Aerospace Engineering Commons^™

Development Of A Model For Fire Spread In Low-Gravity Conditions, Kathleen Martinus

The Journal of Purdue Undergraduate Research

No abstract provided.

Predictive Maintenance Analysis Of Turbofan Engine Sensor Data, Stanley A. Melkumian

The Journal of Purdue Undergraduate Research

Predictive maintenance in aviation and aerospace applications is among the most explored problems in machine learning (ML) and artificial intelligence (AI), and datasets such as NASA’s C-MAPPS turbofan engine degradation simulation data have proven invaluable, helping researchers explore numerous questions on engine performance, maintenance, and failure. The purpose of this study was to extend the current research on predicting the remaining useful life (RUL) of engines and their risk classification. Starting with simple yet under-investigated nonlinear survival and random forest models, the analysis implemented eXtreme Gradient Boosting (XGBoost) and long short-term memory (LSTM) from TensorFlow’s Keras library. For both regression …

Theory And Algorithms To Learn, Propagate, And Exploit Uncertainty For Stochastic Optimal Control Of Dynamical Systems, Vignesh Sivaramakrishnan

Electrical and Computer Engineering ETDs

Non-Gaussian uncertainty frequently arises in learning and control problems involving stochastic dynamical systems, particularly in autonomous vehicles, UAVs, satellites, and robotics. In this dissertation, we propose a new framework that leverages characteristic functions that provides a frequency-domain representation of random variables. The dissertation is structured into three key areas. First, we address model-based stochastic optimal control for linear systems with non-Gaussian noise, demonstrating that characteristic functions can be used to enforce chance constraints and control systems toward desired distributions. Second, we explore data-driven stochastic control, utilizing empirical characteristic functions to handle systems with unknown disturbances. In addition, we derive several …

Discrete Particle Dynamics Models: Computational Aspects And Applications, Yuxuan Wu

Doctoral Dissertations and Master's Theses

Particle dynamics considers discrete particles as Newtonian point masses in diverse domains such as, pedestrian particles in pedestrian movement modeling and molecules in material science modeling. These dynamic modeling approaches share a commonality in computational approach where a series of ordinary differential equations are solved for the particle’s motion and equilibrium under active interactions and boundary conditions. In general, particle dynamics approaches are computationally intensive and address problems that require a vast parameter design space. In this dissertation, a computational paradigm is developed for large-scale particle dynamics modeling and demonstrated by three process design applications, (a) infection risk modeling for …

Investigation Of Coupled Fluid-Structure Interactions In Supersonic Flows, Seshendra Palakurthy

Theses and Dissertations

The skin panels used in high-speed flights are exposed to various types of loads, such as inertial, elastic, and aerodynamic loads. In addition, oblique shock impingement can cause flow separation and unsteady aerodynamic loading, which can reduce vehicle performance and result in acoustic noise and viscous heating. These loads, when combined, can result in a complex dynamic response, such as flutter. Flutter is characterized by sustained unsteadiness or structural vibrations. Although flutter might not be immediately harmful, it can lead to fatigue failure of the structural components. A vast amount of literature already exists on the panel flutter induced by …

Performance Evaluation Of Routing Protocols And Ml-Based Enhancements For Uav-Assisted Post-Disaster Communication Networks, Prachi Choudhary

Doctoral Dissertations and Master's Theses

During natural disasters, the existing communication systems collapse, and the disaster-affected areas become disconnected without any means of exchanging information. The collapse of existing communication networks poses challenges for First-Responders (FRs) in locating survivors during Search and Rescue (SAR) operations and for survivors to communicate for emergency aid. To alleviate post-disaster consequences and save lives, Uncrewed Air Vehicles (UAVs), commonly known as drones, can be employed to establish adaptable and reliable emergency communication networks. UAVs offer portability and rapid deployment, making them effective in crises. This thesis presents two main contributions: 1) Evaluation and Comparison of Routing Protocol Performance: The …

Data Intensive Method For Processing Defect Detection And Mitigation For Composites, Deepak Kumar

Doctoral Dissertations and Master's Theses

Composite manufacturing without processing defects is a crucial step in satisfying the production, performance, and quality requirements of composite materials in various industries. Autoclave processing enables manufacturing of high-quality composite parts with excellent mechanical properties, whereas additive manufacturing (AM) offers adaptability to complex designs and streamlined processes. However, each method presents unique challenges; despite the benefits, autoclave processes can still result in processing defects, and AM is particularly susceptible to processing anomalies owing to the novelty of the process. Ensuring the quality and reliability of composite manufacturing is essential to fully capitalize on the advantages offered by both techniques. Artificial …

