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Full-Text Articles in Engineering

Adaptive Critic Based Neurocontroller For Autolanding Of Aircrafts, S. N. Balakrishnan, Gaurav Saini Jan 1997

Adaptive Critic Based Neurocontroller For Autolanding Of Aircrafts, S. N. Balakrishnan, Gaurav Saini

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, adaptive critic based neural networks have been used to design a controller for a benchmark problem in aircraft autolanding. The adaptive critic control methodology comprises successive adaptations of two neural networks, namely action and critic network (which approximate the Hamiltonian equations associated with optimal control theory) until closed loop optimal control is achieved. The autolanding problem deals with longitudinal dynamics of an aircraft which is to be landed in a specified touchdown region (within acceptable ranges of speed, pitch angle and sink rate) in the presence of wind disturbances and gusts using elevator deflection as the control …


Adaptive Critic Based Neurocontroller For Autolanding Of Aircraft With Varying Glideslopes, Gaurav Saini, S. N. Balakrishnan Jan 1997

Adaptive Critic Based Neurocontroller For Autolanding Of Aircraft With Varying Glideslopes, Gaurav Saini, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, adaptive critic based neural networks have been used to design a controller for a benchmark problem in aircraft autolanding. The adaptive critic control methodology comprises successive adaptations of two neural networks, namely `action' and `critic' networks until closed loop optimal control is achieved. The autolanding problem deals with longitudinal dynamics of an aircraft which is to be landed in a specified touchdown region in the presence of wind disturbances and gusts using elevator deflection as the control for glideslope and flare modes. The performance of the neurocontroller is compared to that of a conventional PID controller. Neurocontroller's …


Radiative Heating In Scramjet Combustors, Harlan F. Nelson Jan 1997

Radiative Heating In Scramjet Combustors, Harlan F. Nelson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Currently, there is considerable interest in scramjet engines for hypersonic aircraft and missiles. This paper presents preliminary calculations of the radiative heating of the walls of scramjet combustion chambers. The analysis assumes isothermal, constant property flow fields that are representative of actual combustor flow fields. The fuel is H2, and N2 is taken as inert. Temperature in the combustor is on the order of 2000-3000 K and the pressure is of the order of 5 atm. The combustion products consist mainly of H2O and OH. These gases are strong radiators in the infrared. Radiation heating can be significant because of …


A Finite Element Formulation For Aft Fan Duct Acoustic Radiation, Walter Eversman Jan 1997

A Finite Element Formulation For Aft Fan Duct Acoustic Radiation, Walter Eversman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A finite element code has been developed for the prediction of the radiated acoustic field in and around the aft fan duct of a turbofan engine. The acoustic field is modeled based on the assumption that the steady flow in and around the nacelle is irrotational as is the acoustic perturbation. The geometry of the nacelle is axisymmetric, and the acoustic source is harmonic and decomposed into its angular harmonics. The steady flow is computed on the acoustic mesh and provides data for the acoustic calculations. The jet is included in the steady flow potential flow model by separating the …


Numerical Simulations Of Full- Scale Corroded Pipe Tests With Combined Loading, Samit Roy, S. Grigory, M. Smith, M. F. Kanninen, M. Anderson Jan 1997

Numerical Simulations Of Full- Scale Corroded Pipe Tests With Combined Loading, Samit Roy, S. Grigory, M. Smith, M. F. Kanninen, M. Anderson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The ANSI/ASME B31G guideline has been useful to pipeline operators in assessing the integrity of corroded line pipe. Because large safety margins have had to be incorporated, the guidelines can be excessively conservative, which in turn can force costly repairs and replacements that may not actually be necessary. On the other hand, because the current guidelines consider only pressure loading and neglect bending and axial compression, they could give nonconservative failure predictions when combined loading exists. Therefore, a study was initiated to develop a theoretically sound methodology for assessing the integrity of corroded line pipe subjected to combined loading. A …


Integrating Design Into The Sophomore And Junior Level Mechanics Courses, Douglas R. Carroll Jan 1997

Integrating Design Into The Sophomore And Junior Level Mechanics Courses, Douglas R. Carroll

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Engineering schools across the country are developing ways of integrating design into their curriculum, and a question that often arises is how to best integrate design into the sophomore and junior level courses. Freshman design projects or mechanical dissection courses are designed to give the students hands-on experience in conceptual design and construction, with little if any of the mathematical modeling normally used in engineering design. The capstone senior design project is a true engineering design experience, where students draw from their background to conceptualize, analyze, model, refine, and optimize a product to meet design, manufacturing, and life cycle cost …


Eigenvalue And Eigenvector Determination For Damped Gyroscopic Systems, D. P. Malone, Don L. Cronin, Timothy W. Randolph Jan 1997

Eigenvalue And Eigenvector Determination For Damped Gyroscopic Systems, D. P. Malone, Don L. Cronin, Timothy W. Randolph

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.


Bridge Engineering For The Elementary Grades, Douglas R. Carroll Jan 1997

Bridge Engineering For The Elementary Grades, Douglas R. Carroll

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A one-hour presentation was developed to get elementary school students interested in engineering. The presentation begins with the students building six feet long, structurally sound bridge which they can crawl across. A pictorial presentation helps them learn to identify some of the different types of bridges: truss, stone arch, steel arch, concrete girder, cable-stayed, and suspension. They are introduced to the fundamental engineering concepts of tension and compression. These concepts are reinforced by demonstrating that if a tension member is replaced with a chain then the bridge is still strong, but if a compression member is replaced with a chain …


Analysis Of Rockbolt Reinforcement Using Beam-Column Theory, Samit Roy, Anand B. Rajagopalan Jan 1997

Analysis Of Rockbolt Reinforcement Using Beam-Column Theory, Samit Roy, Anand B. Rajagopalan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A simple analytical procedure that applies classical beam-column theory for evaluating passive rock bolt roof reinforcement is presented in this paper. The analytical model is derived from first principles and is capable modelling any number of reinforcing bolts. Each rock bolt is modelled as a linear spring and the model allows for non-uniform bolt spacing. In this study the rock beam is assumed to be isotropic and linearly elastic for the sake of simplicity. However, the analytical model can be extended to include anisotropic rock mass as well as inelastic material behavior. The solution to the couped set of governing …


A System For Collecting Milligram Quantities Of Cloud Condensation Nuclei, Darryl J. Alofs, Donald E. Hagen, Steven D. Medley, Daniel R. White, John L. Schmitt, Allen L. Williams Jan 1997

A System For Collecting Milligram Quantities Of Cloud Condensation Nuclei, Darryl J. Alofs, Donald E. Hagen, Steven D. Medley, Daniel R. White, John L. Schmitt, Allen L. Williams

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An Experimental System to Collect Cloud Condensation Nuclei (CCN) Onto Filters in Amounts Sufficient for Chemical Analysis is Described. This Experimental Apparatus is Designed to Process Ambient Air at a Rate of More Than 1 M3/min. Two Identical Systems Have Been Built. One is Installed in a Laboratory at Rolla, MO. the Other is Installed on an 11 M Long Trailer. the System Isolates Three Size Classes of CCN, Having Mass Median Diameters of 0.27, 0.12, and 0.075 Μm, Respectively, and Mass Collection Rates of 11.5, 1.28, and 0.13 Mg/day, Respectively. the above Sizes and Collection Rates Are Obtained from …