Open Access. Powered by Scholars. Published by Universities.®

Aerospace Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 901 - 930 of 1158

Full-Text Articles in Aerospace Engineering

Proper Orthogonal Decomposition Based Feedback Optimal Control Synthesis Of Distributed Parameter Systems Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan Jan 2002

Proper Orthogonal Decomposition Based Feedback Optimal Control Synthesis Of Distributed Parameter Systems Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new method for optimal control design of distributed parameter systems is presented in this paper. The concept of proper orthogonal decomposition is used for the model reduction of distributed parameter systems to form a reduced order lumped parameter problem. The optimal control problem is then solved in the time domain, in a state feedback sense, following the philosophy of ''adaptive critic'' neural networks. The control solution is then mapped back to the spatial domain using the same basis functions. Numerical simulation results are presented for a linear and nonlinear one-dimensional heat equation problem in an infinite time regulator framework.

Go to article

A New Optimal Nonlinear Control Method And Its Application To Missile Guidance Law Design, Ming Xin, S. N. Balakrishnan Jan 2002

A New Optimal Nonlinear Control Method And Its Application To Missile Guidance Law Design, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear control synthesis technique (q-D approximation) is discussed. By adding perturbations to the cost function this approach achieves a suboptimal solution to the Hamilton-Jacobi- Bellman (HJB) equation. By manipulating the perturbation terms both asymptotic stability and optimality properties are obtained. An application to the design of missile guidance law is presented and is compared with a similar technique (State Dependent Riccati Equation technique) used in problems of this class. © 2002 by the author(s).

Go to article

State Dependent Riccati Equation Based Spacecraft Attitude Control, Ming Xin, S. N. Balakrishnan Jan 2002

State Dependent Riccati Equation Based Spacecraft Attitude Control, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a new optimal control approach to the robust spacecraft attitude control in the framework of State Dependent Riccati Equation (SDRE) technique. To treat this highly nonlinear control system, we formulate it as a nonlinear optimal regulator problem. SDRE technique was well applied to this class of attitude control problem. We also synthesize a neural network based extra controller to achieve the robustness in the presence of the parameter uncertainties. A general spacecraft attitude regulation problem was studied to show the effectiveness of SDRE approach and robust extra control design. © 2002. Published by the American Institute of Aeronautics …

Go to article

Accuracy And Efficiency In Fem Modeling Of Turbofan Acoustic Radiation, Eivind Listerud, Walter Eversman Jan 2002

Accuracy And Efficiency In Fem Modeling Of Turbofan Acoustic Radiation, Eivind Listerud, Walter Eversman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It is shown that there is an increase in efficiency of acoustic radiation finite element modeling with the incorporation of cubic rather than quadratic serendipity elements. Cubic serendipity elements produce a given level of accuracy for acoustic pressure using a coarser mesh than required using quadratic elements, thus decreasing the CPU time needed for accurate modeling. These elements have been applied to the near field inlet and aft acoustic radiation models for a turbofan engine with the result of considerable reduction in the dimensionality of the problem without sacrificing accuracy. Visual observations of the gain in computational efficiency is supported …

Go to article

Cfd Simulations Of Critical Components In Fuel Filling Systems, R. Banerjee, X. Bai, D. Pugh, Kakkattukuzhy M. Isaac, D. Klein, J. Edson, W. Breig, L. Oliver Jan 2002

Cfd Simulations Of Critical Components In Fuel Filling Systems, R. Banerjee, X. Bai, D. Pugh, Kakkattukuzhy M. Isaac, D. Klein, J. Edson, W. Breig, L. Oliver

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A comprehensive study is reported on the dynamics of critical components in the refueling process for passenger cars and light trucks. Nozzle, filler pipe, recirculation tube, tank, and canister are investigated. CFD simulations are conducted for flow rates of 4 liters/min (lpm) to 80 lpm for gasoline and up to 120 lpm for diesel fuel. Tank pressure, identified as a critical parameter controlling flow performance, is measured and utilized as a boundary condition. Flow simulation in a carbon canister, accomplished by treating the adsorbing carbon as a porous medium, indicates pressure drops which are in good agreement with published experimental …

Go to article

Proper Orthogonal Decomposition Based Optimal Control Design Of Heat Equation With Discrete Actuators Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan Jan 2002

Proper Orthogonal Decomposition Based Optimal Control Design Of Heat Equation With Discrete Actuators Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new method is presented for the optimal control design of one-dimensional heat equation with the actuators being concentrated at discrete points in the spatial domain. This systematic methodology incorporates the advanced concept of proper orthogonal decomposition for the model reduction of distributed parameter systems. After deigning a set of problem-oriented basis functions an analogous optimal control problem in the lumped domain is formulated. The optimal control problem is then solved in the time domain, in a state feedback sense, following the philosophy of adaptive critic neural networks. The control solution is then mapped back to the spatial domain using …

