleed Aldhirgham, Eric Feron, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Advancements in additive manufacturing technology (3D printing) have enabled us to fabricate reasonably good parts using continuous fiber-reinforced matrix composites. Unfortunately, most of these 3D-printed composite parts inherently possess a large number of voids originating from the trapped air within and between molten composite beads during the deposition stage. Removing the voids has thus become a key challenge in attempts to apply 3D printed composite parts for fabricating stiff/strong load-bearing structures. Here, we employed a classical process, viz. compression molding, to post-consolidate 3D-printed continuous carbon fiber-reinforced polyamide (CFPA), and to investigate the implications in terms of microscale parameters (void content) …

Surface Preparation Study, Ryan Ferguson

Williams Honors College, Honors Research Projects

This work explores a custom air atmospheric pressure plasma treatment (APPT) machine’s effectiveness in cleaning and chemically activating a CFRP surface. It is explore by implementing water contact angle (WCA) measurements, water-break free (WBF) testing, and adhesive tubular lap-joint (TLJ) tensile testing. An 8x3 test matrix of different machine parameters is defined with the bounding conditions being the machine’s capabilities and industry standard recommendations. Each configuration of the test matrix is explored after treatment at multiple time intervals up to 2 weeks afterwards to gain insight into the outlife of the treatments with the intention of adhesively bonding to the …

Experimental Characterization Of Additively Manufactured Multi-Feather Wingtip Devices, Patricio Garzon

Doctoral Dissertations and Master's Theses

Soaring birds have evolved to fly for long periods of time without flapping their wings. Inspired by the flight of these birds, the proposed thesis presents an experimental investigation focused on wingtip devices designed based on biomimicry. The overarching engineering objective was to reduce the induced drag as a means to improve the fuel efficiency via these experimental wingtips. An associated secondary objective was to establish a method for manufacturing complex structures suitable for wing tunnel testing. A manufacturing technique that involved using composite weaves to reinforce additively manufactured structures was developed. This technique has the potential to reduce manufacturing …

The Development And Characterization Of Piezoelectric- Magnetostrictive Smart Self-Sensing Composites, George Relebohile Qhonosheane

Mechanical and Aerospace Engineering Dissertations - Archive

The composites industry is expanding due to the growing global demand for high-performance materials. How do you ensure the production of composites is as smooth and effective as possible while maintaining the high quality of the material? The key issues in composites include crack occurrence, sticking to molds in the production process, and durability differences during their operation. However, monitoring such cases can be challenging. The industry is in need of a smart solution to be able to obtain accurate data from the raw material. This work focuses on the development of smart composite materials. The word composite comes from …

Manufacturing Process Considerations When Transitioning From Thermoset To Thermoplastic Composite Material For Urban Air Mobility Propellers, Samuel Leonard Jones Iii

Theses and Dissertations

Aerospace manufacturing has seen continually increased use of carbon fiber reinforced polymers in aircraft structures. The favorable strength to weight ratios, as well as the increased resistance to fatigue and corrosion, compared to metallic structures, provide a common argument for further research and development of composite airframes. Two main classes of carbon fiber reinforced polymers can be distinguished, thermosetting polymers and thermoplastic polymers. Thermoset polymers have been relied on for decades for the ability to reliably produce strong laminates for aircraft structures. By comparison thermoplastic polymers experience less comparable utilization on primary structures despite boasting similar or greater performance capabilities …

Analysis Of After Impact Characteristics And Structural Optimization Of Cfrp Composite Plate, Zhennan He

Doctoral Dissertations and Master's Theses

Low-velocity impact (LVI) on composites may cause Barely Visible Impact Damage (BVID), which is one of the most common damage types and may result in a decrease in strength of the composite. The objectives of this research were (a) to identify the characteristics of a carbon/epoxy composite plate after low-velocity impact, (b) to create a validated model to simulate the impact process and progressive failure, and (c) to perform sizing and shape optimization of the laminate for improving the damage resistance of the plate. As a part of this thesis, composite plates were fabricated using carbon fiber reinforced polymer (CFRP) …

Finite Element Analysis Investigation Of Hybrid Thin-Ply Composites For Improved Performance Of Aerospace Structures, Alana M. Zahn

Mechanical & Aerospace Engineering Theses & Dissertations

Commercial and private aircraft have a need for strong yet light materials in order to have the most ideal performance possible. This study looks at the use of thin-ply composite materials to improve the performance of aircraft structures by means of weight savings and/or strength increase when compared to laminates that are composed of exclusively standard-ply materials. In order to perform an investigation based solely on finite element analysis, validation efforts were performed using test data from open hole tension, open hole compression, notched tension, and notched compression specimens. Once the models were validated sufficiently, the same modeling practices were …

A Multiscale Study Of Cavitation Mechanism And Damage In Soft Materials, Fuad Hasan

Mechanical and Aerospace Engineering Dissertations - Archive

Cavitation is defined as the formation and growth of the gaseous bubble in bulk liquid due to the tensile pressure followed by the violent collapse. The collapse of the bubble is particularly significant due to its potential to cause damage to relatively stronger materials by either creating pressure waves (symmetric collapse) or liquid jet (asymmetric collapse). The study of cavitation in soft materials (e.g., tissue, brain, gelatin gel, etc.) has, therefore, gained a fair share of attention in the scientific communities. Recent studies have indicated that cavitation could be one of the leading causes of the mild Traumatic Brain Injury …