Engineering Commons^™

Effect Of Fiber Proximity On The Pullout Response: A Finite Element Study, Tyler Mitchell

Mechanical Engineering ETDs

With the advancement of computational capabilities, there is growing interest in
developing intricate models for composite materials. This has been historically chal-
lenging due to the multifaceted interactions and failure mechanisms of these materi-
als. Multiscale modeling holds promise for predicting the intricate dynamics of such
materials. A foundational understanding of their microscale behaviors is critical, par-
ticularly the interfacial interactions between the fiber and matrix. This study delves
into the influence of fiber volume fraction (FVF) on fiber pull-out tests, focusing
on the impact of neighboring fibers across different geometries and the underlying
cohesive properties.

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] …

Jcati Carbon Fiber Recycler- Fiber Conveyance, Taylor Miller

All Undergraduate Projects

Sponsored by the Joint Center for Aerospace Technology Innovation (JCATI), this project stems from a partnership between Central Washington University’s Mechanical Engineering Technology program and The Boeing Company. The goal of this partnership was to create a device that repurposes carbon fiber from wing trimmings from the 777. The device features four different students’ projects including the crusher, shredder, oven heating system, and the fiber conveyance system; the focus of this project. The JCATI Carbon Fiber Recycler needed a device to transport material from the shredder to the oven to make for an easier, more seamless production process. To solve …

Effect Of Autoclave Process Parameters On Mechanical Behaviors Of Carbon Fiber Reinforced Polymer Composites Fabricated Via Additive Manufacturing, Quang Hao Nguyen

Honors Undergraduate Theses

Additively manufactured carbon fiber reinforced polymers (CFRP) are vastly studied for their remarkable mechanical properties compared to most other 3D printed materials. Different methods were employed to further increase mechanical performance of CFRP 3D printed parts. The objective of the study is to investigate the effect of autoclave postprocessing on the interlaminar shear behavior between 3D printed CFRP layers. 3D printed CFRP samples were processed with nine combinations of temperature and vacuum in an autoclave. Short beam shear (SBS) tests were performed to characterize the interlaminar shear strength (ILSS) of the samples after autoclave processing. Digital image correlation (DIC) was …

Development Of Alternative Air Filtration Materials And Methods Of Analysis, Ivan Philip Beckman

Theses and Dissertations

Clean air is a global health concern. Each year more than seven million people across the globe perish from breathing poor quality air. Development of high efficiency particulate air (HEPA) filters demonstrate an effort to mitigate dangerous aerosol hazards at the point of production. The nuclear power industry installs HEPA filters as a final line of containment of hazardous particles. Advancement air filtration technology is paramount to achieving global clean air. An exploration of analytical, experimental, computational, and machine learning models is presented in this dissertation to advance the science of air filtration technology. This dissertation studies, develops, and analyzes …

Sensorimotor Content Of Multi-Unit Activity In The Paramedian Lobule Of The Cerebellum, Esma Cetinkaya

Dissertations

Based on Center for Disease Control and Prevention report 2016, around 39.5 million people in the United States suffer from motor disabilities. These disabilities are due to traumatic conditions like traumatic brain injury (TBI), neurological diseases such as amyotrophic lateral sclerosis (ALS), or congenital conditions. One of the approaches for restoring the lost motor function is to extract the volitional information from the central nervous system (CNS) and control a mechanical device that can replace the function of a paralyzed limb through systems called Brain-Computer Interfaces (BCI).