A Novel, Direct Matrix Solver For Supersonic Boundary Element Method Systems, Cory D. Goates, Doug Hunsaker

Mechanical and Aerospace Engineering Faculty Publications

For problems with very fine surface meshes, typically the most time-consuming step of a boundary element method (BEM, also called a panel method) is solving the final linear system of equations. Many have already studied how to efficiently solve the dense, asymmetric systems which arise in elliptic BEMs. However, this has not been studied for a supersonic aerodynamic BEM, for which the governing PDE is hyperbolic. Due to this hyperbolic character, the matrix equation which arises from a supersonic BEM has a large number of identically zero elements. But the resulting linear system of equations is also not sparse in …

Understanding Confusion: A Case Study Of Training A Machine Model To Predict And Interpret Consensus From Volunteer Labels, Ramanakumar Sankar, Kameswara Mantha, Cooper Nesmith, Lucy Fortson, Shawn R. Brueshaber, Candice Hansen-Koharcheck, Glenn Orton

Michigan Tech Publications

Citizen science has become a valuable and reliable method for interpreting and processing big datasets, and is vital in the era of ever-growing data volumes. However, there are inherent difficulties in the generating labels from citizen scientists, due to the inherent variability between the members of the crowd, leading to variability in the results. Sometimes, this is useful — such as with serendipitous discoveries, which corresponds to rare/unknown classes in the data — but it might also be due to ambiguity between classes. The primary issue is then to distinguish between the intrinsic variability in the dataset and the uncertainty …

Mae Enewsbrief July-Sept 2024, Department Of Mechanical And Aerospce Engineering, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Microstructured Microstructure: Effects Of Concentration Variations On Shock Initiation Of Hmx-Based Plastic Explosives, Dana D. Dlott, Lawrence Salvati, Siva Kumar Valluri

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We studied shock-compressed plastic-bonded explosives (PBX) consisting of HMX (cyclotetramethylene-tetranitramine) with PDMS (poly-dimethylsiloxane) binder, where we varied the HMX weight percent (wt%) up to a maximum of 60 wt%. In this lower-concentration regime, HMX particle clustering causes the PBX structure to consist of HMX clusters and PDMS islands. Structural analysis by optical microscopy allowed us to compute a radial correlation function that gives the mean distance from an average HMX particle to the nearest polymer island. Short-duration 20 GPa shocks (4 ns) created hot spots, and time-resolved thermal emission was used to obtain the growth rate of the subsequent deflagration. …

Accelerating Shock-Driven Reactions In Metal Nanocomposites, Siva Kumar Valluri, Edward L. Dreizin, Dana D. Dlott

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Metal powders are sought as energetic additives to conventional explosives. However, due to their sluggish reaction kinetics with external gaseous oxidizers, pure metals are replaced with metallic composites with intimately mixed condensed phase oxidizers prepared by arrested reactive milling (ARM). Such composites can be initiated by non-thermal, mechanical means; through shear mixing of fuel and oxidizer under a shock compressive load. Since the ARM preparatory technique allows for tuning multiple powder attributes such as fuel/oxidizer of interest, their degree of mixing, amount of oxidizer, particle porosity, among others, a parametric study is crucial in identifying suitable traits for fast reactions …

Hyperspectral Imaging For Temperature Measurements Of Hot Spots In Shocked Plastic-Bonded Explosives, Dhanalakshmi Sellan, Siva Kumar Valluri, Dana D. Dlott

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Hot spots are formed when energetic microstructures are shocked, and they play a critical role in shock sensitivity. It is important to know both the time-dependent size and temperature of the hot spots, in order to generate a kinetic model to describe reaction growth in plastic-bonded explosives (PBX). Here we use a recently developed technique where PBX is fabricated in the form of a thin wafer, embedded within a transparent polymer binder, and shocked with a laser-launched flyer plate that produces pressures of about 30 GPa range. In this method, every crystal of the cyclotetramethylene-tetranitramine (HMX)-based PBX can be observed …

Air Supremacy, The Enabler Of Close Air Support Operations – An Evaluation Of Past, Present, And Future Air Campaigns., Owen Topolnicki

Senior Honors Theses

The achievement of gaining aerial supremacy, or lack thereof, is the hinge upon which Close Air Support (CAS) swings. The attainment of it enables CAS specialist aircraft, not unlike the Ju-87 Stuka or A-10 Thunderbolt II, to be exceptionally effective in their operating environment. While the lack of it, forces aircrews to pioneer new solutions either in the form of multi-role aircraft (capable of self-defense), or other innovative solutions similar to unmanned aerial systems (UAS’s), as aptly seen in the ongoing Russo-Ukrainian conflict. Thus, the ability of an air force to gain air supremacy and to do so quickly, …

Ai, American Politics, And Modern Warfare, Madisen Campbell

Space and Defense

As artificial intelligence (AI) transforms modern warfare, it will pose profound ethical challenges for America’s constitutional democracy.

