Mechanical Engineering Commons^™

An Experimental Analysis Of Thin Sheet Metal Bending By Ultrafast Laser Peen Forming, Bryce J. Tessmann

All Theses

This study demonstrates the viability of femtosecond laser peen forming for bidirectional sheet metal bending. Ultrafast laser forming is a valuable method thanks to its flexibility, negation of springback, no need for a confining or protective layer, and minimalization of thermal degradation in comparison to other forming processes. However, femtosecond lasers have traditionally been believed to be unsuitable for laser forming in comparison to nanosecond lasers, particularly bidirectional bending, because the induced shock waves were expected to be weak. Conversely, in this study it is elucidated that the femtosecond laser-induced shock waves are extremely strong (several hundred GPa) but the …

Examining The Different Snap-Through Characteristics Of Bistable Cfrp Composite Laminates, Vishrut Deshpande

All Theses

Bistable carbon fiber composites, whose bistability arises from having asymmetric fiber layouts in different layers, have shown immense potential for use in shape morphing and adaptive structure applications. While many studies in this field focus on these composite laminates’ external shapes at the two stable states, their snap-through behavior of shifting from one stable shape to the other remains a critical aspect to be investigated in complete detail. Moreover, symmetric loading conditions have been extensively studied based on the classical lamination theory, but the asymmetric loading conditions received far less attention. Therefore, this study examines an asymmetric, localized point load …

Investigating The Effects Of Topology On The Fracture And Failure Mechanisms Of Low Density Metamaterials, Kaitlynn Melissa Conway

All Dissertations

Advances in additive manufacturing have enabled the creation of low density metamaterials with fine features and complex topographies. These new metamaterial topologies and size scales not previously possible broaden the spectrum of lightweight materials with unique properties that are advantageous in a variety of applications. There however is a lack of understanding of metamaterial failure and fracture behaviors. Studies tend to report only a few material properties rather than a comprehensive description of behavior. Due to this, there is a hesitancy to incorporate metamaterials into engineering designs despite proven remarkable properties. This work seeks to investigate in three parts the …

Characterization Of Friction Element Welding Using Finite Element Modeling, Ankit Varma

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Friction element welding (FEW) has been advocated as a solution to weld different materials together, with the ability to join high-strength materials for a range of thicknesses with low input energy and a short processing time. This work develops a coupled thermal-mechanical finite element model to better understand the physical mechanisms involved in the process and to predict temperature and material flow during the process. Furthermore, microstructural analysis is performed for the steel layer using a scanning electron microscope and Vickers microhardness tester to understand the variation in its grain structure and hardness. Results from the finite element model and …

Control, Decision-Making, And Learning Approaches For Connected And Autonomous Driving Systems With Humans-In-The-Loop, Fangjian Li

All Dissertations

By virtue of vehicular connectivity and automation, the vehicle becomes increasingly intelligent and self-driving capable. However, no matter what automation level the vehicle can achieve, humans will still be in the loop despite their roles. First, considering the manual driving car as a disturbance to the connected and autonomous vehicles (CAVs), a novel string stability is proposed for mixed traffic platoons consisting of both autonomous and manual driving cars to guarantee acceptable motion fluctuation and platoon safety. Furthermore, humans are naturally considered as the rider in the passenger vehicle. A human-centered cooperative adaptive cruise control (CACC) is designed to improve …

Development And Application Of 3d Kinematic Methodologies For Biomechanical Modelling In Adaptive Sports And Rehabilitation, Anne Marie Severyn

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Biomechanical analysis is widely used to assess human movement sciences, specifically using three-dimensional motion capture modelling. There are unprecedented opportunities to increase quantitative knowledge of rehabilitation and recreation for disadvantaged population groups. Specifically, 3D models and movement profiles for human gait analysis were generated with emphasis on post-stroke patients, with direct model translation to analyze equivalent measurements while horseback riding in use of the alternative form of rehabilitation, equine assisted activities and therapies (EAAT) or hippotherapy (HPOT). Significant improvements in gait symmetry and velocity were found within an inpatient rehabilitation setting for patients following a stroke, and the developed movement …

Predictive Performance And Teaming Via The Mist-C Ocean Hierarchy Utilizing Personality And Skills, Brighton H. Owen