One of the major challenges being faced in BCIs and also in general …

Effect Of Indentation On Sandwich Composite Structure Mechanical Behavior, Marius V. Jatulis

Master's Theses

Composite sandwich structures are prevalent in engineering applications where high strength to weight ratios are critical. A composite sandwich includes the addition of a core material between two composite face sheets to increase ultimate stress in compression and bending loading cases. The performance of many composite sandwich structure configurations is well understood in the undamaged case. This analysis examines a type of damage, low velocity indentation, and determines the effect on mechanical behavior. The scope of the analysis includes manufacturing sandwich composite structures, creating indentation in the composite, and testing the sandwich composite structure. The mechanical behavior of the composite …

Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott

Theses and Dissertations

Carbon Fiber (CF) has different tensile strengths and transverse moduli depending on how they are fabricated. Some CF is export controlled as it can be used for weapons, spacecraft, or gas centrifuges for enriching nuclear fuel. This research project explored a new way to prepare micron sized single CF threads to measure their transverse modulus and compare the moduli of non-export controlled CF to that of an export controlled CF. Five total polyacrylonitrile (PAN) fibers were used in this project, one of which was an export controlled fiber.

Jcati Carbon Fiber Recycler: Oven Enclosure, Margarita Romero

All Undergraduate Projects

Central Washington University partners with Boeing and is funded by the Joint Center of Aerospace Technology Innovation (JCATI) to develop a mechanism that takes carbon fiber wing trimmings from Boeing that are resin coated and recycles carbon fiber. This is done by crushing the wing trimmings and then putting it into a 500°C oven to melt off the resin. This project focuses on the enclosure for the oven and making sure precautions are met such as having the outside surface be less than 45c through heat transfer analysis, argon fills enclosure in 13 minutes through fluid dynamics analysis, and 99% …

Precision Machining Of Polymer Matrix Composites, Victor Martinez Polanco

All Graduate Theses, Dissertations, and Other Capstone Projects

This experiment was started to figure how the precision machining of polymer matrix composites differ from metals such as aluminum and steel. Polymer matrix composites are highly used in powered vehicles for their strength and light weight properties, but they are typically not machined to their final product how metals are. Polymer matrix composites are typically manufactured near their final shape, with some trimming involved to complete its shape. This research machined carbon fiber manufactured through a wet layup and through resin infusion, as well as aluminum and steel to compare their machineability and their surface finish. These materials were …

The Effect Of Shot Dependency On Composite Materials Subject To Ballistic Testing, Clayton C. Hankins

Theses and Dissertations

Ballistic analysis was performed on four common composite armor materials: 3k standard modulus plain weave carbon fiber, 8HS satin weave S-glass fiber, plain weave Kevlar® KM2 600 Denier fiber, and Spectra Shield® 4232 ultra-high molecular weight polyethylene to determine shot dependency based upon shot-to-shot impact distance, degree of penetration from the initial impacts, and the delamination effects from the initial impact. The primary measure of ballistic performance was the projectile velocity which represents a 50% probability of penetration, V₅₀. This velocity was determined using a three-phase optimal design test method with an average of twelve shots per test. …

Composite Pegboard, Asa J. Cusick, Luis Corrales, Joelle Hylton, Wyatt Pauley

Mechanical Engineering

Many of those with mobility limitations who are told they will need a wheelchair for the rest of their lives can actually begin to stand and walk again given the proper tools and support. The current design for a wheelchair seeking to support this process is overly complex, heavy, and exhibits some features that could potentially pose a serious health hazard to those using it. The scope of this project is to aid in the design of an adaptable composite wheelchair frame that can be both lightweight and strong, while still allowing for physical diversity of potential users. Through research …

Error Reduction For The Determination Of Transverse Moduli Of Single-Strand Carbon Fibers Via Atomic Force Microscopy, Joshua D. Frey

Theses and Dissertations

The transverse modulus of single strand carbon fibers is measured using PeakForce Atomic Force Microscopy - Quantitative Nanomechanical Measurement to less than 5 percent error for 11 types of carbon fiber with longitudinal moduli between 924-231 GPA, including export-controlled fibers. Statistical methods are employed to improve the quality of data to exclude outliers within an measurement and within the sample set. A positive linear correlation between the longitudinal and transverse modulus with an R²=0.76 is found. Pitch-based fibers exhibit lower measurement error than PAN-based fibers, while PAN fibers exhibited no apparent modulus correlation when the Pitch fibers are …