Technological advancements in the world today, particularly the field of artificial intelligence (AI), impact the current political system in the United States. The importance of understanding and addressing the complex challenges and opportunities of incorporating AI into American politics is key to developing a profound understanding of AI in modern warfare and the implications it has for policy making in America. The need for policy makers and military leaders to receive insight on the development of AI and to develop strategic approaches for …

U.S. 5g Technology Policy: Competition Or Boycott?, Wes Ferguson, Kyle Vargus

Space and Defense

Rather than corral allies and partners across the globe into boycotting Chinese 5G telecommunication systems, U.S. officials should embrace free-and-fair trade competition against China, even in products and services where China may enjoy a technological lead.

The race for technological supremacy has emerged as a defining characteristic of the newest era of great power competition. China and the United States compete to become the dominant world power. Each side is racing to create the latest and most elite technologies to catapult themselves into the lead and give them the edge over their adversary. The fifth generation of wireless technology, called …

Atomic Assurance: Funding A Modern U.S. Test Readiness Program, Mark Tang

Space and Defense

To address intensified strategic competition with Russia and China, the United States should reinstate funding for a modern nuclear Test Readiness Program.

The U.S. has never faced the threat of two adversarial powers with nuclear arsenals that equal our own. With the emphasis on great power competition and mounting aggression by both China and Russia, the risk of conflict with either or both powers is growing. Currently, the U.S. is ill prepared for the possible existential challenge that is deterring conflict with two major nuclear peer adversaries. America’s defense strategy and approach towards the international order must change to protect …

Earth To Orbit: Three Models For Strengthening Space Deterrence, Anton Dahm

Space and Defense

Nuclear, cyber, and integrated deterrence models hold lessons for space deterrence strategy, including declared thresholds, resilient space architecture, and the embrace of international competition in technological innovation.

The United States depends heavily on space capabilities, significantly more than any other country. Not only does space enable navigation, communications, environmental monitoring, and other vital capabilities, but space has also been described as the most essential warfighting domain. However, the U.S. space architecture mirrors its early days: relying on important, expensive payloads on a limited number of satellites. While providing important capabilities to U.S. decision-makers, kinetic and non-kinetic weapons can easily target …

The German Zeitenwende: Turning Point Or Blind Alley?, Savannah Hollen

Space and Defense

The Zeitenwende, or turning point, announced by Chancellor Olaf Scholz after Russia’s invasion of Ukraine in February 2022, may end up leaving Germany with few good defense policy options.

After Russia’s invasion of Ukraine in 2022, Germany vowed to change course, to expand and modernize its military, which for decades has been weak relative to the size of Europe’s leading economy. As bold as Germany’s declarations have been, German leaders may well have walked into a blind alley, unsure of exactly how Zeitenwende will happen, what the final results will be, or the consequences if they never come close to …

Strategic Space Cooperation: U.S. Space Command And The National Guard’S State Partnership Program, David Moore, Jesse Morehouse, Patrick Mitchell

Space and Defense

In 2022, the U.S. Space Command (USSPACECOM) and the National Guard's State Partnership Program (SPP) began pursuing security cooperation objectives while integrating the space domain into greater deterrence efforts. As the newest combatant command (CCMD) with space as its Area of Responsibility (AOR), USSPACECOM has global strategic partnership interests and recognizes the value of the enduring relationships inherent in SPP. This cooperation allows the National Guard to offer its strong relationships, space expertise, and industry knowledge to USSPACECOM. This provides a foundation for USSPACECOM's security cooperation efforts. This article discusses the SPP's role in supporting USSPACECOM's engagement strategy and the …

Arms Control Optimism And Great Power Competition, Damon Coletta

Space and Defense

In its unjust war, Russia rakes at Ukrainian civilian targets using dual-capable missiles. China meanwhile tightens the screws on Taiwan as it cements its friendship with Russia and continues its buildup of strategic nuclear warheads.1 Conventional wisdom and U.S. policy under such tense conditions unduly discount expectations for arms control.2 Arms control, in the popular mind, centers on bans in testing or deployment, and is therefore terminally associated with disarmament. Trepidation about disarmament fuels assumptions in polarized democracy, and the United States in particular, about the narrow political conditions under which arms control can succeed during great power competition. Conventional …

