3,350 research outputs found

    Numerical Algorithm for Wing-Structure Design

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    Low-fidelity aerostructural optimization routines have often focused on determining the optimal spanloads for a given wing configuration. Several analytical approaches have been developed that can predict optimal lift distributions on rectangular wings with a specific payload distribution. However, when applied to wings of arbitrary geometry and payload distribution, these approaches fail. Increasing the utility and accuracy of these analytical methods can result in important benefits during later design phases. In this paper, an iterative algorithm is developed that uses numerical integration to predict the distribution of structural weight required to support the bending moments on a wing with arbitrary geometry and payload distribution. It is shown that the algorithm’s predictions for the structural weight of a rectangular test wing match those found using an analytical approach. The structural weight distribution for a spanwise-constant non-structural weight distribution is also found. Coupling the algorithm with an optimization routine, the optimal lift distributions for the rectangular test wing are found and are shown to match analytical results. Finally, the optimal lift distributions for a test wing configuration with a spanwise-constant non-structural weight distribution are found using the algorithm

    Migrating Legacy Systems in the Global Merger & Acquisition Environment

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    The MetaFrame system migration project at WorldPharma, while driven by merger and acquisition, had faced complexities caused by both technical challenges and organizational issues in the climate of uncertainties. However, WorldPharma still insisted on instigating this post-merger system migration project. This project served to (1) consolidate the separated legacy MetaFrame systems from the three pre-merger pharmaceutical organizations into one globally managed system and (2) develop a global support team for the newly consolidated global MetaFrame system. This system migration project was aligned with WorldPharma’s IT strategy that aimed to streamline its IT resources and enhance system efficiency

    Migrating Legacy Systems in the Global Merger & Acquisition Environment Teaching Case

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    MetaFrame system migration project at Worldpharm, driven by the fiesta of merger and acquisition, had engendered both technical challenges and convoluted organizational issues in the climate of uncertainties. This project was aligned with IT strategy that aimed to streamlining IT resources and enhancing system efficiency of the post-merger organization. In spite of recognizing that it was treading in the treacherous water, Worldpharm still insisted on instigating this post-merger MetaFrame system migration project, which served to (1) consolidate all legacy MetaFrame systems from the three pre-merger pharmaceutical organizations into one globally managed system and (2) develop a global support team for the globally managed MetaFrame system

    Effect of Business Characteristics and ERP Implementation Strategies on ERP Outcomes: An Exploratory Study

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    Although much academic research has been done on various ERP-related issues, little research has focused on the effects of business characteristics and ERP implementation strategies on the outcomes resulted from implementing ERP. Thus, the focus of this study is to explore the effects of business characteristics and ERP implementation approaches on ERP outcomes. To this end, data collected from 256 Korean manufacturing firms were analyzed by Cluster Analysis to identify groups of companies having similar business characteristics and adopting similar ERP implementation approaches. Then, the differences in ERP outcomes among these groups of companies were examined. Results showed that large manufacturing firms with make-to-order production approach had significantly higher perceived benefits in external coordination than other firms

    Attainable Moment Set and Actuation Time of a Bio-Inspired Rotating Empennage

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    Future tactical aircraft will likely demonstrate improvements in efficiency, weight, and control by implementing bio-inspired control systems. This work analyzes a novel control system for a fighter aircraft inspired by the function of – and the degrees of freedom available in – a bird’s tail. The control system is introduced to an existing fighter aircraft design by removing the vertical tail and allowing the horizontal tail surfaces to rotate about the roll axis. Using a low-fidelity aerodynamic model, an analysis on the available controlling moments and actuation speeds of the baseline aircraft is compared to that of the bio-inspired rotating empennage design. The results of this analysis at a takeoff and approach flight condition indicate that the bio-inspired tail design is able to improve upon the baseline in terms of control power available for yaw by up to 170%, while also improving the actuation speed by about 450 milliseconds for moments about the pitch axis. The bio-inspired design is shown to have actuation times that are up to 600 milliseconds slower for generating yawing moments and a reduced roll control contribution from the tail in certain moment combinations. The impacts of these issues on control will need to be determined with analysis at additional flight conditions and a flight dynamics analysis

    Evaluation of First-Order Actuator Dynamics and Linear Controller for a Bio-Inspired Rotating Empennage Fighter Aircraft

