Aerospace Engineering Commons^™

Implementation Of Experimental Static Recrystallization Of High Strength Steel Into Computational Simulation Of Multi-Pass Slab Hot Rolling, S. K. Dasari, S. Ganguly, A. Abutunis, K. Chandrashekhara, M. F. Buchely, S. N. Lekakh, R. J. O'Malley, T. Natarajan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microstructural changes and softening due to static recrystallization have a critical influence on thermo-mechanical behavior of high strength steels during industrial multi-pass hot rolling. Numerical simulation using finite element analysis (FEA) can be used to accurately predict the softening behavior during the hot rolling process. Therefore, the implementation of an experimentally defined static recrystallization model into FEA is necessary to get realistic simulation prediction. in this study, the extent of softening during static recrystallization in Si and Mn alloyed high strength steel was measured using double hit tests. a Gleeble™ thermo-mechanical simulator was used to perform the double hit tests …

Design Of Impact-Free Gaits For Planar Bipeds And Their Stabilization Using Impulsive Control, Aakash Khandelwal, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of designing and stabilizing impact-free gaits is considered for point-foot planar bipeds. A set of geometric constraints, which eliminate impact forces at the time of leg interchange, are used to design the gaits. A family of gaits, where the stride length and walking speed can be chosen independently for each gait, is guaranteed to exist. A continuous controller is used to enforce the constraints associated with a desired gait and intermittent impulsive inputs are applied to stabilize the gait. A five-link biped example is used to illustrate the procedure for designing impact-free gaits. The effectiveness of the continuous …

Flying To Net Zero With Sustainable Atos; Changing Cultures​, Eva Maleviti

Publications

What is Sustainability?

• World Commission on Environment and Development’s (WCED) 1987 Brundtland Report ‘’Our Common Future’’.
• Help world nations towards sustainable development.

17 Sustainable Development Goals

• The start of all industries are the 17 SDGs
• Aviation can address the 15 SDGs
• Net zero target suggest reduction of aviation emissions up to 21.2 Gt CO2

Searching For Unknown Material Properties For Am Simulations, Aaron Flood, Rachel Boillat, Sriram Praneeth Isanaka, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Additive manufacturing (AM) simulations are effective for materials that are well characterized and published; however, for newer or proprietary materials, they cannot provide accurate results due to the lack of knowledge of the material properties. This work demonstrates the process of the application of mathematical search algorithms to develop an optimized material dataset which results in accurate simulations for the laser directed energy deposition (DED) process. This was performed by first using a well-characterized material, Ti-64, to show the error in the predicted melt pool was accurate, and the error was found to be less than two resolution steps. Then, …

Design And Fem Modelling Of Mems Capacitive Accelerometer And Gyroscope For Quadcopter/Uav Applications, Shaikha Rashid Alnaqbi

Theses

This study presents the design, simulation, and analysis of Micro Electromechanical Systems (MEMS) sensors, constituting the principal components of MEMS-based Inertial Measurement Units (IMUs). The main objective of the study is to design, simulate and analyze 3-axis capacitive accelerometer and 3-axis gyroscope. The MEMS-based capacitive accelerometers and gyroscope are analyzed using Ansys Workbench. Modal, Static Structural and harmonic analysis are used to obtain resonant frequencies, deformation/stress and profile of amplitude over a wide range of frequencies. Mechanical sensitivity analysis of the designed accelerometer and gyroscope is performed using the Finite Element Method (FEM). Analytical Equations are developed to calculate mechanical …

Development Of A Vortex-Cooled Bipropellant Thruster And Evaluation Of Performance Characteristics With Respect To Injection Parameters, Mousa Adnan Aqailan

Theses

This study presents an experimental assessment of the cooling performance and efficiency of a 10N-vortex-cooled Propane/Gox bi-propellant thruster that was fabricated using metal and thermoplastic material. The proposal of injecting an oxidizer in a vortex pattern was suggested as a potential cooling method for semi-thermoplastic constructed thrust engines. This method has been demonstrated as a promising candidate for integrated cooling and can be manufactured using 3D printing technology. In contrast to typical complicated cooling systems and their attributed common downsides; the vortex injection can be 3D printed as a single solid piece thruster, thereby reducing design complexity, weight, and manufacturing …

Electromagnetic Mems Safety And Arming Devices, Fatima Rashed Alnuaimi

Theses

This thesis aims to investigate the design of safety and arming devices within artillery fuzes, which rely on the spin velocity and setback acceleration of the weapon. These systems consist of two critical components: the spin lock and the inertia lock. The spin velocity and setback acceleration of the weapon induce deformations in these components, serving as key criteria for determining whether the weapon is in an armed or safe state.