Sae Formula Team Carbon Fiber Seat, Jacob Jaksic

Williams Honors College, Honors Research Projects

roject is for the Formula SAE Zips Racing team here at the University of Akron. The team includes Jacob Jaksic, Sean Turner, Dovydas Sodys, Mike White, and Sevin Johnson. We are tasked with reducing the weight of their current seat, while remaining comfortable to the driver. Our plan was to do this with a lightweight material, specifically carbon fiber. Many different steps were required when outlining this project: finalizing a design with verification from our Zips racing advisor, completing FEA analysis on finished design, acquiring material to be molded into seat, and finding a company to fabricate out of carbon …

Sae Formula Team Carbon Fiber Seat, Sean Turner, Jacob Jaksic

Williams Honors College, Honors Research Projects

This project is for the Formula SAE Zips Racing team here at the University of Akron. The team includes Jacob Jaksic, Sean Turner, Dovydas Sodys, Mike White, and Sevin Johnson. We are tasked with reducing the weight of their current seat, while remaining comfortable to the driver. Our plan was to do this with a lightweight material, specifically carbon fiber. Many different steps were required when outlining this project: finalizing a design with verification from our Zips racing advisor, completing FEA analysis on finished design, acquiring material to be molded into seat, and finding a company to fabricate out of …

Discontinuous Recycled And Repurposed Carbon Fiber Reinforced Thermoplastic Organosheet Composites, Philip R. Barnett

Doctoral Dissertations

There is a significant need for low cost, high volume composites in the automotive industry to aid in vehicle lightweighting and safety. The current state-of-the-art severely compromises the mechanical properties of composites to achieve cost and cycle time goals. In this dissertation, a novel composite format, termed discontinuous carbon fiber organosheets, using recycled and repurposed carbon fibers in a thermoplastic matrix is developed and studied. Unlike traditional composites, the long fiber length and rapid processing time yield mechanical properties and cycle times competitive with automotive metals.

Several studies were performed to characterize this new material format. First, samples were manufactured …

Composite Liftwalker For Shurouq, Daniel Martinez, Robert Boyd, Vikram Thridandam, Madeline Faase

Mechanical Engineering

The following document describes the scope of our project and the methods we have deployed in designing and manufacturing a personalized composite LiftWalker for a young woman in Egypt named Shurouq. Our objective is to design a lightweight and durable LiftWalker to improve upon the current product of our project sponsor, Charlie Gutierrez. To accommodate Shurouq’s physical disabilities as well as the limits of transporting the device to her by plane, our team will need to alter the current product’s dimensions, materials, and structure. Through researching similar products and interviewing potential customers, we have compiled engineering specifications to guide the …

Development Of Multi-Axial Fatigue Retrofits For Lock Gate Components, Logan Verkamp

Graduate Theses and Dissertations

Lock gates are essential infrastructure components to the United State (US) supply chain. They create large cost savings and environmental benefits when compared with traditional methods of transport (freight and rail). Because of the large quantity of goods and dependence on these shipping chains, the US economy can be drastically affected by an unexpected gate closure. Unfortunately, many lock gates within the US have reached or exceeded their designed life. Due to the intensity of cyclic loads and the environment, fatigue cracks have become a prominent issue. Developed cracks near the pintle region (a joint which the gate rotates and …

The Manufacturing And Characterization Of Pseudo-Woven Carbon Fiber Composite Architectures For Enhanced Damage Tolerance, Cyrus Vakili Rad

Theses and Dissertations

Traditional unidirectional carbon fiber reinforced polymer matrix composites exhibit brittle failure, limited toughness, and poor damage tolerance often resulting in the overdesign of composite systems. This work focuses on the automated fiber placement (AFP) manufacturing and characterization of a new family of pseudo-woven (PW) laminate architectures aimed to enhance impact resistance and damage tolerance. The PW laminate architecture uses a specialized in situ AFP process implementing tow skips to produce its laminate architecture. This results in a heterogeneous architecture possessing spatially variable in-plane material properties unlike traditional laminated composites. This heterogeneity is associated with topological variations in the fiber orientations …

A Post-Impact Behavior Of Platelet-Based Composites Produced By Compression Molding, Christopher Eugene Ervin Volle

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg-based Platelet Molded Compounds (PPMCs) are quickly becoming a widely used method for creating structural components in the aerospace and automotive industries. The discontinuous nature of the platelets used allow good formability of both complex and basic structural components; from seats on commercial airplanes to outer panels of vehicles.

