Engineering Commons^™

Vertical And Angular Motion Of A Wing Model In Steady Flow: A Physical And Numerical Experimental Study, Andrew P. Johnston

Opportunities for Undergraduate Research Experience Program (OURE)

The dynamic response of a rigid wing in steady flow mounted on translational and rotational elastic supports is investigated. This study presents both a numerical and a physical experimental arrangement that can be employed to investigate the effect of a wide range of parameters on the response of the wing subjected to steady flow. An interactive computer program, which utilizes the fourth order Runge-Kutta integration scheme to solve the governing differential equations, is discussed. The program output allows for quick visualization of the change in response due to parameter changes. An experimental arrangement that utilizes the new 18" x 18" …

Implementation Of The Articulated Total Body (Atb) Model On An Apollo Workstation, M. F. Laudon

Opportunities for Undergraduate Research Experience Program (OURE)

The Articulated Total Body Model (ATB) is used for predicting gross segmented body response in various dynamic environments. The ATB computer program, originally written by the Department of Transportation as a Crash Victim Simulation (CVS) program, was later modified by the Calspan Corporation and More recently by the Armstrong Aerospace Medical Research Laboratory (AAMRL) to allow for aerodynamic force applications, harness belt capabilities and hyper-ellipsoidal graphical display of the modeled segments. The ATB model has been successfully used to investigate gross human body responses to bodies placed in such complex dynamic environments as high-speed aircraft ejection. This ATB model is …

Some Stability And Control Aspects Of A Variable Pivot Wing Configuration, Paul Vitt

Opportunities for Undergraduate Research Experience Program (OURE)

In supersonic flight, there is a large positive shift in the static margin, which causes extreme positive shifts in longitudinal stability, and is an undesirable characteristic. This paper investigates some of the stability and control aspects of an alternative configuration, that of a variable pivot wing aircraft -- an aircraft with two sets of wings, one set sweeps forward, the other set sweeps rearward. By prescribing a sweep schedule, it is desired to minimize the static margin shift with Mach number. The effects of the two lift elements -- that of mechanical shift of the center of pressure forward with …

Modeling For Supersonic Missile Wing-Body Interference Lift, Howard S. H. Ho

Opportunities for Undergraduate Research Experience Program (OURE)

During the initial phase of a missile design, a quick and simple way of estimating wing-body interference is essential. A simple panel model based on the cross flow over a cylinder is developed to estimate the effect of the body on the wing lift This model produces quick and reasonably accurate results, while little user expertise is needed. This model determines K_WB (upwash interference factor) and K_Φ (sideslip interference factor), and is applicable to infinitely thin delta and clipped delta fins on missiles in supersonic flight. The effects of the fin semivertex angle, span, taper ratio, free stream …

Computer Visualization Of Irrotational Flow Over Bluff And Streamlined Bodies, Nora Okong' O

Opportunities for Undergraduate Research Experience Program (OURE)

Computer programs were developed to visualize irrotational flow over bluff bodies (circular cylinders and half-bodies) and streamlined bodies (elliptical cylinders and airfoils). The method of superposition of flows was used, with stream functions or complex velocity potentials for fundamental flows being added to obtain the flows over the bodies. For the flow over the circular cylinders, half-bodies and elliptical cylinders, the stream function was calculated directly. The flow over the airfoil was obtained by Joukowski mapping of the imaginary part of the complex velocity potential for flow over a circular cylinder.

The programs developed will be valuable learning tools for …

Development Of A Learjet Model 24d For The Umr Flight Simulator, Richard Stigall

Opportunities for Undergraduate Research Experience Program (OURE)

A flight simulator was recently developed at the University of Missouri-Rolla for a single engine aircraft. The need soon arose for a higher performance aircraft. After exploring several possibilities, a Learjet Model 24D was chosen to include the high performance aircraft.

The purpose of this project was to develop a model for the Learjet 24D. This was accomplished by examining the computer code previously written and determining the changes needed. The code for the simulation is located in various subroutines. Each subroutine was analyzed to determine if changes needed to be made. When a modification was needed, appropriate methods were …

Development Of A Large Commercial Transport Model For A Real-Time Digital Flight Simulator, John Francis Winkler

Opportunities for Undergraduate Research Experience Program (OURE)

In order to test the adaptability of the University of Missouri-Rolla's flight simulator to different types of aircraft, a basic mathematical model of a large commercial transport aircraft is developed. The original aircraft model is based on the Cessna 210, and in order to accommodate the drastic differences between the Cessna 210 and the Boeing 747, many changes are made to the simulation code. The aircraft geometric data, stability and control derivatives, and weights data are altered to match those of the 747. Changes are made within the various subroutines to include thrust reversal, spoilers, and a variable incidence horizontal …

Fourier Transform Infrared (Ftir) Spectroscopy Analysis Of Combustion Aerosol, Gary Jacquin

Opportunities for Undergraduate Research Experience Program (OURE)

In conjunction with my co-op program at McDonnell-Douglas, my current OURE project is the analysis of combustion aerosols using Fourier Transform Infrared (FTIR) Spectroscopy. Aerosol science is a very important field as it is concerned with atmospheric chemistry, atmospheric physics, climate, public health, and environmental issues.

