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Articles 61 - 90 of 118
Full-Text Articles in Aerospace Engineering
An Argument Against Satellite Resiliency: Simplicity In The Face Of Modern Satellite Design, Dax Linville, Robert A. Bettinger
An Argument Against Satellite Resiliency: Simplicity In The Face Of Modern Satellite Design, Dax Linville, Robert A. Bettinger
Faculty Publications
The US Air Force and the wider US government rely heavily on space-based capabilities in various orbital regimes to project national security and sovereignty. However, these capabilities are enabled by the design, launch, and operation of satellites produced with a design methodology that favors large, monolithic, and technologically exquisite space systems. Despite the ability for these satellites to provide enduring and resilient capabilities, they suffer from a woefully long acquisition process that debilitates any prospect of rapid satellite reconstitution in the event of a space war.
Magslam: Aerial Simultaneous Localization And Mapping Using Earth's Magnetic Anomaly Field, Taylor N. Lee, Aaron J. Canciani
Magslam: Aerial Simultaneous Localization And Mapping Using Earth's Magnetic Anomaly Field, Taylor N. Lee, Aaron J. Canciani
Faculty Publications
Instances of spoofing and jamming of global navigation satellite systems (GNSSs) have emphasized the need for alternative navigation methods. Aerial navigation by magnetic map matching has been demonstrated as a viable GNSS‐alternative navigation technique. Flight test demonstrations have achieved accuracies of tens of meters over hour‐long flights, but these flights required accurate magnetic maps which are not always available. Magnetic map availability and resolution vary widely around the globe. Removing the dependency on prior survey maps extends the benefits of aerial magnetic navigation methods to small unmanned aerial systems (sUAS) at lower altitudes where magnetic maps are especially undersampled or …
Unsteady Aerodynamic Analysis Of Wind Harvesting Aircraft, Judd Mehr, Eduardo Alvarez, Andrew Ning
Unsteady Aerodynamic Analysis Of Wind Harvesting Aircraft, Judd Mehr, Eduardo Alvarez, Andrew Ning
Faculty Publications
Airborne Wind Energy (AWE) technology aspires to provide increased options for wind energy harvesting. This includes increased feasibility for temporary and remote installations, as well as the ability to operate at wind speeds both lower and higher than traditional turbines. Additionally, the hope is to be able to produce these extensions of wind energy technology at a lower cost than conventional technologies. As AWE technology is still in its infancy, however, there is very little published information concerning the aerodynamic details of the technology. We have created a set of aerodynamic analysis tools which we apply to wind harvesting aircraft, …
Peak Pressures On Low Rise Buildings: Cfd With Les Versus Full Scale And Wind Tunnel Measurements, Aly Mousaad Aly, Hamzeh Gol-Zaroudi
Peak Pressures On Low Rise Buildings: Cfd With Les Versus Full Scale And Wind Tunnel Measurements, Aly Mousaad Aly, Hamzeh Gol-Zaroudi
Faculty Publications
This paper focuses on the processes of wind flow in the atmospheric boundary layer, to produce realistic full-scale pressures for the design of low-rise buildings. CFD with LES turbulence closure is implemented on a scale 1:1 prototype building. A proximity study was executed computationally in CFD with LES that suggests new recommendations on the computational domain size, in front of a building model, apart from common RANS-based guidelines (e.g. COST and AIJ). Our findings suggest a location of the test building, different from existing guidelines, and the inflow boundary proximity influences pressure correlation and reproduction of peak loads. The CFD …
Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Dustin P. Graves, Kyle D. Moore, Anthony N. Palazotto
Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Dustin P. Graves, Kyle D. Moore, Anthony N. Palazotto
Faculty Publications
Excerpt: The celestial icosahedron geometry is considered as a potential design for a vacuum lighter than air vehicle. The goal of this research is ultimately to determine the feasibility of the design and to understand the initial fluid-structure interaction of the vacuum lighter than air vehicle and the surrounding airflow.
Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders
Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders
Faculty Publications
Solar neutrons have been detected aboard the International Space Station (ISS), using lithium tetraborate and boron carbide detector elements. We find that evidence of a solar neutron flux, as detected in a neutron calorimeter following subtraction of the proton background, with an energy of about 2 to 4 MeV. This solar neutron flux is likely no more than 250 to 375 neutrons cm−2sec−1, with a lower bound of 50–75 neutrons cm−2sec−1 at one au.
Ion Software-Defined Radio Metadata Standard Final Report, Sanjeev Gunawardena, Alexander Rugamer, Muhammad Subhan Hameed, Markel Arizabaleta, Thomas Pany, Javier Arribas
Ion Software-Defined Radio Metadata Standard Final Report, Sanjeev Gunawardena, Alexander Rugamer, Muhammad Subhan Hameed, Markel Arizabaleta, Thomas Pany, Javier Arribas
Faculty Publications
The ION GNSS SDR Metadata Standard describes the formatting and other essential PNT-related parameters of sampled data streams and files. This allows processors to seamlessly consume such data without the need to input these parameters manually. The technical development phase of the initial version of the standard has now been deemed complete and is currently undergoing the last remaining procedural steps towards adoption as a formal standard by the Institute of Navigation. This paper reports on the activities of the working group since September 2018 and summarizes the final products of the standard. It also reports on examples of early …
The Potentiality Of Space Enterprise Force Reconstitution: Nationalizing Civilian Satellites During Kinetic Conflicts, Robert A. Bettinger, Sara Schmitt
The Potentiality Of Space Enterprise Force Reconstitution: Nationalizing Civilian Satellites During Kinetic Conflicts, Robert A. Bettinger, Sara Schmitt
Faculty Publications
This article will discuss the possibility of employing a policy of civilian satellite nationalization during a space war as a means of US Space Enterprise force re- constitution to ensure continued access to space capabilities necessary for the execution of the national strategy, as well as deterring potential adversaries from initiating counterspace hostilities. In terms of structure, the authors will examine the thesis by answering these questions. First, what historical precedent exists for the rapid military acquisition of civilian assets via nationalization? Second (given the unique nature of space as an operational environment), can that historical precedent be applied to …
First Approach To Coupling Of Numerical Lifting-Line Theory And Linear Covariance Analysis For Uav State Uncertainty Propagation, Cory D. Goates, Randall S. Christensen, Robert C. Leishman
First Approach To Coupling Of Numerical Lifting-Line Theory And Linear Covariance Analysis For Uav State Uncertainty Propagation, Cory D. Goates, Randall S. Christensen, Robert C. Leishman
Faculty Publications
Numerical lifting-line is a computationally efficient method for calculating aerodynamic forces and moments on aircraft. However, its potential has yet to be tapped for use in guidance, navigation, and control (GN&C). Linear covariance analysis is becoming a popular GN&C design tool and shows promise for pairing with numerical lifting-line. Pairing numerical lifting-line with linear covariance analysis allows for forward propagation of state uncertainty for real-time decision making. We demonstrate this for select state variables in a drone aerial recapture situation. Linear covariance analysis uses finite difference derivatives obtained from numerical lifting-line to calculate force and moment variances. These show agreement …
Real-Time Path Planning In Constrained, Uncertain Environments, Randall Christensen, Robert C. Leishman
Real-Time Path Planning In Constrained, Uncertain Environments, Randall Christensen, Robert C. Leishman
Faculty Publications
