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Articles 1 - 10 of 10
Full-Text Articles in Mechanical Engineering
Intercomparison Between Commercial Condensation Nucleus Counters And An Alternating Temperature Gradient Cloud Chamber, Darryl J. Alofs, C. K. Lutrus, Donald E. Hagen
Intercomparison Between Commercial Condensation Nucleus Counters And An Alternating Temperature Gradient Cloud Chamber, Darryl J. Alofs, C. K. Lutrus, Donald E. Hagen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Three Commercial CNC Counters (TSI Models 3010, 3022A, and 3025A) Are Compared with an Alternating Temperature Gradient Cloud Chamber (ALGR). Electrically Size Classified Aerosols of Sodium Chloride and Silver Are Used. Diffusional Losses within the ALGR Are Much Larger Than for the TSI Instruments: Therefore the ALGR Concentrations Are Corrected for Internal Diffusional Losses, But the TSI Instruments Are Not. the Particle Size Range Tested is 4–90 Nm. for Sodium Chloride, the TSI Concentrations Agreed Fairly Well with the Corrected ALGR at Larger Sizes, and Were Below the Corrected ALGR at Smaller Sizes. the Electrical Aerosol Classifier (EAC) Setting at …
Fuzzy Logic In Restructurable Flight Control Systems, S. N. Balakrishnan, H. S. Ho
Fuzzy Logic In Restructurable Flight Control Systems, S. N. Balakrishnan, H. S. Ho
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, a fuzzy logic controller (FLC) is proposed for restructurable flight control systems. The role of the FLC is to stabilize the aircraft upon a fault occurrence. The FLC derives pitch/roll/yaw controls from a generic knowledge base characterized by 49 if-then rules. A linearized model representative of a modern jet fighter provides the basis for the numerical simulation. Simulated faults include various degrees of surface loss at the right stabilator, combined with reduced ailerons and rudder control power. The FLC accomplishes the stabilization task under test conditions without any knowledge of the system parameters. The numerical results demonstrate …
A New Neural Architecture For Homing Missile Guidance, S. N. Balakrishnan, Victor Biega
A New Neural Architecture For Homing Missile Guidance, S. N. Balakrishnan, Victor Biega
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We present a new neural architecture which imbeds dynamic programming solutions to solve optimal target-intercept problems. They provide feedback guidance solutions, which are optimal with any initial conditions and time-to-go, for a 2D scenario. The method discussed in this study determines an optimal control law for a system by successively adapting two networks - an action and a critic network. This method determines the control law for an entire range of initial conditions; it simultaneously determines and adapts the neural networks to the optimal control policy for both linear and nonlinear systems. In addition, it is important to know that …
Adaptive Critic Based Neural Networks For Control (Low Order System Applications), S. N. Balakrishnan, Victor Biega
Adaptive Critic Based Neural Networks For Control (Low Order System Applications), S. N. Balakrishnan, Victor Biega
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Dynamic programming is an exact method of determining optimal control for a discretized system. Unfortunately, for nonlinear systems the computations necessary with this method become prohibitive. This study investigates the use of adaptive neural networks that utilize dynamic programming methodology to develop near optimal control laws. First, a one dimensional infinite horizon problem is examined. Problems involving cost functions with final state constraints are considered for one dimensional linear and nonlinear systems. A two dimensional linear problem is also investigated. In addition to these examples, an example of the corrective capabilities of critics is shown. Synthesis of the networks in …
Hamiltonian Based Adaptive Critics For Aircraft Control, S. N. Balakrishnan, Jie Shen
Hamiltonian Based Adaptive Critics For Aircraft Control, S. N. Balakrishnan, Jie Shen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Aircraft designs are becoming more complex in order to either operate more efficiently as in the commercial sector or to push the performance envelopes as in the military sector. An interesting outcome of this scenario is that `control'' has come to play an important role in helping realize these objectives. Increasingly, control is becoming an integral part of an aircraft design rather than an afterthought. More effective and efficient control of an aircraft is certain to lead to improved performance at a lower cost
Thermal Contact Conductance Of Ceramic Substrate Junctions, K. C. Chung, H. K. Benson, John W. Sheffield
Thermal Contact Conductance Of Ceramic Substrate Junctions, K. C. Chung, H. K. Benson, John W. Sheffield
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
On A Method For Obtaining Approximate Solutions To Sturm-Liouville Problems, Serge Abrate
On A Method For Obtaining Approximate Solutions To Sturm-Liouville Problems, Serge Abrate
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A method presented recently to find approximate solutions to a Sturm-Liouville problem is shown to be a special case of a classical weighted residual method. The choice of approximation functions and convergence of the method are also examined. © 1995 American Mathematical Society.
Vibration Of Point-Supported Rectangular Composite Plates, Serge Abrate
Vibration Of Point-Supported Rectangular Composite Plates, Serge Abrate
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A general approach is presented to study the free vibrations of rectangular symmetrically laminated composite plates with point supports by using the Rayleigh-Ritz method and the Lagrange multiplier technique for enforcing the zero displacement constraints at the support locations. Polynomial approximation functions are used, and the constitutive relationships are written in terms of four lamination parameters. With these lamination parameters, the number of design variables is reduced to a minimum, which is useful for design optimization purposes, while all symmetric lay-ups are considered. This paper illustrates how the lamination parameters can be used for optimal design of vibrating plates. Results …
Improved Finite Element Modeling Of The Turbofan Engine Inlet Radiation Problem, I. Danda Roy, Walter Eversman
Improved Finite Element Modeling Of The Turbofan Engine Inlet Radiation Problem, I. Danda Roy, Walter Eversman
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Improvements have been made in the finite element model of the acoustic radiated field from a turbofan engine inlet in the presence of a mean flow. The problem of acoustic radiation from a turbofan engine inlet is difficult to model numerically because of the large domain and high frequencies involved. A numerical model with conventional finite elements in the near field and wave envelope elements in the far field has been constructed. By employing an irrotational mean flow assumption, both the mean flow and the acoustic perturbation problem have been posed in an axisymmetric formulation in terms of the velocity …
On The Use Of Students For Developing Engineering Laboratories, Bopaya Bidanda, Richard E. Billo
On The Use Of Students For Developing Engineering Laboratories, Bopaya Bidanda, Richard E. Billo
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper describes a unique and innovative approach that solved the dual problem of starting up a new engineering instructional laboratory in a timely manner, and for teaching engineering students advanced skills in Automatic Data Collection. Students enrolled in a special pilot course were used to develop and startup an Automatic Data Collection laboratory. These students were assigned individual Automatic Data Collection technologies of interest and given total responsibility for the successful startup of the laboratory. The organization and structure of the course modeled the typical team oriented project development efforts in industry. Feedback from students showed the course to …