All Theses

This thesis seeks to establish and define the individual, the team as an entity, and qualify various metrics to predict team performance. When several individuals come together, they form a team that is often capable of designing and developing concepts beyond the individual on their own by methods of task dispersion, goal orientation, communication, and more. With these teams comes growth and increased performance leading to more efficient processes and better metrics by which performance may be measured. To achieve this, 34 engineering students in the AerosPACE senior design program, which lasted two semesters, were asked to complete surveys in …

Analysis Of The Self-Heating Effect On Unfilled Poly(Methyl Methacrylate) Due To Cyclic Behavior, Muhammed R. Kose

All Theses

Poly(methyl methacrylate, (PMMA) has been implemented as part of the supporting structure in complete hip and knee replacements since the 1950s. Known as bone cement while in the body, PMMA is known to undergo compressive and tensile stresses that wear down the bio-compatible barrier and cause pieces to come loose inside the human body. These pieces are then attacked by the body’s own nervous system, leading to inflammation, and eventually necessitating replacement. It has been documented that under cyclic loading PMMA can reach temperatures that start to degrade its tensile capabilities. In this study the potential cause of self-heating was …

A Study On Effect Of Manufacturing Parameters On Morphology Of A356 Aluminum Foam, Nikhil Nanabhau Mahajan

All Theses

Metal foams have shown an excellent promise for usage as multifunctional material concerning research & development in the last 20 years. They provide remarkable mechanical as well as physical properties being lightweight. Open-cell metal foams have already been used in sound and noise absorption. Open-cell metal foams are outstanding for use in heat exchangers, filters, and many more applications, while closed-cell foams show excellent characteristics in impact energy absorptions. Closed-cell metal foams have higher energy absorption than their solid parent metal as they convert most of the impact energy into deformation energy. Metal foams have been used as prominent safeguard …

Thermoforming Process Effects On Structural Performance Of Carbon Fiber Reinforced Thermoplastic Composite Parts Through A Manufacturing To Response Pathway, Madhura Limaye, Sai Aditya Pradeep, Anmol Kothari, Sushil Savla, Akshat Agha, Srikanth Pilla, Gang Li

Publications

Thermoforming process of thermoplastic-based continuous CFRP's offer a major advantage in reducing cycle times for large-scale productions, but it can also have a significant impact on the structural performance of the parts by inducing undesirable effects. This necessitates the development of an optimal manufacturing process that minimizes the introduction of undesirable factors in the structure and thereby achieves the targeted mechanical performance. This can be done by first establishing a relationship between the manufacturing process and mechanical performance and successively optimizing it to achieve the desired targets. The current study focuses on the former part, where a manufacturing-to-response (MTR) pathway …

Product Lifecycle Management - Application Of Patterning Methods To Gas Turbine Blades And Creation Of Learning Materials, David Procopio

All Theses

To compete in the global marketplace, companies need to embrace virtual design and manufacturing methods. Product Lifecycle Management (PLM) embodies both the workflow processes and tools to bring forth products from conception to design to fabrication to service to decommissioning, and to eventual recycling. In response to the growing demand for engineers and technicians with these critical skills, colleges and universities should introduce these virtual tools through seminars, software workshops, and computer laboratory sessions. Some of the opportunities in the PLM Center at Clemson University include short courses on PLM practices, focused software training sessions, hands-on exploration activities, and research …

Development And Application Of A Digital Twin For Chiller Plant Performance Assessment, Mihir Kale

All Theses

As the complexity of industrial equipment continues to increase, the management of the individual machines and integrated operations becomes difficult without computer tools. The availability of streaming data from manufacturing floors, plant operations, and deployed fleets can be overwhelming to analyze, although it provides opportunities to improve performance. The use of dedicated monitoring systems in the plant and field to troubleshoot machinery can be integrated within a product lifecycle management (PLM) architecture to offer greater features. PLM offers virtual processes and software tools for the design, analysis, monitoring, and support of engineering systems and products. Within this paradigm, a digital …

Design And Fabrication Of A Polymer Fdm Printer Capable Of Build Parameter Monitoring And In-Sit Geometric Monitoring Via Photogrammetry, Travis Roberts