A key enabler of autonomous vehicles is the ability to plan the path of the vehicle to accomplish mission objectives. To be robust to realistic environments, path planners must account for uncertainty in the trajectory of the vehicle as well as uncertainty in the location of obstacles. The uncertainty in the trajectory of the vehicle is a difficult quantity to estimate, and is influenced by coupling between the vehicle dynamics, guidance, navigation, and control system as well as any disturbances acting on the vehicle. Monte Carlo analysis is the conventional approach to determine vehicle dispersion, while accounting for the coupled …
Dynamic Optimization Of High-Altitude Solar Aircraft Trajectories Under Station-Keeping Constraints, Ronald Abraham Martin, Nathaniel Gates, Andrew Ning, John Hedengren
Dynamic Optimization Of High-Altitude Solar Aircraft Trajectories Under Station-Keeping Constraints, Ronald Abraham Martin, Nathaniel Gates, Andrew Ning, John Hedengren
Faculty Publications
This paper demonstrates the use of nonlinear dynamic optimization to calculate energy optimal trajectories for a high-altitude, solar-powered Unmanned Aerial Vehicle (UAV). The objective is to maximize the total energy in the system while staying within a 3 km mission radius and meeting other system constraints. Solar energy capture is modeled using the vehicle orientation and solar position, and energy is stored both in batteries and in potential energy through elevation gain. Energy capture is maximized by optimally adjusting the angle of the aircraft surface relative to the sun. The UAV flight and energy system dynamics are optimized over a …
Toward Building Resilient, Sustainable, And Smart Infrastructure In The 21st Century, Aly Mousaad Aly
Toward Building Resilient, Sustainable, And Smart Infrastructure In The 21st Century, Aly Mousaad Aly
Faculty Publications
In recent years, as a result of significant climate change, stringent windstorms are becoming more frequent than before. Given the threat that windstorms bring to people and property, wind/structural engineering research is imperative to improve the resilience of existing and new infrastructure, for community safety and assets protection. The Windstorm Impact, Science and Engineering (WISE) research program at Louisiana State University (LSU) focuses on creating new knowledge applicable to the mitigation of existing and new infrastructure, to survive and perform optimally under natural hazards. To achieve our research goals, we address two imperious challenges: (i) characterization of realistic wind forces …
Development Of A Vortex Particle Code For The Modeling Of Wake Interaction In Distributed Propulsion, Eduardo Alvarez, Andrew Ning
Development Of A Vortex Particle Code For The Modeling Of Wake Interaction In Distributed Propulsion, Eduardo Alvarez, Andrew Ning
Faculty Publications
Recent developments in electric aircraft technology have enabled the use of distributed propulsion for the next generation of vertical lift vehicles. However, the ability to rapidly assess the performance of these design concepts, with sufficient fidelity, is a current weakness of this nascent industry. This paper explores the capacity of the viscous Vortex Particle Method (VPM) to model wake interactions found in distributed propulsion. The elements of the vortex particle method are summarized, and a new approach for the calculation of vortex stretching through the complex-step derivative approximation is presented. Preliminary validation is performed on vortex ring cases resembling the …
Case Study: Cooling Channels For Material Testing Applications Using Laser Powder Bed Fusion, Benjamin M. Doane, Ryan P. O'Hara, K. Liu, Carl R. Hartsfield
Case Study: Cooling Channels For Material Testing Applications Using Laser Powder Bed Fusion, Benjamin M. Doane, Ryan P. O'Hara, K. Liu, Carl R. Hartsfield
Faculty Publications
Additive Manufacturing continues to gain a reputation as a key technology that will have a major impact on all aspects of mechanical engineering. The United States Air Force’s (USAF) Air Force Institute of Technology (AFIT), based in Dayton, Ohio, has expanded its AM-focused education and R&D capabilities with the purchase of a Laser Powder Bed Fusion system from Germany’s Concept Laser.