In the Cloud and Aerosol Sciences Laboratory (CASL) at UMR, combustion aerosols are generated by an in-house designed torch or burner. The fuels, JP4 and JP5, are provided by McDonnell-Douglas. Some other commercial fuels are also used. The primary objective of my OURE project was to generate and collect combustion aerosols for chemical analysis. …

A Computer Graphics Program For Displaying Water Molecules On A Dn3500 Apollo Workstation, Michael A. Stuller

Opportunities for Undergraduate Research Experience Program (OURE)

A computer graphics program is developed for displaying water molecule configurations on the screen of a DN3500 Apollo workstation. The motivation was to generate a fast display of output from molecular dynamics or Monte Carlo computer simulations. Input to the program consists of a listing of the Cartesian coordinates of the atomic constituents of the molecules. Options in the program include: 1) number of molecules; 2) plot size; 3) atomic radii; 4) superposition of substrate atomic positions; 5) viewing angle; and 6) color-coded and/or numbered atoms. The program is written in Fortran.

Analysis Of Shear Banding In Plane Strain Compression Of A Bimetallic Thermally Softening Viscoplastic Body Containing An Elliptical Void, Z. G. Zhu, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We study plane strain thermomechanical deformations of a prismatic viscoplastic body of square cross-section and deformed at a nominal strain-rate of 5000 s-1. The body has two thin layers placed symmetrically about the horizontal centroidal axis and an elliptical void at the center. The major axis of the void coincides with the vertical centroidal axis and also with the direction of loading. The layer material differs from that of the body in only the value of the yield stress in a quasistatic simple compression test. The yield stress for the layer material is taken to be either one-fifth or five …

Intelligent Control Of A Robotic Arm Using Hierarchical Neural Network Systems, Xavier J. R. Avula, Luis C. Rabelo

Chemical and Biochemical Engineering Faculty Research & Creative Works

Two artificial neural network systems are considered in a hierarchical fashion to plan the trajectory and control of a robotic arm. At the higher level of the hierarchy the neural system consists of four networks: a restricted Coulomb energy network to delineate the robot arm workspace; two standard backpropagation (BP) networks for coordinates transformation; and a fourth network which also uses BP and participates in the trajectory planning by cooperating with other knowledge sources. The control emulation process which is developed using a second neural system at a lower hierarchical level provides the correct sequence of control actions. An example …

Matrix Cracking In Laminated Composites: A Review, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This article presents an overview of the problem of matrix cracking in laminated composite materials. The parameters governing the onset and accumulation of internal damage under several types of loadings are reviewed. The analysis of laminates with matrix cracks can be performed using a shear-lag model, variational, elasticity, finite element or finite difference approaches. Prediction of further cracking is based on either a fracture mechanics approach or a probabilistic failure strength theory. Continuum damage mechanics are used by some investigators to model the behavior of the cracked laminate. Recent developments in this area are summarized here, and suggestions for future …

Decoupled Dynamics For Control And Estimation, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Decoupling of the dynamical equations in polar coordinates is used to develop a control scheme for use in target-intercept problems with passive measurements. By defining a pseudo control variable in the radial coordinate, the radial dynamics is made independent of the transverse dynamics. After solving for the radial control, the transverse control is determined through solutions to a two-point boundary value problem. Numerical results from a six degree-of-freedom simulation which used the decoupled control indicate that it is better than the completely Cartesian coordinate control for most of the cases considered. Decoupled control, though, is obtained iteratively through a two-point …

Hierarchical Neurocontroller Architecture For Intelligent Robotic Manipulation, Xavier J. R. Avula, Luis C. Rabelo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A hierarchical neurocontroller architecture consisting of two artificial neural network systems for the manipulation of a robotic arm is presented. The higher-level neural system participates in the delineation of the robot arm workspace and coordinates transformation and the motion decision-making process. The lower one provides the correct sequence of control actions. The capabilities, including speed, adaptability, and computational efficiency, of the developed architecture are illustrated by an example.

Petri Net Modeling Of A Flexible Assembly Station For Printed Circuit Boards, M. Zhou, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Petri net modeling approaches are presented for a flexible workstation for automatic assembly of printed circuit boards. In order to improve the productivity of such a system, the building of mathematical models is a crucial step. Concentrating on the operational aspects, the authors construct ordinary and temporal Petri net models for the AT&T FWS-200 physical flexible workstation. Three outcomes follow from such models. First, designers can have a better understanding of concurrency, synchronization, mutual exclusion, and sequential relations involved in the system control from the graphical representations of Petri nets. Second, the performance analysis of system operations under different settings …

Impact On Laminated Composite Materials, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laminated composite materials are used extensively in aerospace and other applications. With their high specific modulus, high specific strength, and the capability of being tailored for a specific application, these materials offer definite advantages compared to more traditional materials. However, their behavior under impact is a concern, since impacts do occur during manufacture, normal operations, or maintenance. The situation is critical for impacts which induce significant internal damage, undetectable by visual inspection, that cause large drops in the strength and stability of the structure. Impact dynamics, including the motion of both the impactor and the target and the force developed …

Dynamic Adiabatic Shear Band Development In A Bimetallic Body Containing A Void, R. C. Batra, Z. G. Zhu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We study the problem of the initiation and subsequent growth of a shear band in a thermally softening viscoplaslic prismatic body of square cross-section and containing two symmetrically placed thin layers of a different viscoplastic material and an elliptical void at the center. The yield stress of the material of the thin layer in a quasistatic simple compression test is taken to be either five times or one-fifth that of the matrix material. The body is deformed in plane strain compression at a nominal strain rate of 5.000 s '. These deformations are assumed to be symmetrical about the centroidal …