Go to article

A Quantitative Similarity Metric For Design-By-Analogy, Daniel A. Mcadams, Kristin L. Wood Jan 2002

A Quantitative Similarity Metric For Design-By-Analogy, Daniel A. Mcadams, Kristin L. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

During the design and development of new products, design engineers use many techniques to generate and define new and "good" concepts. Inherent in this search for solutions is the conscious and unconscious reliance on prior experience and knowledge, or design-by-analogy. In this paper, a quantitative metric for design-by-analogy is developed. This metric is based on the functional similarity of products. By using this product-similarity metric, designers are able to formalize and quantify design-by-analogy techniques during concept and layout design. The methods, as developed in this paper, allow a designer with limited experience to develop sophisticated solutions that enhance the overall …

Go to article

Forensic Investigation Of Failed Mast Arms Of Traffic Signal Supported Structures, Genda Chen, Michael G. Barker, D. Scott Mackenzie, Christopher W. Ramsay, Joe Alderson, Lokeswarappa R. Dharani, Jiaqing Yu Jan 2002

Forensic Investigation Of Failed Mast Arms Of Traffic Signal Supported Structures, Genda Chen, Michael G. Barker, D. Scott Mackenzie, Christopher W. Ramsay, Joe Alderson, Lokeswarappa R. Dharani, Jiaqing Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In Missouri, 11 traffic signal mast arms fractured at the arm-post weld connection in 7 years. To reduce this fatigue failure, the Missouri Department of Transportation developed a fatigue-resistant weld profile that increases the weld leg and reduces the slope of the weld at the toe. This study investigated causes of the failed arms, compared performance of new and old weld profiles, and suggested retrofitting measures for further investigation. The scope included a metallurgical investigation of one failed field mast arm, laboratory fatigue testing of five prototype mast arms (two new and three old profiles), and laboratory failure analysis of …

Go to article

Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan Jan 2002

Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan

Electrical and Computer Engineering Faculty Research & Creative Works

A multilayer neural network (NN) controller in discrete-time is designed to deliver a desired tracking performance for a class of nonlinear systems with input deadzones. This multilayer NN controller has an adaptive critic NN architecture with two NNs for compensating the deadzone nonlinearity and a third NN for approximating the dynamics of the nonlinear system. A reinforcement learning scheme in discrete-time is proposed for the adaptive critic NN deadzone compensator, where the learning is performed based on a certain performance measure, which is supplied from a critic. The adaptive generating NN rejects the errors induced by the deadzone whereas a …

Go to article

A New Method For Suboptimal Control Of A Class Of Nonlinear Systems, Ming Xin, S. N. Balakrishnan Jan 2002

A New Method For Suboptimal Control Of A Class Of Nonlinear Systems, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear control synthesis technique (θ - D approximation) is presented. This approach achieves suboptimal solutions to nonlinear optimal control problems in the sense that it solves the Hamilton-Jacobi-Bellman (HJB) equation approximately by adding perturbations to the cost function. By manipulating the perturbation terms both semi-globally asymptotic stability and suboptimality properties can be obtained. The convergence and stability proofs are given. This method overcomes the large control for large initial states problem that occurs in some other Taylor expansion based methods. It does not need time-consuming online computations like the state dependent Riccati equation (SDRE) technique. …

Go to article

World Wide Web Resources For Materials Science, Serge Abrate Dec 2001

World Wide Web Resources For Materials Science, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The internet makes technical information readily available in ways that were unthinkable a few years ago. This article shows how the World Wide Web (the web) can be used in a Materials Science class to enrich the educational process. Strategies for finding and evaluating information and are discussed. © 2002 Wiley Periodicals, Inc.

Go to article

Ingaasnsb/Gaas Quantum Wells For 1.55 Μm Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, L. F. Mei, W. I. Wang Jun 2001

Ingaasnsb/Gaas Quantum Wells For 1.55 Μm Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, L. F. Mei, W. I. Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

InGaAsNSb/GaAs quantum wells (QWs) were grown by solid-source molecular-beam epitaxy using a N2 radio frequency plasma source. The effect of adding Sb during growth of InGaAsN/GaAs QWs was studied. X-ray diffraction, reflection high-energy electron diffraction and transmission electron microscopy studies indicate that Sb suppresses the three-dimensional growth and improves the interface of the QWs. X-ray diffraction and secondary ion mass spectroscopy analysis show that Sb gets incorporated into the quantum well, which becomes a quinternary compound that was previously unexplored. The introduction of Sb during growth of InGaAsN/GaAs QWs significantly enhances the optical properties of the QWs. 1.53 /spl …