Numerical Simulation Of Heat Transfer And Chemistry In The Wake Behind A Hypersonic Slender Body At Angle Of Attack, Matthew J. Satchell, Jeffrey M. Layng, Robert B. Greendyke
Numerical Simulation Of Heat Transfer And Chemistry In The Wake Behind A Hypersonic Slender Body At Angle Of Attack, Matthew J. Satchell, Jeffrey M. Layng, Robert B. Greendyke
Faculty Publications
The effect of thermal and chemical boundary conditions on the structure and chemical composition of the wake behind a 3D Mach 7 sphere-cone at an angle of attack of 5 degrees and an altitude of roughly 30,000 m is explored. A special emphasis is placed on determining the number density of chemical species which might lead to detection via the electromagnetic spectrum. The use of non-ablating cold-wall, adiabatic, and radiative equilibrium wall boundary conditions are used to simulate extremes in potential thermal protection system designs. Non-ablating, as well as an ablating boundary condition using the “steady-state ablation” assumption to compute …
Investigation Into Reynolds Number Effects On A Biomimetic Flapping Wing, Daniel K. Hope, Anthony M. Deluca, Ryan P. O'Hara
Investigation Into Reynolds Number Effects On A Biomimetic Flapping Wing, Daniel K. Hope, Anthony M. Deluca, Ryan P. O'Hara
Faculty Publications
This research investigated the behavior of a Manduca sexta inspired biomimetic wing as a function of Reynolds number by measuring the aerodynamic forces produced by varying the characteristic wing length and testing at air densities from atmospheric to near vacuum. A six degree of freedom balance was used to measure forces and moments, while high speed cameras were used to measure wing stroke angle. An in-house created graphical user interface was used to vary the voltage of the drive signal sent to the piezoelectric actuator which determined the wing stroke angle. The Air Force Institute of Technology baseline 50 mm …
Adaptive Differential Thrust Methodology For Lateral/Directional Stability Of An Aircraft With A Completely Damaged Vertical Stabilizer, Long K. Lu, Kamran Turkoglu
Adaptive Differential Thrust Methodology For Lateral/Directional Stability Of An Aircraft With A Completely Damaged Vertical Stabilizer, Long K. Lu, Kamran Turkoglu
Faculty Publications
This paper investigates the utilization of differential thrust to help a commercial aircraft with a damaged vertical stabilizer in order to regain its lateral/directional stability. In the event of an aircraft losing its vertical stabilizer, the consequential loss of the lateral/directional stability and control is likely to cause a fatal crash. In this paper, an aircraft with a completely damaged vertical stabilizer is investigated, and a unique differential thrust-based adaptive control approach is proposed to achieve a stable flight envelope. The propulsion dynamics of the aircraft is modeled as a system of differential equations with engine time constant and time …
Simplex Solutions For Optimal Control Flight Paths In Urban Environments, Michael D. Zollars, Richard G. Cobb, David J. Grymin
Simplex Solutions For Optimal Control Flight Paths In Urban Environments, Michael D. Zollars, Richard G. Cobb, David J. Grymin
Faculty Publications
This paper identifies feasible fight paths for Small Unmanned Aircraft Systems in a highly constrained environment. Optimal control software has long been used for vehicle path planning and has proven most successful when an adequate initial guess is presented flight to an optimal control solver. Leveraging fast geometric planning techniques, a large search space is discretized into a set of simplexes where a Dubins path solution is generated and contained in a polygonal search corridor free of path constraints. Direct optimal control methods are then used to determine the optimal flight path through the newly defined search corridor. Two scenarios …
Implementing Conditional Inequality Constraints For Optimal Collision Avoidance, Nathan E. Smith, Christopher D. Arendt, Richard G. Cobb, Jonah A. Reeger
Implementing Conditional Inequality Constraints For Optimal Collision Avoidance, Nathan E. Smith, Christopher D. Arendt, Richard G. Cobb, Jonah A. Reeger
Faculty Publications
Current Federal Aviation Administration regulations require that passing aircraft must either meet a specified horizontal or vertical separation distance. However, solving for optimal avoidance trajectories with conditional inequality path constraints is problematic for gradient-based numerical nonlinear programming solvers since conditional constraints typically possess non-differentiable points. Further, the literature is silent on robust treatment of approximation methods to implement conditional inequality path constraints for gradient-based numerical nonlinear programming solvers. This paper proposes two efficient methods to enforce conditional inequality path constraints in the optimal control problem formulation and compares and contrasts these approaches on representative airborne avoidance scenarios. The first approach …
