Stabilization and shock-capturing parameters introduced recently for the StreamlineUpwind/Petrov-Galerkin (SUPG) formulation of compressible flows based on conservation variables are assessed in test computations with inviscid supersonic flows and different types of finite element meshes. The new shock-capturing parameters, categorized as "YZbeta Shock-Capturing" in this paper, are compared to earlier parameters derived based on the entropy variables. In addition to being much simpler, the new shock-capturing parameters yield better shock quality the test computations, with more substantial improvements seen for triangular elements. Numerical experiments with inviscid supersonic flows around cylinders and spheres are carried out to evaluate the stabilization and shock-capturing parameters introduced recently for the Streamline-Upwind/Petrov-Galerkin (SUPG) formulation of compressible flows based on conservation variables. The tests with the cylinders are carried out for both structured and unstructured meshes. The new shock-capturing parameters; which we call "YZbeta Shock-Capturing", are compared to earlier SUPG parameters derived based on the entropy variables. In addition to being much simpler, the new shock-capturing parameters yield better shock quality in the test computations, with more substantial improvements seen for unstructured meshes with triangular and tetrahedral elements. Furthermore, the results obtained with YZbeta Shock-Capturing compare very favorably to those obtained with the well established OVERFLOW code.

Laminates composed of alternating layers of metal and fiber reinforced polymers (FRP's) exhibit a number of properties, which are preferable to either metals or FRP's alone, making them attractive materials for a number of industries, particularly aerospace. A number of questions persist, however, before these new composites can be widely accepted and utilized; one of which is their response to impact, which may occur over a wide range of velocities. Numerical methods, especially the FEA method, have been widely used to simulate the impact response because they can reduce the cost and save time comparing with the experiment. In this work, a continuum damage based model (CDM) is developed and implemented into FEA commercial software ABAQUS. Using a rate-dependent plasticity model for the constitutive behavior of Aluminum and the CDM for the behavior of fiberglass laminates, the dynamic penetration is simulated using ABAQUS. Force vs. displacement results compare well with those obtained from the experiments. In addition, the computed damage region is in close agreement with that seen in sectioned specimens of the tested material. Simulations are also performed for ballistic experiments conducted on 150mm x 150mm clamped panels of the same laminates. Ballistic experiments involve both the local penetration response as well as the global deformation behavior, particularly at velocities near the ballistic limit, where significant flexural deformation takes place. Results from the simulation agree well with the ballistic experiment results. Given the validity of the modeling approach, the high velocity impact response of the other metal/fiber systems can be examined minimizing the need for trial and error fabrication.

Piezoelectric materials offer an alternative method for active control of aeroelastic oscillations, that is potentially cheaper, lighter, and more effective than conventional control methods. In this thesis, the aeroelastic oscillations of a delta wing under the combined effects of unsteady, supersonic aerodynamic loading and bonded piezoelectric strips are studied. / The delta wing is modelled as a cantilevered triangular plate undergoing small transverse oscillations. Using the structural model developed here, the natural frequencies of the wing are obtained. A hybrid analytical-numerical method is developed for the unsteady supersonic aerodynamics of the wing, in order to determine the unsteady pressure distribution and the generalized aerodynamic forces on the wing. It is shown that the method adopted here to obtain the pressure distribution is more accurate than the analytical method based on frequency expansion, and computationally were efficient than the numerical methods using the Mach Box approach. Finally, in the presence of bonded piezoelectric strips, the transient and dynamic responses of the wing are studied without and with aerodynamic loading, respectively. / It is found that with particular combinations of voltages and the number of piezoelectric strips, the amplitude of the aeroelastic oscillations can be reduced. These required combinations change as the periodic frequency of wing oscillation is varied. Additionally, the piezoelectric actuators aligned with the span are more effective than the chord-aligned piezoelectric actuators, which produce little or no reduction in the oscillations. It is further found that even a small number of strips can effectively reduce the magnitude of the oscillations.

A general-purpose constraint satisfaction algorithm has been developed as part of the FLITE system for flight simulator tuning. It offers an improved time complexity of O($a sp{n}$), as compared with O($n sp{2}$(a + 1)$ sp{n}$) in (1). There are two steps to solving a constraint network. In the first step, all values which can never appear as part of any solution are removed from the domain of their corresponding variable. Smart starting points are used to jump to a branch of the tree which is more likely to hold the path being sought. Then backtracking is used to find all sets of consistent variable/value labelings which describe the solutions. Dynamic variable swapping is used to rearrange the order in which variables are bound, so as to reduce the size of the search tree. The algorithm works efficiently with sparse and fully connected constraint networks.