All Theses

Additive manufacturing, or 3D printing, is a complex process that creates free-form geometric objects by sequentially placing material in a location to construct an object, usually as a layer-by-layer process. One of the most widespread methods is Fused Deposition Modeling (FDM). FDM is used in many of the consumer-grade polymer 3D printers available today. While consumer grade machines are cheap and plentiful, they lack many of the features desired in a machine used for research purposes and are often closed-source platforms. Commercial-grade models are more expensive and are also usually closed-source platforms that do not offer flexibility for modifications often …

Mechanical Interfacial Locking And Multiscale Modeling Of Reinforced Thermoplastic Composites For Structural Applications, Anmol Kothari

All Dissertations

The ever-growing pressure of reducing the adverse impact of transportation systems on environment has pushed industries towards fuel-efficient and sustainable solutions. While several approaches have been used to improve fuel efficiency, the light-weighting of structural components has proven broadly effective. In this regard, reinforced thermoplastic composites (RTPC), owing to their high recyclability, higher impact strength and fast cycle times, have become competitive candidates at an industrial scale. However, to implement RTPC toward large scale structural applications several challenges pertaining to material design and manufacturing effects need to be addressed. To this end, a computational study is carried out to address …

Numerical And Experimental Study Of Machining Process Of High Strength Lightweight Materials, Chao Zhang

All Dissertations

No abstract provided.

A Manufacturing-To-Response Pathway For Formed Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye

All Theses

Over the past decade, there has been an increased adoption of thermoplastic and thermoset based continuous carbon fiber reinforced polymer (CFRP) composites for structural applications in several industries. Among the different manufacturing methods, thermoforming process for thermoplastic based continuous CFRP’s offer a major advantage in reducing cycle times for large scale productions. Similarly, out-of-autoclave curing process for thermoset based continuous CFRP’s using heated tooling enables production of large composite structures. However, these manufacturing processes can have a significant impact on the structural performance of parts by inducing undesirable effects. These effects include inhomogeneous fiber orientations, thickness variations, and residual stresses …

Hemodynamic Response To Device Titration In The Shunted Single Ventricle Circulation - A Patient Cohort Modeling Study, Chet Villa, Farha Zafar, Angela Lorts, Ethan Kung

Publications

Clinical outcomes of ventricular assist device (VAD) support for shunted single ventricle patients trail the larger population due in part to the challenges in optimizing VAD support and balancing systemic and pulmonary circulations. We sought to understand the response to VAD titration in the shunted circulation using a lumped-parameter network modeling six patient-specific clinical cases. Hemodynamic data from six patients (mean body surface area = 0.30 m²) with a systemic-to-pulmonary shunt was used to construct simulated cases of heart failure and hemodynamic response to increasing VAD flow from 5 to 10 L/min/m². With increasing VAD flow, …

Design, Development And Temporal Evaluation Of An Mri-Compatible In-Vitro Circulation Model Using A Compliant Aaa Phantom, Mirunalini Thirugnanasambandam, Tejas Canchi, Senol Piskin, Christof Karmonik, Ethan Kung, Prahlad Menon, Stephanie Avril, Ender A. Finol

Publications

Biomechanical characterization of abdominal aortic aneurysms (AAA) has become commonplace in rupture risk assessment studies. However, its translation to the clinic has been greatly limited due to the complexity associated with its tools and their implementation. The unattainability of patient-specific tissue properties leads to the use of generalized population-averaged material models in finite element analyses, which adds a degree of uncertainty to the wall mechanics quantification. In addition, computational fluid dynamics modeling of AAA typically lacks the patient-specific inflow and outflow boundary conditions that should be obtained by non-standard of care clinical imaging. An alternative approach for analyzing AAA flow …

Investigating The Presence Of Culture In Engineering Design: A Case Study On Culture In Design Methods, Perception, And Outcomes, Malena Ataa Durowaah Agyemang

All Dissertations

Overwhelming global statistics on economic, social, and health disparities has driven engineers and designers to develop solutions to minimize these disparities [1,2,11,12,3–10]. For the scope of this study, these efforts are referred to as design for humanitarian engineering and global development (HEGD). HEGD solutions are designed to improve access to medical technologies, energy, clean water, and even spark economic development [1–10]. However, many HEGD solutions go unadopted, halting their intended benefits [9,13,22,23,14–21]. Efforts to improve HEGD adoption have focused on ways to incorporate culture in the design solution’s aesthetics or in approaches post-deployment [24,25,34,35,26–33]. However, a review of failed HEGD …

