Mechanical Engineering Commons^™

Thermal-Fatigue And Thermo-Mechanical Equivalence For Transverse Cracking Evolution In Laminated Composites, Javier Cabrera Barbero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Carbon fiber reinforced plastics (CFRP) are potential materials for many aerospace and aeronautical applications due to their high specif strength/weight and a low coeffcient of thermal expansion (CTE) resulting in a high long-term stability. Among candidate structures, the re-entry reusable launch vehicles (RLV), the fuel oxidant storage and transportation at cryogenic temperature, space satellites, and aircraft structure (frame, wings, etc...) can be highlighted. However, CFRP are prone to internal damage as a result of high residual stresses and thermal fatigue loading. In this study, micro-cracking damage evolution in laminated composites subjected to monotonic cooling and thermal cyclic loads is developed …

The Nakahara Effect And Its Influence On Solution-Based 3d Printed Films, Daryl Kwakye-Ackah

Graduate Theses, Dissertations, and Problem Reports (ETD)

Motivated by the Nakahara Effect, the influence of altering printing parameters on fragmentation mechanism(s) of directly written titanium dioxide(TiO₂) films is investigated. The Nakahara effect states that a long lasting memory can be introduced into a colloidal system prior to drying, affecting the type of crack pattern formed due to externally applied forces. TiO₂ has important applications due to its interesting semiconducting properties, tunable band gap, photocatalytic properties, biocompatibility, and relative abundance. This is the reason it is used in this project as a model printing ink system.

In this research, two deposition methods (i.e. direct-ink writing …

Uncertainty In Combustion Reaction Rates And Its Effects On Combustion Simulations, Joshua Piehl

Wayne State University Theses

This work investigates the uncertainties in reaction rates of an n-dodecane model on turbulent spray combustion simulations. Six major reactions were found to significantly impact the ignition delay of the mechanism in a 0-D batch reactor model. These reactions’ rates were independently modified and placed into individual mechanisms. These newly developed mechanisms were simulated in a 3-D turbulent spray simulation and a 0-D batch reactor at a pressure of 60 bar and temperatures from 900 to 1100 K. The combustion characteristics (e.g. ignition delays, flame lift-off length, liquid and vapor penetration) of the modified mechanisms were compared to those produced …

Including Topographical Effects In Slant-Range Modeling, Kari C. Ward, Kyle J. Demarsy

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spacecraft descent-to-landing navigation often includes the use of a slant-range measurement, the distance from the spacecraft to a surface along the off-nadir pointing direction of the sensor. Modeling a slant range sensor requires a reference surface, approximations of which include spherical and ellipsoidal surfaces, spherical harmonic models, and topographical maps based on prior reconnaissance data. For the spherical and ellipsoidal reference surfaces, a closed-form solution of the slant-range measurement exists. However, these approaches are inaccurate with respect to the true surface. This paper develops a method to implement digital elevation maps of a given surface to create a topography-based model …

Square-Root Consider Filters With Hyperbolic Householder Reflections, James S. Mccabe, Kyle J. De Mars

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Maintaining positive definiteness of a filter's error covariance estimate is of paramount importance to any stable and reliable estimation scheme. Two widely used methods for protecting a filter from loss of positive-definiteness are that of consider filtering and square-root filtering. Despite their widespread use in estimation applications, a filtering methodology that combines the two techniques has yet to be presented in a unified, streamlined architecture. This paper develops a new approach to square-root filtering using hyperbolic Householder reflections. A specialization of the method is considered to permit computationally efficient applications, and a numerical example pertaining to a ballistic reentry is …

Tortuosity Calculations, Blood Flow Simulations, And Mechanical Testing Of Mouse Aortae, Shawn Pavey, Jessica Wagenseil

Undergraduate Research Symposium Posters

Aortic aneurysms can lead to wall rupture or dissection, which are both deadly occurrences. The risk of developing problematic aneurysms increases with age, making them a growing concern in the USA’s aging population. Thoracic Aortic Aneurysm (TAA) treatment is highly effective if the TAA is diagnosed in time, however current surgical guidelines catch less than half of fatal TAA cases. Tortuosity (related to vessel length divided by the straight distance between two points of interest) has been proposed as a supplement to diameter based diagnosis of severity of TAA progression. This study aimed to confirm the validity of that proposal …