Based on the barycentric vector and direct path approaches, the kinematics of a multiple arm space robotic system is developed, and the differences between the two formulations are discussed. Applying the general Lagrangian formulation, a concise explicit model of the system dynamics is derived, and the specific characteristics of space robotic systems as compared to fixed-base manipulators are discussed. / Coordination between a spacecraft and its multiple end-effectors, based on planned trajectories, is investigated in capturing a moving space object. Two model-based control algorithms, based on an Euler angle and an Euler parameter description of the orientation, are proposed as well as a transpose Jacobian controller. Simulation results are presented to evaluate the developed controllers and the planning strategy, in both planar and three-dimensional maneuvers. / To control coordinated motions of space robotic systems, a new Modified Transpose Jacobian (MTJ) controller is presented which yields an improved performance over the standard algorithm. Simulation results show that the performance of the MTJ law is comparable to that of model-based algorithms, even though it requires a reduced computational effort. / To manipulate a captured object by multiple manipulators, a new Multiple Impedance Control (MIC) algorithm is developed which enforces an identical controlled impedance on each participating manipulator, on the manipulated object, and (in space) on the free-flying spacecraft. The similarities and differences between the developed MiC law and other force/impedance controllers are investigated, and simulation results are presented.

Analytical methods solving for the separated flow over delta wings have been based on the slender-body theory, which applies for wing geometries of small aspect ratio. The slender-body solutions are independent of the Mach number, and therefore, for supersonic flow, cannot appropriately take into account the directional propagation of disturbances. The slender-body model is attractively simple of the pressure distribution and lift prediction, but in the supersonic regime it can lead to large errors when the wing geometry is not very slender with respect to the Mach cone. / In the treatment of attached flow over arbitrary wing-body combinations in supersonic flow regime, the method of Velocity Singularities based on conical motion provides a more accurate alternative over slender-body theory by considering the appropriate boundary condition of flow disturbances outside the wings. / This thesis presents an extension of the method of Velocity Singularities for the analysis of the separated flow over thin delta wings.

The springback phenomenon was studied by a series of draw-bend tests. These tests were done by varying the blankholding pressure with different lubrication conditions, and with different transverse anisotropy directions. The purpose is to find the forming loads, the thickness changes and the springback angles. It has been found that the springback angle after unloading depends on the amount of blankholding pressure, the material properties, and the tool geometry. Increasing the blankholding pressure almost eliminates the springback if the tensile stress caused by the blankholding pressure reaches the yield in the material. To compliment the experiments, a theoretical model has been developed by calculating the tensile strain developed from applying the blankholding pressure. This strain then was considered in finding the total bending moment.

The essence of this work consists of developing a robust algorithm for the estimation of Lyapunov exponents and complex exponents from an observed time series. These characteristic exponents are representative of a nonlinear system's behaviour, and enable flight flutter data analysis to be performed, the methodology developed was found to be inadequate for short and noisy data sets. Attention is therefore focused on two methods to alleviate this deficiency, one to reduce the noise that contaminates the time series, and another to concatenate several short experimental data sets. / The properties of the different methodologies are assessed on simulated data, and accurate system parameter identification is obtained. An analysis on real flight test data is then performed with the aim of obtaining modal damping and frequency for the CF-18 aircraft in flight conditions. All the numerical results are discussed, and the effects of noise and the length of data are investigated.

Analysis of the attitude dynamics of a spacecraft is necessary for its successful operation. Recent research has focussed on the object-oriented analysis and design for generating and solving the complex nonlinear dynamic equations of motion of a multibody space system. In this thesis, an effort has been made to develop objects that can be combined to formulate the complete dynamic equations of a spacecraft containing reaction wheels. In order to generate the mathematical model and dynamical equations of the multibody system, a variation of the Lagrange's method has been used, along with the concept of Natural Orthogonal Complement, in order to eliminate the kinematic constraint force and moments. / The designed objects would be part of a multibody system software package that could simulate the complex dynamics of a spacecraft containing reaction wheels and any arbitrary configuration of connected bodies. The objects have been designed such that the spin rate of the wheels may be specified as a constant nominal rate, or as any function of time, or in the form of a P.I.D. control law, wherein the wheel spin rate is a function of the body quaternion of the motherbody. The accuracy, versatility, and adaptability of the designed objects have been illustrated with numerous examples and compared with results obtained using standard procedure. Maneuvers have also been simulated on the designed model and compared with available spacecraft data in order to substantiate the authenticity of the designed objects.

<p> The design of NextGen and current-day cockpit displays are critical for efficient pilot performance and situation awareness on the flight deck. Before deployment of a design into the cockpit the costs and benefits that a display design imposes on performance and situation awareness should be considered. In this thesis, a design tool was developed to support the design of NextGen displays for situation awareness and performance. This design tool is a library of pilot performance estimates. Through literature reviews and meta-analyses of empirical data, the library was developed to provide display designers 1) qualitative distinctions of display properties that either support or limit full situation awareness, and 2) quantitative performance time estimates until situation awareness as a function of various display formats. A systematic method was also developed for future augmentation of the library. </p>