Optimal Trajectory Determination And Mission Design For Asteroid/Deep-Space Exploration Via Multibody Gravity Assist Maneuvers, Sean Fritz, Kamran Turkoglu
Optimal Trajectory Determination And Mission Design For Asteroid/Deep-Space Exploration Via Multibody Gravity Assist Maneuvers, Sean Fritz, Kamran Turkoglu
Faculty Publications
This paper discusses the creation of a genetic algorithm to locate and optimize interplanetary trajectories using gravity assist maneuvers to improve fuel efficiency of the mission. The algorithm is implemented on two cases: (i) a Centaur-class target close to the ecliptic plane and (ii) a Centaur-class target with a high inclination to the ecliptic plane. Cases for multiple numbers of flybys (up to three) are discussed and compared. It is shown that, for the targets considered here, a single flyby of Jupiter is the most efficient trajectory to either target with the conditions and limitations discussed in this paper. In …
Polynomial Chaos For The Computation Of Annual Energy Production In Wind Farm Layout Optimization, Santiago Padrón, Andrew P.J. Stanley, Jared Thomas, Juan Alonso, Andrew Ning
Polynomial Chaos For The Computation Of Annual Energy Production In Wind Farm Layout Optimization, Santiago Padrón, Andrew P.J. Stanley, Jared Thomas, Juan Alonso, Andrew Ning
Faculty Publications
Careful management of wake interference is essential to further improve Annual Energy Production (AEP) of wind farms. Wake effects can be minimized through optimization of turbine layout, wind farm control, and turbine design. Realistic wind farm optimization is challenging because it has numerous design degrees of freedom and must account for the stochastic nature of wind. In this paper we provide a framework for calculating AEP for any relevant uncertain (stochastic) variable of interest. We use Polynomial Chaos (PC) to efficiently quantify the effect of the stochastic variables—wind direction and wind speed—on the statistical outputs of interest (AEP) for wind …
A Hybrid Optimization Technique Applied To The Intermediate-Target Optimal Control Problem, Clay J. Humphreys, Richard G. Cobb, David R. Jacques, Jonah A. Reeger
A Hybrid Optimization Technique Applied To The Intermediate-Target Optimal Control Problem, Clay J. Humphreys, Richard G. Cobb, David R. Jacques, Jonah A. Reeger
Faculty Publications
The DoD has introduced the concept of Manned-Unmanned Teaming, a subset of which is the loyal wingman. Optimal control techniques have been proposed as a method for rapidly solving the intermediate-target (mid-point constraint) optimal control problem. Initial results using direct orthogonal collocation and a gradient-based method for solving the resulting nonlinear program reveals a tendency to converge to or to get `stuck’ in locally optimal solutions. The literature suggested a hybrid technique in which a particle swarm optimization is used to quickly find a neighborhood of a more globally minimal solution, at which point the algorithm switches to a gradient-based …
Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall
Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall
Faculty Publications
The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …
Development Of Cloud-Based Uav Monitoring And Management System, Mason Itkin, Mihui Kim, Younghee Park
Development Of Cloud-Based Uav Monitoring And Management System, Mason Itkin, Mihui Kim, Younghee Park
Faculty Publications
Unmanned aerial vehicles (UAVs) are an emerging technology with the potential to revolutionize commercial industries and the public domain outside of the military. UAVs would be able to speed up rescue and recovery operations from natural disasters and can be used for autonomous delivery systems (e.g., Amazon Prime Air). An increase in the number of active UAV systems in dense urban areas is attributed to an influx of UAV hobbyists and commercial multi-UAV systems. As airspace for UAV flight becomes more limited, it is important to monitor and manage many UAV systems using modern collision avoidance techniques. In this paper, …
Aerodynamic Modeling Of Nrel 5-Mw Wind Turbine For Nonlinear Control System Design: A Case Study Based On Real-Time Nonlinear Receding Horizon Control, Pedro A. Galvani, Fei Sun, Kamran Turkoglu
Aerodynamic Modeling Of Nrel 5-Mw Wind Turbine For Nonlinear Control System Design: A Case Study Based On Real-Time Nonlinear Receding Horizon Control, Pedro A. Galvani, Fei Sun, Kamran Turkoglu