Distributed Electric Propulsion Effects On Traditional Aircraft Through Multidisciplinary Optimization, Kevin Moore, Andrew Ning

Faculty Publications

Electric aircraft face a steep tradeoff between the demand for runway performance and range. While fuel based propulsion technologies typically increase in specific power with increasing size, electric propulsion is typically much more scalable. This system scalability enables alternative designs including distributed propulsion, optionally powered propulsion units, and vectored thrust, which can all contribute to better runway performance and range. In this paper, we explore how continuously powered distributed propulsion can reduce takeoff distance while still satisfying range constraints. We use a combination of a blade element momentum method, a vortex lattice method, experimental data, and nonlinear optimization techniques to …

Multidisciplinary Design Optimization Of Flexible Solar-Regenerative High-Altitude Long-Endurance Aircraft, Taylor Mcdonnell, Judd Mehr, Andrew Ning

Faculty Publications

Solar-Regenerative High-Altitude Long-Endurance (SR-HALE) aircraft are designed to sustain year-round flight at high altitudes indefinitely. No SR-HALE aircraft has yet accomplished this task due to the complex network of environmental, solar, structural, and aerodynamic trade-offs, among which aircraft flexibility plays a key role. A comprehensive SR-HALE aircraft multidisciplinary design optimization framework is developed in which the flexible aircraft analysis tool ASWING is incorporated in order to constrain nonlinear aeroelasticity. Energy, battery, ply thickness, material failure, local buckling, aerodynamic stall, longitudinal stability, and general stability (including flutter) constraints are applied in order to reasonably constrain the optimized SR-HALE aircraft design. An …

Benefits Of Two Turbine Rotor Diameters And Hub Heights In The Same Wind Farm, Andrew Pj Stanley, Andrew Ning, Katherine Dykes

Faculty Publications

Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with …

Large-Scale Multidisciplinary Optimization Of An Electric Aircraft For On-Demand Mobility, John Hwang, Andrew Ning

Faculty Publications

Distributed electric propulsion is a key enabling technology for on-demand electric aircraft concepts. NASA’s X-57 Maxwell X-plane is a demonstrator for this technology, and it features a row of high-lift propellers distributed along the leading edge of its wing to enable better aerodynamic efficiency at cruise and improved ride quality in addition to less noise and emissions. This study applies adjoint- based multidisciplinary design optimization to this highly coupled design problem. The propulsion, aerodynamics, and structures are modeled using blade element momentum theory, the vortex lat- tice method, and finite element analysis, respectively, and the full mission profile is discretized …

Fpga-Based On-Board Geometric Calibration For Linear Ccd Array Sensors, Guoqing Zhou, Linjun Jiang, Jingjin Huang, Rongting Zhang, Dequan Liu, Xiang Zhou, Oktay Baysal

Mechanical & Aerospace Engineering Faculty Publications

With increasing demands in real-time or near real-time remotely sensed imagery applications in such as military deployments, quick response to terrorist attacks and disaster rescue, the on-board geometric calibration problem has attracted the attention of many scientists in recent years. This paper presents an on-board geometric calibration method for linear CCD sensor arrays using FPGA chips. The proposed method mainly consists of four modules—Input Data, Coefficient Calculation, Adjustment Computation and Comparison—in which the parallel computations for building the observation equations and least squares adjustment, are implemented using FPGA chips, for which a decomposed matrix inversion method is presented. A Xilinx …