Photovoltaics- And Battery-Based Power Network As Sustainable Source Of Electric Power, Prahaladh Paniyil, Vishwas Powar, Rajendra Singh, Benjamin Hennigan, Pamela Lule, Matthew Allison, John Kimsey, Anthony Carambia, Dhruval Patel, Daniel Carrillo, Zachary Shriber, Truman Bazer, James Farnum, Kushal Jadhav, Dalton Pumputis

Publications

With the rise in the utilization of free fuel energy sources, namely solar and wind, across the globe, it has become necessary to study and implement models of a sustainable power network. This paper focuses on the design of a conceptual power network based on photovoltaics (PV) for power generation and lithium-ion batteries for storage. The power system showcases the various metrics that are involved in a grid-tied PV- and battery-based power network. It also encompasses the various design parameters and sizing considerations to design and conceptualize such a power network. The model focuses on the importance of the conservation …

Static Pressure Recovery Effects Of Conical Diffusers With Swirling Inlet Flow, James Ray Wright Iii

All Theses

Conical diffusers are used in hundreds of engineering applications in various industries. Some of the operating conditions that they operate under cause swirling flow to enter the diffuser. It is generally well documented that the addition of swirl to the flow of a diffuser allows for greater divergence angles without wall separation, resulting in better overall performance of the diffuser and the machine it’s attached to. It is also known that as swirl strength is increased, the flow will eventually breakdown, resulting in internal flow recirculation and decreased diffuser performance. However, the relationship between the diffuser geometry and its performance …

Delineating The Relationship Between Cardiovascular Physiology And Subject Characteristics Using Computational Modeling And Systemic Review, Aseem Pradhan

All Theses

Lumped Parameter Networks (LPN) are computational models that can capture the systemic responses of the cardiovascular system. An LPN describes the systemic behavior by providing outputs such as the blood pressure, flowrate, and heart chamber volume at the points defined in the network. To use the LPN for medical applications, it needs to provide output values that represent the physiology of realistic subjects. The cardiovascular system exhibits short-term and long-term adaptations to factors such as aging, weight gain, exercise, etc. Therefore, subject characteristics such as age, height, weight, etc. affect the output values of the LPN. Current literature reports the …

A Model For Simulation Of Convective Heat Assisted Single Point Incremental Forming Of Thermoplastics, Shubhamkar Kulkarni

All Dissertations

The overarching objective of this research is to develop a finite element model for simulation of the single point incremental forming (SPIF) process at different temperatures including convective heat assisted SPIF (CHASPIF). Single point incremental forming (SPIF) is a flexible manufacturing process with low tooling costs and times compared to thermoforming and die forming, for low production volumes. Convective heat assisted single point incremental forming (CHASPIF) is a variant of the SPIF process in which an external hot air source is used to heat the region surrounding the tool to improve formability, which can be assessed either in terms of …

Predictive Models For Pulmonary Artery Size In Fontan Patients, Akash Gupta, Chris Gillett, Patrick Gerard, Michael M.H. Cheung, Jonathan P. Mynard, Ethan Kung

Publications

We developed models of pulmonary artery (PA) size in Fontan patients as a function of age and body surface area (BSA) using linear regression and breakpoint analyses based on data from 43 Fontan patients divided into two groups: the extracardiac conduit (ECC) group (n = 24) and the non-ECC group (n = 19). Model predictions were compared against those of a non-Fontan control group (n = 18) and published literature. We observed strong positive correlations of the mean PA diameter with BSA (r = 0.9, p < 0.05) and age (r = 0.88, p < 0.05) in the ECC group. The absolute percentage differences between our BSA and age model predictions against published literature were less than 16% and 20%, respectively. Predicted PA size for Fontan patients was consistently smaller than the control group. These models may serve as useful references for clinicians and be utilized to construct 3D anatomic models that correspond to patient body size or age.