Go to article

Robust State Dependent Riccati Equation Based Guidance Laws, S. N. Balakrishnan, Ming Xin Jan 2001

Robust State Dependent Riccati Equation Based Guidance Laws, S. N. Balakrishnan, Ming Xin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A robust state dependent Riccati equation based guidance/control is investigated in this study. In order to have a better design tool in terms of required interceptor accelerations, the target intercept geometry is formulated in a set of polar coordinates. With this formulation, we formulate a cost function with state dependent weights. In this study, we investigate the effects of such cost functions on the levels of interceptor accelerations. We also synthesize a neural network based extra controller to achieve the robustness in the presence of the target acceleration. In this manner, we will not need target acceleration estimation explicitly in …

Go to article

A Numerical Study Of Automotive Gas Tank Filler Pipe Two Phase Flow, R. Banerjee, Kakkattukuzhy M. Isaac, L. Oliver, W. Breig Jan 2001

A Numerical Study Of Automotive Gas Tank Filler Pipe Two Phase Flow, R. Banerjee, Kakkattukuzhy M. Isaac, L. Oliver, W. Breig

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Automotive refueling is gaining greater importance because fuel vapors released during refueling are believed to increase ozone levels in urban areas. As a step towards On-Board Refueling Vapor Recovery (ORVR) designs, vapor generation and transport during refueling needs to be understood to develop recovery techniques. The objective of the present study is to understand the fluid flow inside the automotive gas tank filler pipe using commercially available Computational Fluid Dynamics (CFD) software. This effort is expected to yield detailed flow field information, including air entrainment. The phenomena of well-back, the process of fuel flooding the filler pipe and flowing backwards …

Go to article

Detection And Classification Of Impact-Induced Damage In Composite Plates Using Neural Networks, Rohit Dua, Steve Eugene Watkins, Donald C. Wunsch, K. Chandrashekhara, Farhad Akhavan Jan 2001

Detection And Classification Of Impact-Induced Damage In Composite Plates Using Neural Networks, Rohit Dua, Steve Eugene Watkins, Donald C. Wunsch, K. Chandrashekhara, Farhad Akhavan

Electrical and Computer Engineering Faculty Research & Creative Works

Artificial neutral networks (ANN) can be used as an online health monitoring systems (involving damage assessment, fatigue monitoring and delamination detection) for composite structures owing to their inherent fast computing speeds, parallel processing and ability to learn and adapt to the experimental data. The amount of impact-induced strain on a composite structure can be found using strain sensors attached to composite structures. Prior work has shown that strain-based ANN can characterize impact energy on composite plates and that strain signatures can be associated with damage types and severity. This paper reports the extension of this approach for damage classification using …

Go to article

High Precision Solder Droplet Printing Technology: Principle And Applications, Qingbin Liu, M. Orme, Ming-Chuan Leu Jan 2001

High Precision Solder Droplet Printing Technology: Principle And Applications, Qingbin Liu, M. Orme, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Solder droplet printing technology, which is low-cost, noncontact, flexible, data-driven, and environmentally friendly, has emerged as an enabling technology for precisely placing fine solder deposits on a variety of small substrates. It is suitable for a variety of applications including direct chip attach site preparation, 3D substrates, fine line interconnect, substrate via fill, optoelectronics and many others. It enables manufacturing techniques that are impossible or unfeasible with current technology, such as localized replacement of solder on board, depositing solder in different thicknesses on the same board, or using more than one type of solder on the same board. This makes …

Go to article

Robust State Dependent Riccati Equation Based Robot Manipulator Control, Ming Xin, S. N. Balakrishnan, Zhongwu Huang Jan 2001

Robust State Dependent Riccati Equation Based Robot Manipulator Control, Ming Xin, S. N. Balakrishnan, Zhongwu Huang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a new optimal control approach to robust control of robot manipulators in the framework of state dependent Riccati equation (SDRE) technique. To treat this highly nonlinear control system, we formulate it as a nonlinear optimal regulator problem. SDRE technique was used to synthesize an optimal controller to this class of robot control problem. We also synthesize a neural network based extra controller to achieve the robustness in the presence of the parameter uncertainties. A typical two-link robot position control problem was studied to show the effectiveness of SDRE approach and robust extra control design to robotic application.