Linear Burn Rate Of Monopropellant For Multi-Mode Micropropulsion, Alex J. Mundahl, Steven P. Berg, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-mode micro propulsion is a technology that can enable rapidly composable small satellites with unprecedented mission flexibility. To maximize mission flexibility a multi-mode micro propulsion monopropellant must be shared between the chemical and electric propulsion modes. Previous research has identified a promising monopropellant that is both readily catalytically exothermically decomposed (chemical mode) and electro sprayable (electric mode). In this work the linear burn rate of this monopropellant is determined and used to aid the design of a microtube catalytic chemical thruster. Experiments with a pressurized fixed volume reactor are used to determine the linear burn rate. Benchmark experiments use a …

Mechanical Annealing Of Model Glasses: Effects Of Strain Amplitude And Temperature, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

Molecular dynamics simulations are performed to examine the dynamic response of amorphous solids to oscillatory shear at finite temperatures. The data were collected from a poorly annealed binary glass, which was deformed periodically in the elastic regime during several hundred shear cycles. We found that the characteristic time required to reach a steady state with a minimum potential energy is longer at higher temperatures and larger strain amplitudes. With decreasing strain amplitude, the asymptotic value of the potential energy increases but it remains lower than in quiescent samples. The transient decay of the potential energy correlates well with a gradual …

Strong Stability Of A Class Of Difference Equations Of Continuous Time And Structured Singular Value Problem, Qian Ma, Keqin Gu, Narges Choubedar

SIUE Faculty Research, Scholarship, and Creative Activity

This article studies the strong stability of scalar difference equations of continuous time in which the delays are sums of a number of independent parameters tau_i, i = 1, 2, . . . ,K. The characteristic quasipolynomial of such an equation is a multilinear function of exp(-tau_i s). It is known that the characteristic quasipolynomial of any difference equation set in the form of one-delayper- scalar-channel (ODPSC) model is also in such a multilinear form. However, it is shown in this article that some multilinear forms of quasipolynomials are not characteristic quasipolynomials of any ODPSC difference equation set. The equivalence …

Strong Stability Of A Class Of Difference Equations Of Continuous Time And Structured Singular Value Problem, Qian Ma, Keqin Gu, Narges Choubedar

SIUE Faculty Research, Scholarship, and Creative Activity

This article studies the strong stability of scalar difference equations of continuous time in which the delays are sums of a number of independent parameters τi, i = 1, 2, . . . , K. The characteristic quasipolynomial of such an equation is a multilinear function of e−τis. It is known that the characteristic quasipolynomial of any difference equation set in the form of one-delay-per-scalar-channel (ODPSC) model is also in such a multilinear form. However, it is shown in this article that some multilinear forms of quasipolynomials are not characteristic quasipolynomials of any ODPSC difference equation set. The equivalence between …

Test 2207: Challenger Mt743, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2204: John Deere 5090m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2203: John Deere 9420rx, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2200a: New Holland Workmaster 70, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2200: Case Ih Farmall 70a, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2194: John Deere 5100r Pfc, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2191: John Deere 5090r Oc, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

The Effect Of Friction Stir Processing On The Microstructure And Tensile Behavior Of Aluminum Alloys, Nelson Gomes Affonseca Netto

UNF Graduate Theses and Dissertations

Friction Stir Processing (FSP) is a promising thermomechanical technique that is used to modify the microstructure of metals locally, and thereby locally improve mechanical properties of the material. FSP uses a simple and inexpensive tool, and has been shown to eliminate pores and also reduce the sizes of intermetallics in aluminum alloys. This is of great interest for research on solidification, production and performance of aluminum alloy castings because FSP can enhance the structural quality of aluminum casting significantly by minimizing the effect of those structural defects.

In the literature, there is evidence that the effectiveness of FSP can change …

Potential Replacement Of The Us Navy's Rapid Penetration Test With The Method Of Multichannel Analysis Of Surface Waves, William Fletcher

UNF Graduate Theses and Dissertations

The United States Navy (USN) currently utilizes a Rapid Penetration Test (RPT) on both land and in water as the means to determine whether sufficient soil bearing capacity exists for piles in axial compression, prior to construction of the Elevated Causeway System (Modular) [ELCAS(M)] pile-supported pier system. The USN desires a replacement for the RPT because of issues with the method incorrectly classifying soils as well as the need to have a less labor-and-equipment-intensive method for geotechnical investigation.