Faculty Publications
The work presented in this paper has two major aspects: (i) investigation of a simple, yet efficient model of the NREL (National Renewable Energy Laboratory) 5-MW reference wind turbine; (ii) nonlinear control system development through a real-time nonlinear receding horizon control methodology with application to wind turbine control dynamics. In this paper, the results of our simple wind turbine model and a real-time nonlinear control system implementation are shown in comparison with conventional control methods. For this purpose, the wind turbine control problem is converted into an optimization problem and is directly solved by the nonlinear backwards sweep Riccati method …
Constructal Alkaline Membrane Fuel Cell (Amfc) Design, E. M. Sommer, J. V. C. Vargas, Lauber De Souza Martins, J. C. Ordonez
Constructal Alkaline Membrane Fuel Cell (Amfc) Design, E. M. Sommer, J. V. C. Vargas, Lauber De Souza Martins, J. C. Ordonez
Faculty Publications
This paper introduces a structured procedure to optimize the internal structure (relative sizes, spacing) and external shape (aspect ratios) of a single alkaline membrane fuel cell so that net power is maximized. The optimization of flow geometry is conducted for the smallest (elemental) level of a fuel cell stack, i.e., the single alkaline membrane fuel cell, which is modeled as a unidirectional flow system. The polarization curve, total and net power, and efficiency are obtained as functions of temperature, pressure, electrolyte solution concentration (KOH), geometry and operating parameters. The optimization is subjected to fixed total volume. There are two levels …
Space Separatism: Degree Of Differentiation, Luke R. Stover, Alan A. Johnson
Space Separatism: Degree Of Differentiation, Luke R. Stover, Alan A. Johnson
Faculty Publications
Space is so important that the DOD recognizes it as one of five domains in which US forces operate (the other four are land, sea, air, and information). In 2001 Secretary of Defense Donald Rumsfeld designated the Department of the Air Force (DAF) the “Executive Agent for Space for the DOD.” Given the national importance of space activities, the formation of a separate space force has been a topic of persistent discussion in academic and doctrinal circles ever since the United States first entered the space age. Proponents of a separate force argue that because space is an inherently unique …
Modeling The Thermosphere As A Driven-Dissipative Thermodynamic System, William R. Frey, C. S. Lin, Matthew B. Garvin, Ariel O. Acebal
Modeling The Thermosphere As A Driven-Dissipative Thermodynamic System, William R. Frey, C. S. Lin, Matthew B. Garvin, Ariel O. Acebal
Faculty Publications
Thermospheric density impacts satellite position and lifetime through atmospheric drag. More accurate specification of thermospheric temperature, a key input to current models such as the High Accuracy Satellite Drag Model, can decrease model density errors. This paper improves the model of Burke et al. (2009) to model thermospheric temperatures using the magnetospheric convective electric field as a driver. In better alignment with Air Force satellite tracking operations, we model the arithmetic mean temperature, T 1/2, defined by the Jacchia (1977) model as the mean of the daytime maximum and nighttime minimum exospheric temperatures occurring in opposite hemispheres at a …
Statistics Based Modeling Of Wind Speed And Wind Direction In Real Time Optimal Guidance Strategies Via Ornstein-Uhlenbeck Stochastic Processes, Kamran Turkoglu
Statistics Based Modeling Of Wind Speed And Wind Direction In Real Time Optimal Guidance Strategies Via Ornstein-Uhlenbeck Stochastic Processes, Kamran Turkoglu
Faculty Publications
No abstract provided.
Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss
Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss
Faculty Publications
The application of guided waves to interrogate remote areas of structural components has been researched extensively in characterizing damage. However, there exists a sparsity of work in using piezoelectric transducer-generated guided waves as a method of assessing stress intensity factors (SIF). This quantitative information enables accurate estimation of the remaining life of metallic structures exhibiting cracks, such as military and commercial transport vehicles. The proposed full wavefield approach, based on 3D laser vibrometry and piezoelectric transducer-generated guided waves, provides a practical means for estimation of dynamic stress intensity factors (DSIF) through local strain energy mapping via the J-integral. Strain energies …