Go to article

Re-Examination Of The Crypto-Steady Pressure-Exchanger (Virtual Turbomachine), T. Scott, David W. Riggins Jan 2001

Re-Examination Of The Crypto-Steady Pressure-Exchanger (Virtual Turbomachine), T. Scott, David W. Riggins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A crypto-steady pressure-exchanger (rotating center body ejecting fluid in a supersonic flow field) is investigated based on fundamental fluid dynamic principles. The results are then compared to computational fluid dynamic (CFD) simulations of a simplified device. On the basis of this comparison the device studied is correctly classified as an unsteady ejector instead of a type of turbomachinery. Entropy gains (total pressure losses) associated with the complex fluid-fluid and fluid-center body interactions are shown to be greater than total pressure gains due to work addition. Compared to a steady ejector, the virtual turbomachine shows increased entrainment (mixing) of the main …

Go to article

Robust Adaptive Critic Based Neurocontrollers For Missiles With Model Uncertainties, Zhongwu Huang, S. N. Balakrishnan Jan 2001

Robust Adaptive Critic Based Neurocontrollers For Missiles With Model Uncertainties, Zhongwu Huang, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Lyapunov theory-based controller is proposed in this paper for robustness against model uncertainties in the control of a missile. The controller design consists of two parts; in the first phase, an optimal nonlinear controller is designed with neural networks for tracking. This is based on the adaptive critic method that consists of one neural network called the supervisor or critic and a second network called an action network or a controller. Each network is trained through the output of the other network and equations related to optimal control. When their outputs are mutually consistent, the controller network output is …

Go to article

Fatigue Assessment Of Traffic Signal Mast Arms Based On Field Test Data Under Natural Wind Gusts, Genda Chen, Jingning Wu, Jiaqing Yu, Lokeswarappa R. Dharani, Michael G. Barker Jan 2001

Fatigue Assessment Of Traffic Signal Mast Arms Based On Field Test Data Under Natural Wind Gusts, Genda Chen, Jingning Wu, Jiaqing Yu, Lokeswarappa R. Dharani, Michael G. Barker

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In recent years, several states including Missouri, Wyoming, California, and Texas experienced fracture failures of traffic signal mast arms. Almost all the failures are associated with the propagation of defects or cracks. It is therefore imperative to evaluate existing mast arms using a simple yet accurate procedure. A statistical methodology is proposed to predict the fatigue life of signal mast arm structures on the basis of field-measured strain data. The annual occurrence of various stress levels is determined using the historical wind speed data in the vicinity of a mast arm structure and the strain readings of the structure under …

Go to article

Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu Jan 2001

Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

There are many methods used at present to apply solder to wafers, ceramics, laminate and flex circuit boards, and other substrates. Among these, high-precision solder droplet printing technology, which is noncontact, data driven, flexible and environmentally friendly, is a key enabling technology. This technology selectively deposits solder droplets only where required, and therefore needs no mask or secondary resist removal, uses materials more efficiently and creates less waste than other methods. Currently, continuous droplet formation from capillary streams is mainly achieved by application of the well-known Rayleigh instability in which a sinusoidal disturbance is applied to the stream, resulting in …

Go to article

Adaptive Critic Based Neuro-Observer, Xin Liu, S. N. Balakrishnan Jan 2001

Adaptive Critic Based Neuro-Observer, Xin Liu, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new Neural Network (NN) based observer design method for nonlinear systems represented by nonlinear dynamics and linear/nonlinear measurement is proposed in this paper. In this new approach, as the first step, the observer design problem is changed into a "controller" design problem by establishing the error dynamics, and then the Adaptive Critic (AC) based approach is applied on this error dynamics to design a 'controller', such that the errors are driven to zero. The resulting observer has inherent robustness from the AC based design approach. Some simulations are presented to illustrate the effectiveness of this approach.

Go to article

An Optimal Control Based Treatment Strategy For Parturient Paresis Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan Jan 2001

An Optimal Control Based Treatment Strategy For Parturient Paresis Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An optimal online feedback treatment strategy is developed for the parturient paresis of cows, based on nonlinear optimal control theory. A limitation in the development of an existing mathematical model for calcium homeostasis is addressed and the model is extended to incorporate control inputs. An optimal feedback controller is synthesized for the nonlinear system using neural networks. Though the main aim of this paper is to solve the biomedical control problem, the methodology presented in this paper is a general computational tool, which can be applied to solve a fairly general class nonlinear optimal control problems.