This thesis will look at an important research question of these composites: how PPMCs behave under dynamic loading, e.g. impact and post-impact behavior. Impact is analyzed using recorded force and velocity data to find the absorbed energy. Digital image correlation is used with compression after impact testing to study the propagation …

Through-Thickness Reinforcement And Repair Of Carbon Fiber Based Honeycomb Structures Under Flexure And Tension Of Adhesively Bonded Joints, Aleric Alden Sanders

Mechanical & Aerospace Engineering Theses & Dissertations

Repair and reinforcement of composite honeycomb structures is an area of concern as higher demands are being placed on high strength, lightweight structural materials, such as carbon fiber reinforced plastics and corresponding honeycomb structures. A common issue with these structures is when a delamination in the facesheet may form and spread, leading to a failure scenario. An investigation of adding a through thickness reinforcement (TTR) to these structures at the sample level that undergo four-point-bending, tension, and joining methods is conducted throughout this thesis. The embedding of pultruded carbon fiber rods is found to be an ideal addition to composite …

Low Weight Design Of A Pressure-Fed System For A Small Payload Launch Vehicle, Lucero Buendia

Open Access Theses & Dissertations

Carbon fiber reinforced polymer (CFRP) composites have become of great interests to aerospace industries because of their low-cost, lightweight and their tailorable mechanical properties. In aerospace structures, for example, heavy metals have been used in cryogenic fuel and oxidizer tanks for over 50 years. However, weight savings can be substantial if materials such as composites are used instead. From Delta IV heavy-lift launch vehicle it is known that cryogenic composite tanks can save approximately up to 30% of weight in fuel and oxidizer tanks. Although there is a wealth of studies in the mechanical behavior of composites at room temperature, …

Additively Manufactured Continuous Carbon Fiber Thermoplastic Composites For High-Performance Applications, Nekoda Van De Werken

Mechanical Engineering ETDs

The goal of this dissertation is to provide a foundation for the advancement of additive manufacturing (AM) toward production of high-performance carbon fiber reinforced polymer matrix composites (CFRPs). AM can provide valuable advantages over conventional composite manufacturing techniques, including the control over fiber orientation, capability of manufacturing complex geometries, out-of-autoclave processing, elimination of the need for composite tooling, and the ability to perform lights-out manufacturing. Currently, however, a suite of challenges related to modelling, design, manufacturing defects, and general limitations in the current understanding of the processing-structure-property relationships exist in AM of composites. To this end, this dissertation investigates novel …

Effects Of Bio-Composites In Corrugated Sandwich Panels Under Edgewise Compression Loading, Jalen Christopher Mano

Master's Theses

Present day composite sandwich panels provide incredible strength. Their largest problem, however, is early bonding failure between the core and the skin. This is due to the low bonding surface area of present cores like honeycomb. Corrugated structures could provide a remedy for this with their much larger bonding surface area. Corrugated structures have extreme mechanical properties deeming them particularly useful in aerospace and automotive applications. However, previous research has shown that the stiffness of carbon fiber causes debonding and drastic failure when used as both a core and a skin. Bio-composites have properties that could strengthen the corrugated sandwich …

Strength Investigation Of Damaged And Repaired Thin-Walled Composite Structures, Analise Barlow