The primary objective of this thesis is to comprehensively analyze and assess the design of both the spin lock and inertia lock. The research will delve into multiple factors …

Towards A Virtual Test Framework To Predict Residual Compressive Strength After Lightning Strikes, Scott L.J. Millen, Xiaodong Xu, Juhyeong Lee, Suparno Mukhopadhyay, Michael R. Wisnom, Adrian Murphy

Mechanical and Aerospace Engineering Faculty Publications

A novel integrated modelling framework is proposed as a set of coupled virtual tests to predict the residual compressive strength of carbon/epoxy composites after a lightning strike. Sequentially-coupled thermal-electric and thermo-mechanical models were combined with Compression After Lightning Strike (CAL) analyses, considering both thermal and mechanical lightning strike damage. The predicted lightning damage was validated using experimental images and X-ray Computed Tomography. Delamination and ply degradation information were mapped to a compression model, with a maximum stress criterion, using python scripts. Experimental data, in which artificial lightning strike and compression testing were performed, was used to assess the predictive capabilities …

On Quantifying Uncertainty In Lightning Strike Damage Of Composite Laminates: A Hybrid Stochastic Framework Of Coupled Transient Thermal-Electrical Simulations, R. S. Chahar, J. Lee, T. Mukhopadhyay

Mechanical and Aerospace Engineering Faculty Publications

Lightning strike damage can severely affect the thermo-mechanical performance of composite laminates. It is essential to quantify the effect of lightning strikes considering the inevitable influence of material and geometric uncertainties for ensuring the operational safety of aircraft. This paper presents an efficient support vector machine (SVM)-based surrogate approach coupled with computationally intensive transient thermal-electrical finite element simulations to quantify the uncertainty in lightning strike damage. The uncertainty in epoxy matrix thermal damage and electrical responses of unprotected carbon/epoxy composite laminates is probabilistically quantified considering the stochasticity in temperature-dependent multi-physical material properties and ply orientations. Further, the SVM models are …

Aerodynamic & Aeroacoustic Performance Of Wind Turbine Blades Featuring Enhanced Flow-Control, Md Zishan Akhter

Dissertations

Wind energy, being one of the cleanest and most sustainable sources, has undergone remarkable growth in recent years due to advancements in aerodynamics and increased power output. The research community is actively pursuing the development of cutting-edge solutions to further optimize wind turbine technology, ensuring its maximum efficiency and revolutionizing the landscape of wind power.
/="/">This research aims to design and develop flow-control devices for wind turbine blades, employing both active and passive control mechanisms, namely morphing trailing-edge and slot-profile, respectively. The objective is to enhance wind turbine performance across a wide range of wind speeds. The morphing trailing-edge …

Exploring Underwater Noise Issues : A Study Of Decentralized Approach, Takanori Uzumaki

World Maritime University Dissertations

No abstract provided.

Notes For Contributors, Space And Defense

Space and Defense

No abstract provided.

Cadet Voice: A Curious Trinity: War, Media, And Public Opinion, Laura Olson

Space and Defense

The following USAFA cadet Capstone project from spring 2017 won the Best Undergraduate Class Paper Award from the national Political Science honor society, Pi Sigma Alpha. The article appears, below, as submitted, with allowances for Space & Defense formatting.

August, 2012- President Obama drew a “Red Line” on chemical weapons use in Syria. Just over a year later, a UN report confirmed Syrian chemical use. Two words, spoken by the most powerful man in the world, generated massive media coverage. Around the world, news outlets and people everywhere looked for Washington’s reaction. Words are powerful because of the narrative they …

Arms Control And Deterrence In The Age Of Cross-Domain Coercion, Damon Coletta

Space and Defense

For deterrence, now, first seek arms control. The old relationship linking deterrence, defense, and arms control served U.S. policy makers for decades during the Cold War. It was manifest through the Spirit of Geneva (1955) and the Reykjavik Summit (1986). Much later, during the rise of cross-domain coercion and following Russia’s annexation of Crimea, the same idea reemerged in NATO’s Warsaw Communique (2016).

Building Beyond Samba And Soccer: Why Brazil Ventured A Nuclear Program, Saint-Clair Lima Da Silva

Space and Defense

Contrary to conventional wisdom on Brazil as a case of nuclear proliferation, archival evidence indicates that, rather than geopolitical rivalry with Argentina, enduring desire for national autonomy—honor more than sword or shield—drove Brazil during the 1980s to master its own uranium enrichment cycle.

Communicating Cyber Consequences, Timothy Goines

Space and Defense

More consideration ought to be accorded “loud” cyber weapons for signaling resolve in 21st century deterrence contests.

“Deterrence is at times a necessary or useful instrument of foreign policy, but the correct and prudent use of deterrence strategy is by no means self-evident or easily determined in all circumstances.”

In their seminal text, Alexander L. George and Richard Smoke thoroughly examined the topic of deterrence, tracing its historical roots and conducting case studies on its use. The product of this intense study was a formula that encapsulates the essence of deterrence theory. “In its simplest form, deterrence is merely a …

China's Military Space Strategy: A Dialectical Materialism Perspective, Sam Rouleau

Space and Defense

China’s military space strategy accommodates in significant ways the Chinese Communist Party’s (CCP’s) ideological commitment to dialectical materialism. This Marxian commitment persists and manifests in China’s investment in space power despite the Party’s widely acknowledged development of state capitalism to guide China’s economy.

Editor's Note Volume 11 No. 1, Damon Coletta

Space and Defense

No abstract provided.

Table Of Contents Volume 11 No. 1, Space And Defense

Space and Defense

No abstract provided.

Front Matter Volume 11 No. 1, Space And Defense

Space and Defense

No abstract provided.