The Multichannel Analysis of Surface Waves (MASW) method is selected herein as the potential replacement for the RPT. The MASW method is …

The Microstructural Annealing Response Of Cold Gas Dynamically Sprayed Al 6061, Clayton Andrew Cushway

UNF Graduate Theses and Dissertations

The Cold-Gas Dynamic-Spray process also known as Cold Spray (CS) has been researched for three decades. The CS process is a solid-state deposition technique via supersonic velocity of powder particles at a temperature significantly below the melting point of the spray material. This thesis presents background on the overall CS process parameters, and additional information on the microstructural and mechanical properties of typical Cold Sprayed materials.This Thesis primarily presents a study on the microstructural annealing response of CS Al 6061. It should be noted that for this study, the term “annealing” is used in the sense of the classical metallurgical …

Electrowetting Using A Microfluidic Kelvin Water Dropper, Elias Yazdanshenas, Qiang Tang, Xiaoyu Zhang

Mechanical & Aerospace Engineering Faculty Publications

The Kelvin water dropper is an electrostatic generator that can generate high voltage electricity through water dripping. A conventional Kelvin water dropper converts the gravitational potential energy of water into electricity. Due to its low current output, Kelvin water droppers can only be used in limited cases that demand high voltage. In the present study, microfluidic Kelvin water droppers (MKWDs) were built in house to demonstrate a low-cost but accurately controlled miniature device for high voltage generation. The performance of the MKWDs was characterized using different channel diameters and flow rates. The best performed MKWD was then used to conduct …

Tuskegee University Amateur Radio Station- Vhf/Uhf Digital Communication With Legacy Systems, Sharanabasaweshwara A. Asundi, Sharath S. Byakod

Mechanical & Aerospace Engineering Faculty Publications

No abstract provided.

Mechanism Design Of A Compact 4-Dof Robotic Needle Guide For Mri-Guided Prostate Intervention, Shihao Zhang

Electronic Theses and Dissertations

In the past several MRI compatible robotic needle guide devices for targeted prostate biopsy have been developed. The large and complex structure have been identified as the major limitations of those devices. Such limitations, in addition to complex steps for device to image registration have prevented widespread implementation of MRI-guided prostate biopsy despite the advantages of MRI compared to TRUS. We have designed a compact MRI-guided robotic intervention with the capability to have angulated insertion to avoid damage to any anatomical feature along the needle path. The system consists of a novel mechanism driven Robotic Needle Guide (RNG). The RNG …

A Framework For Miniaturized Mechanical Characterization Of Tensile, Creep, And Fatigue Properties Of Slm Alloys, Jonathan Torres-Caceres

Electronic Theses and Dissertations

With the heightened design complexity that may be achieved through additive manufacturing (AM) comes an equally complex set of distinct material characteristics. To properly characterize new materials for use in selective laser melting (SLM), extensive analysis is necessary. Traditional testing techniques, however, can be prohibitive in time and cost incurred. The small punch test (SPT) has been developed for such purposes, where material is scarce or costly. Although lacking standardization, SPT has been successfully employed with various materials to assess material properties such as the yield and ultimate strength and verified by traditional testing results. With the accompaniment of numerical …

Multi-Scale Fluid-Structure Interaction Model Analysis Of Patient-Specific Geometry For Optimization Of Lvad Outflow Graft Implantation: An Investigation Aimed At Reducing Stroke Risk, Ray Prather

Electronic Theses and Dissertations

A Left Ventricular Assist Device (LVAD), is a mechanical pump capable of providing circulatory myocardium relief when used as bridge-to-transplantation by reducing the workload of a failing heart, with the additional bonus of allowing for cardiac recovery when used as destination therapy. The newer generations of continuous flow VADs are essentially axial or radial flow pumps, and while these devices are capable their efficiency depends upon fluid composition and flow field patterns. The most devastating complication of VAD therapy is caused by embolization of thrombi formed within the LVAD or inside the heart into the brain leading to stroke. Anticoagulation …