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    This paper considers the problem of stabilizing a bio-inspired fighter aircraft variant at its Air Combat Maneuver Condition. The aircraft equations of motion are linearized, and an infinite-horizon linear quadratic regulator design is conducted for this aircraft. Included in the dynamics are first-order actuator models, which have the effect of slowing actuator responses. This is particularly important for the bio-inspired variant because it requires rotation of the empennage, which has relatively large inertia. The bio-inspired variant open-loop system is unstable in the short period and Dutch roll modes, which is mitigated in the closed-loop system. Monte Carlo simulation responses to initial condition dispersions, aerodynamic model errors, and atmospheric turbulence are presented for the controlled aircraft system. These simulations demonstrate the robust properties of the presented control design. Discussion is dedicated to control designs neglecting input from throttle and the rotating tail, and corresponding successes. Whereas the bio-inspired variant aircraft can be successfully controlled without rotating tail input, effects from neglecting throttle input show throttle should be included, but perhaps in an alternate loop such as a speed controller

    Mechanization of a High Aspect Ratio Wing for Aerodynamic Control

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    Investigations are conducted to mechanize a controlled spanwise-varying airfoil camber change for a high aspect ratio wing, resulting in optimized aerodynamic performance for a aircraft that changes weight by 50% over its mission. Mechanisms to achieve these shape changes are designed based on two separate design methodologies: a rigid body kinematics approach and a compliant mechanism approach. A framework for optimizing mechanisms based on each approach is presented. Differences between the approaches are illustrated through the design of a mechanism for a specific set of airfoil shapes. Mechanisms are evaluated based on the error in the shapes and on the energy efficiency of the systems

    A Review of Avian-Inspired Morphing for UAV Flight Control

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    The impressive maneuverability demonstrated by birds has so far eluded comparably sized uncrewed aerial vehicles (UAVs). Modern studies have shown that birds’ ability to change the shape of their wings and tail in flight, known as morphing, allows birds to actively control their longitudinal and lateral flight characteristics. These advances in our understanding of avian flight paired with advances in UAV manufacturing capabilities and applications has, in part, led to a growing field of researchers studying and developing avian-inspired morphing aircraft. Because avian-inspired morphing bridges at least two distinct fields (biology and engineering), it becomes challenging to compare and contrast the current state of knowledge. Here, we have compiled and reviewed the literature on flight control and stability of avian-inspired morphing UAVs and birds to incorporate both an engineering and a biological perspective. We focused our survey on the longitudinal and lateral control provided by wing morphing (sweep, dihedral, twist, and camber) and tail morphing (incidence, spread, and rotation). In this work, we discussed each degree of freedom individually while highlighting some potential implications of coupled morphing designs. Our survey revealed that wing morphing can be used to tailor lift distributions through morphing mechanisms such as sweep, twist, and camber, and produce lateral control through asymmetric morphing mechanisms. Tail morphing contributes to pitching moment generation through tail spread and incidence, with tail rotation allowing for lateral moment control. The coupled effects of wing–tail morphing represent an emerging area of study that shows promise in maximizing the control of its morphing components. By contrasting the existing studies, we identified multiple novel avian flight control methodologies that engineering studies could validate and incorporate to enhance maneuverability. In addition, we discussed specific situations where avian-inspired UAVs can provide new insights to researchers studying bird flight. Collectively, our results serve a dual purpose: to provide testable hypotheses of flight control mechanisms that birds may use in flight as well as to support the design of highly maneuverable and multi-functional UAV designs

    Kinematically Designed Flexible Skins for Morphing Aircraft

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    ABSTRACT This investigation targeted the development of flexible materials that when combined with mechanized structures can enable large rigid body deformations of aircraft structures while maintaining its aerodynamic shape. The solution presented in this work focuses on determining the distribution of material properties to design such a skin using topology optimization techniques. The matrix material selected in this research is a representative Shape Memory Polymer (SMP), which is embedded with a reinforcing fiber. The fiber plays a dual role in that in addition to serving as a reinforcing element it also provides the means to activate the material response (e.g., changing cross link density) via resistive heating. In depth heat transfer analysis and experiments were conducted to understand power requirements and minimum spacing of the fibers to activate the desired material response
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