Drone-Based, Boost-Phase Intercept Of North Korean Icbms, James D. Wells, William Priedhorsky, Frederick Lamb, Laura Grego

Space and Defense

North Korea currently has an adversarial relationship with the United States and has successfully tested both nuclear weapons and intercontinental-range ballistic missiles (ICBMs) capable of striking the continental United States.1 There are several ways the United States could attempt to address the threat posed by North Korea’s nuclear-armed ICBMs. Historically, the United States has relied on a policy of projecting military strength, fostering strong alliances, and maintaining a credible threat of retaliation to deter adversaries, including those with nuclear weapons, from initiating hostilities. Some have argued that this approach has been instrumental in preventing conflict between nuclear-armed nations, including North …

A Premature Obituary For Conventional Deterrence, Jeffery S. Lehmkuhl

Space and Defense

As the United States (US) continues to shift its weight of effort towards great power competition, some scholars and practitioners have questioned the relevance of conventional forces and their ability to deter. Chief among them is Sean McFate, who asserts that “conventional war is unicorn hunting” and that “no one fights that way anymore.”1 Jim Sciutto echoes McFate’s claims in his book The Shadow War and states that the US is losing to Russia and China in a new way of warfare that is conducted below the threshold of conventional warfare.2 Leading Russian General Valery Gerasimov furthered this claim when …

Nuclear Regimes In The 21st Century, Stephen J. Cimbala, Adam Lowther

Space and Defense

The modern nuclear operations practitioner is facing a more complex future than at any point since the height of the Cold War. Understanding the past, present, and possible future of nuclear force structure and doctrine offers the policy maker a useful way to make sense of unfolding events and place them within a broader context. With China, Russia, and North Korea all posing a growing nuclear risk to the United States, a strong grasp on the available options for countering these threats is certainly important.

Editor's Note, Damon Coletta

Space and Defense

No abstract provided.

Table Of Contents Vol. 15 No. 2

Space and Defense

No abstract provided.

Space And Defense Vol. 15 No. 2 Fall 2024 (Whole Issue)

Space and Defense

No abstract provided.

Heat Transfer In Tightly Packed Cylinder Arrays, Martin Kovachev

Doctoral Dissertations and Master's Theses

Cylindrical arrays with a cross flow are commonly used for heat transfer augmentation within an internal channel. In most applications, the cylinders have a spacing of over 2 diameters (2D) between their center points in both the lateral and downstream directions. One option for battery thermal management in hybrid/electric aviation is to use cylindrical batteries packed in arrays with an applied cross flow. In the context of aviation, it is important to maximize space and weight savings. Tightly packing these cylinder arrays with a spacing of under 2D in both directions would save on both of these yet have not …

A Low-Complexity Algorithm For Trajectory Generation In The Three-Body Problem, Brian P. Baker-Mcevilly

Doctoral Dissertations and Master's Theses

The Cislunar realm holds intrinsic value for scientific, commercial, and military applications as numerous entities have begun to invest resources into the expansion and utilization of the region. As the Cislunar region continues to grow, there is an escalating need for efficient methods of trajectory generation in this multi-body dynamical system for computationally limited systems. Thus, a low-complexity classical algorithm is proposed to achieve accurate orbital trajectories in the three-body problem. The proposed algorithm solves a polynomial interpolation problem, formulated using state measurements, through the unique decomposition of a dense system into sparse matrices. Several relevant Cislunar trajectories are simulated …

Nasa Microgreen Cultivation In Space Utilizing Pegda Hydrogels, Thomas Alarcon Ali, Zohaib Gabriel Khan, Ariel Marroquin, Samuel Martinez, Fabiha Samiha, Emily Yong

Publications and Research

During long-term space expeditions, it is crucial that astronauts receive the nutrients they need to maintain their overall health. While the current space diet of palatable foods is commendable and constantly evolving, nutritional content and food quality degrades over long durations. Microgreens are excellent candidates for space cultivation because they are nutrient-dense, young plants that are are densely grown and harvested when leaves are just emerging. However, antigravity, microgreen fragility, degradation speed, contamination, and limited water resources are substantial barriers to doing so. This study aims to address these challenges by cultivating microgreens inside a hydrogel, a soilless medium, to …