A Protocol For Automated A Posteriori Adaptive Meshing With Simvascular: A Test Case, Akash Gupta, Ethan Kung

Publications

Objective

Operational details regarding the use of the adaptive meshing (AM) algorithm available in the SimVascular package are scarce despite its application in several studies. Lacking these details, novice users of the AM algorithm may experience undesirable outcomes post-adaptation such as increases in mesh error metrics, unpredictable increases in mesh size, and losses in geometric fidelity. Here we present a test case using our proposed iterative protocol that will help prevent these undesirable outcomes and enhance the utility of the AM algorithm. We present three trials (conservative, moderate, and aggressive settings) applied to a scenario modelling a Fontan junction with …

A Survey Of Mathematical Models Of Human Performance Using Power And Energy, Vijay Sarthy Mysore Sreedhara, Gregory M. Mocko, Randolph E. Hutchison

Publications

The ability to predict the systematic decrease of power during physical exertion gives valuable insights into health, performance, and injury. This review surveys the research of power-based models of fatigue and recovery within the area of human performance. Upon a thorough review of available literature, it is observed that the two-parameter critical power model is most popular due to its simplicity. This two-parameter model is a hyperbolic relationship between power and time with critical power as the power-asymptote and the curvature constant denoted by W′. Critical power (CP) is a theoretical power output that can be sustained indefinitely by …

Cavopulmonary Support For Failing Fontan Patients: Computational And In Vitro Assessment, Masoud Farahmand

All Dissertations

Congenital heart defects are responsible for the mortality of approximately 300,000 newborn each year. One study in 2010 estimated that over 2 million patients were living with congenital heart defects in the United States. Congenital heart defects have the highest hospitalization cost among other birth defect categories. The damage on the U.S economy in 2013 was estimated $6.1 billion. The most complex and severe form of these defects results in single ventricle physiology. Fortunately, over the last 50 years, these patients have been able to survive into adulthood as a result of three stages of surgeries culminating with Fontan operation. …

Factors Affecting Cardiovascular Physiology In Cardiothoracic Surgery: Implications For Lumped-Parameter Modeling, Joshua Kaufmann, Ethan Kung

Publications

Cardiothoracic surgeries are complex procedures during which the patient cardiovascular physiology is constantly changing due to various factors. Physiological changes begin with the induction of anesthesia, whose effects remain active into the postoperative period. Depending on the surgery, patients may require the use of cardiopulmonary bypass and cardioplegia, both of which affect postoperative physiology such as cardiac index and vascular resistance. Complications may arise due to adverse reactions to the surgery, causing hemodynamic instability. In response, fluid resuscitation and/or vasoactive agents with varying effects may be used in the intraoperative or postoperative periods to improve patient hemodynamics. These factors have …

Factors Affecting Cardiovascular Physiology In Cardiothoracic Surgery: Implications For Lumped-Parameter Modeling, Joshua Kaufmann, Ethan Kung

Publications

Cardiothoracic surgeries are complex procedures during which the patient cardiovascular physiology is constantly changing due to various factors. Physiological changes begin with the induction of anesthesia, whose effects remain active into the postoperative period. Depending on the surgery, patients may require the use of cardiopulmonary bypass and cardioplegia, both of which affect postoperative physiology such as cardiac index and vascular resistance. Complications may arise due to adverse reactions to the surgery, causing hemodynamic instability. In response, fluid resuscitation and/or vasoactive agents with varying effects may be used in the intraoperative or postoperative periods to improve patient hemodynamics. These factors have …

The Influence Of Incorporation Of Mn On The Pitting Corrosion Performance Of Crfeconi High Entropy Alloy At Different Temperatures, H. Torbati-Sarraf, Mitra Shabani, Paul D. Jablonski, Garrett J. Pataky, A. Poursaee

Publications

The electrochemical behavior and susceptibility to pitting corrosion of CrFeCoNi and CrMnFeCoNi high entropy alloys were studied in a 0.1 M NaCl solution at temperatures ranging from 25 to 75 °C. Electrochemical measurements revealed that CrMnFeCoNi is more susceptible to oxide film breakdown and localized corrosion compared to CrFeCoNi. Post corrosion microscopic observations showed severe pitting corrosion for CrMnFeCoNi in higher temperatures compared to CrFeCoNi. Based on in-depth XPS profile measurements on the remaining oxide films, this behavior was attributed to the depletion of Cr in the oxide film and detrimental presence of Mn in the matrix solid solution of …