Theses and Dissertations

The purpose of this research was to quantify the strength of novel composite repair methods for thin-walled composite structures. Carbon/epoxy plates were manufactured and repairs were made at Gloyer-Taylor Laboratories. At BYU, specimens were damaged in a controlled and repeatable process. Three damage modes were implemented: impact, groove, and abrasive damage. Tensile strength tests were performed on control, damaged, and repaired specimens. Four 24 x 24 in (60 x 60 cm) carbon/epoxy plates were received. Each plate was made up of seven plies cured together with epoxy resin for a nominal total thickness of 0.04 in (1.02 mm). The thickness, …

Reinventing The Wheel, Esther K. Unti, Ahmed Z. Shorab, Patrick B. Kragen, Adam M. Menashe

Mechanical Engineering

Reinventing the Wheel selected tires and designed wheels for the 2018 Cal Poly, San Luis Obispo Formula SAE combustion vehicle. Available tire options were evaluated for steady-state and transient performance as well as vehicle integration. A single-piece composite wheel with hollow spokes was designed to meet stiffness, strength, and tolerance requirements. A detailed study of wheel loading and geometric structural efficiency was performed. Finite element analysis was used to iterate the geometry and laminate. A two-piece male mold was designed and machined to manufacture the wheel. Removable silicone inserts were used to create the hollow spokes.

Effect Of Aerogel On The Thermal Performance Of Corrugated Composite Sandwich Structures, Jacob Dillon Chess

Master's Theses

Current insulation solutions across multiple industries, especially the commercial sector, can be bulky and ineffective when considering their volume. Aerogels are excellent insulators, exhibiting low thermal conductivities and low densities with a porosity of around 95%. Such characteristics make aerogels effective in decreasing conductive heat transfer within a solid. These requirements are crucial for aerospace and spaceflight applications, where sensitive components exist among extreme temperature environments. When implemented into insulation applications, aerogel can perform better than existing technology while using less material, which limits the amount of volume allocated for insulation. The application of these materials into composites can result …

Permeability Characterization And Fluorescent Void Flow Monitoring For Processing Simulation, John Caleb Lystrup

Theses and Dissertations

Liquid composite molding (LCM) is growing in importance alternative to traditional prepreg-autoclave methods for manufacture aerospace composites. The most significant roadblock to industry's implementation of LCM is the optimization of resin flow to ensure high quality parts. This study developed process optimization tools to foster the adaptation of LCM. The following dissertation characterized the permeability of reinforcement fabrics under various processing conditions, and investigated in-situ bubble flow with carbon fiber. The purpose of this research is to extend the understanding of LCM and push forward the state of the art via sub-studies captured in five chapters, or manuscripts. Research from …

Effects Of Automated Fiber Placement On High Strain Rate Compressive Response Of Advanced Composites, Alexander Trochez

Mechanical & Aerospace Engineering Theses & Dissertations

Automated Fiber Placement (AFP) technology shows great promise in manufacturing carbon fiber composite structures. However, intermittent defects occur in the process that can affect the overall mechanical performance of the structure. The aim of this work is to investigate the effects of deliberately placed principal defects (Gap, Overlap, and Fold) on the compressive response under quasistatic (strain rate ~10^-3 s^-1) and dynamic (strain rate ~10³ s-1) loading conditions. The controlled defects were placed at the laminate level in different orientations and depths. High strain rate compression experiments were conducted using a split Hopkinson pressure bar (SHPB) …

Prove Endurance Car Front Suspension, Lauren A. Williams, Logan Simon, Justine G. Kwan

Mechanical Engineering

This document details the collaborative Mechanical Engineering Senior Project with Cal Poly PROVE Lab on PROVE Lab’s Project 2; an electric vehicle designed to travel 1000 miles on a single charge. Logan Simon, Justine Kwan, and Lauren Williams are given the challenge of designing an innovative proof of concept front suspension suspension for this vehicle.

After detailed research of new suspension systems, it was determined that the innovative nature could be in the form of unique manufacturing methods, materials use, or mechanical design. At this point in time, this vehicle is a purely conceptual design with no concrete requirements. Therefore …