Go to article

High-Temperature Characteristics Of 1.3 Μm Ingaasn:Sb/Gaas Multiple-Quantum-Well Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, M. J. Jurkovic, W. I. Wang Feb 2000

High-Temperature Characteristics Of 1.3 Μm Ingaasn:Sb/Gaas Multiple-Quantum-Well Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, M. J. Jurkovic, W. I. Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

1.3 μm InGaAsN:Sb/GaAs multiple-quantum-well laser diodes have been grown by solid-source molecular-beam epitaxy using Sb as a surfactant. A low threshold of 1.1 kA/cm² was achieved for broad-area laser diodes under pulsed operation at room temperature. High-temperature device characterization revealed characteristic temperatures (T₀) of 92 and 54 K for operating temperatures below and above 75°C, respectively, as well as a lasing-wavelength temperature dependence of 0.36 nm/°C.

Go to article

Editorial, Ahmed Noor, Victor Birman Jan 2000

Editorial, Ahmed Noor, Victor Birman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Go to article

Experimental Characterization Of Hygrothermal And Aging Effects In Textile Composites, Lokeswarappa R. Dharani, Samit Roy, V. Gupta, Weiqun Xu, N. Dixon Jan 2000

Experimental Characterization Of Hygrothermal And Aging Effects In Textile Composites, Lokeswarappa R. Dharani, Samit Roy, V. Gupta, Weiqun Xu, N. Dixon

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper summarizes the hygrothermal and physical aging tests that were conducted on AS4/PR500 5HS textile composite laminates. The objectives of the hygrothermal tests were to determine the diffusivity and maximum moisture content of the laminate. Three temperatures and three relative humidity levels (RH) were used in combination to create seven test conditions. In addition, three stress levels and three damage levels were imposed to examine the combined effects of stress and damage on moisture absorption. Short-term creep tests were performed on neat resin at different test temperatures to characterize physical aging of the resin matrix. In addition, creep and …

Go to article

Midcourse Guidance Law With Neural Networks, Dongchen Han, S. N. Balakrishnan Jan 2000

Midcourse Guidance Law With Neural Networks, Dongchen Han, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A neural network-based synthesis of an optimal midcourse guidance law is presented in this study. We use a set of two-neural networks; the first network called 'a critic' outputs the Lagrange's multipliers arising in an optimal control formulation and second network called 'an action network' outputs the optimal guidance/control. In this so-called 'adaptive critic' approach, the inputs to the networks are the current values of the states. This approach needs no external training. System equations, optimality conditions and the costate equations are used in conjunction with the network outputs to provide the targets for the neural networks. When the critic …

Go to article

Infinite Time Optimal Neuro Control For Distributed Parameter Systems, S. N. Balakrishnan, Radhakant Padhi Jan 2000

Infinite Time Optimal Neuro Control For Distributed Parameter Systems, S. N. Balakrishnan, Radhakant Padhi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The conventional dynamic programming methodology for the solution of optimal control, despite having many desirable features, is severely restricted by its computational requirements. However, in recent times, an alternate formulation, known as the adaptive-critic synthesis, has given it a new perspective. In this paper, we have attempted to use the philosophy of adaptive-critic design to the optimal control of distributed parameter systems. An important contribution of this study is the derivation of the necessary conditions of optimality for distributed parameter systems, described in discrete domain, following the principle of approximate dynamic programming. Then the derived necessary conditions of optimality are …

Go to article

Carryover For Hypersonic '+' And 'X' Configuration Delta Fin Missiles, Harlan F. Nelson Jan 2000

Carryover For Hypersonic '+' And 'X' Configuration Delta Fin Missiles, Harlan F. Nelson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Zonal Euler Solver code (ZEUS) is used to predict hypersonic missile flow fields and to determine the carryover factors for the effect of the body on wing lift, Kw(B), and for the effect of the wing on body lift, KB(w). Results are presented for Mach 4, 6, 8, and 10 at an angle of attack of 2 deg. The missile has a conical nose and a cylindrical fuselage with a 1-degree flair angle. Both 'x' and '+' fin configurations are considered. Results are given for 20 and 30 deg semi vertex angles as a function of fur span to …

Go to article

Tuning Parameter Tolerance Design: Foundations, Methods, And Measures, Daniel A. Mcadams, Kristin L. Wood Jan 2000

Tuning Parameter Tolerance Design: Foundations, Methods, And Measures, Daniel A. Mcadams, Kristin L. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a novel technique is presented to solve tolerance design problems. To achieve the desired performance tolerance, the technique uses a subtle, but significant, change in the design: the addition of a tuning parameter in place of an increase in component precision. Statistical models are used to develop a framework for the tuning parameter design method. Also developed is a new, dimensionless design metric which ranks candidate tuning parameters. A step-by-step method is developed for the application of tuning parameters using this metric. The step-by-step tuning parameter design method is applied to a heavy-duty manual stapler as a …

Go to article

First Prev Next Last