DESIGN AND ANALYSIS OF RIGID-BODY SHAPE-CHANGE MECHANISM FOR AIRCRAFT WINGS

2015 ◽  
Vol 77 (21) ◽  
Author(s):  
Mohammad Hazrin Ismail ◽  
Shamsul Anuar Shamsudin ◽  
Mohd Nizam Sudin
Keyword(s):  
Shape Change ◽  
Rigid Bodies ◽  
Main Body ◽  
Programming Technique ◽  
High Lift ◽  
Airframe Noise ◽  
Aircraft Wings ◽  
Prismatic Joints ◽  
A Chain ◽  
Fixed End

Airframe noise reduction becomes a main interest among researchers who study the performance of aircrafts. The airframe noise can occur between the high-lift systems and main body of the airfoil. The proposed shape-changing airfoil is one of many ideas to reduce airframe noise by eliminating the gap between the main body and high-lift systems. This paper presents a new design of 30P30N airfoil, which converts the three-element airfoil (slat, main body and flap) into two-element airfoil (combination of slat and main body as an element and flap) by installing a shape-changing slat into the systems. This work applies a chain of rigid bodies connected by revolute and prismatic joints that are capable of approximating a shape change defined by a set of morphed slat design profiles. To achieve a single degree of freedom (DOF), a building-block approach is employed to mechanize the fixed-end shape-changing chain with the helped of Geometric Constraint Programming technique as an effective method to develop the mechanism. The conventional and shape-change 30P30N airfoils are compared to study the performances of airfoils with the velocity and angle of attack are constant.

scholarly journals Kinematic Synthesis of Planar, Shape-Changing Rigid Body Mechanisms for Design Profiles With Significant Differences in Arc Length

2011 ◽  
Author(s):  
Shamsul A. Shamsudin ◽  
Andrew P. Murray ◽  
David H. Myszka ◽  
James P. Schmiedeler
Keyword(s):  
Rigid Body ◽  
Shape Change ◽  
Rigid Bodies ◽  
Arc Length ◽  
Shape Variation ◽  
Planar Mechanisms ◽  
Revolute Joints ◽  
Prismatic Joints ◽  
Plane Shape ◽  
A Chain

This paper presents a kinematic procedure to synthesize planar mechanisms capable of approximating a shape change defined by a general set of curves. These “morphing curves”, referred to as design profiles, differ from each other by a combination of displacement in the plane, shape variation, and notable differences in arc length. Where previous rigid-body shape-change work focused on mechanisms composed of rigid links and revolute joints to approximate curves of roughly equal arc length, this work introduces prismatic joints into the mechanisms in order to produce the different desired arc lengths. A method is presented to inspect and compare the profiles so that the regions are best suited for prismatic joints can be identified. The result of this methodology is the creation of a chain of rigid bodies connected by revolute and prismatic joints that can approximate a set of design profiles.

Design of Planar, Shape-Changing Rigid-Body Mechanisms for Morphing Aircraft Wings

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Kai Zhao ◽  
James P. Schmiedeler ◽  
Andrew P. Murray
Keyword(s):  
Rigid Body ◽  
Shape Change ◽  
Solution Space ◽  
Closed Curve ◽  
Morphing Aircraft ◽  
Aircraft Wings ◽  
Revolute Joints ◽  
Multi Objective Genetic Algorithm ◽  
Prismatic Joints ◽  
Fixed End

This paper presents a procedure to synthesize planar rigid-body mechanisms, containing both prismatic and revolute joints, capable of approximating a shape change defined by a set of morphing curves in different positions. The existing mechanization process is extended specifically to enable the design of morphing aircraft wings. A portion of the closed-curve morphing chain that has minimal displacement is identified as the structural ground after the segmentation process. Because of the revolute joints placed at the endpoints of the ground section, the moving links of the fixed-end morphing chain need to be repositioned relative to each of the desired wing shapes so as to minimize the error in approximating them. With the introduction of prismatic joints, a building-block approach is employed to mechanize the fixed-end morphing chain. The blocks are located in an assembly position to generate a single degree-of-freedom (DOF) mechanism. Because of the additional constraints associated with prismatic joints compared to revolute joints, the size of the solution space is reduced, so random searches of the design space to find solution mechanisms are ineffective. A multi-objective genetic algorithm is employed instead to find a group of viable designs that tradeoff minimizing matching error with maximizing mechanical advantage. The procedure is demonstrated with a synthesis example of a 1-DOF mechanism approximating eight closed-curve wing profiles.

Singularity Traces of Planar Linkages That Include Prismatic and Revolute Joints

2015 ◽  
Author(s):  
Saleh M. Almestiri ◽  
David H. Myszka ◽  
Andrew P. Murray ◽  
Charles W. Wampler
Keyword(s):  
Shape Change ◽  
Rigid Bodies ◽  
Closed Curves ◽  
Revolute Joints ◽  
Prismatic Joints ◽  
Kinematic Position ◽  
Motion Characteristics ◽  
Forward Kinematic ◽  
Planar Linkages ◽  
General Method

This paper presents a general method to construct a singularity trace for single degree-of-freedom, closed-loop linkages that include prismatic, in addition to, revolute joints. The singularity trace has been introduced in the literature as a plot that reveals the gross motion characteristics of a linkage relative to a designated input joint and design parameter. Previously, singularity traces were restricted to mechanisms composed of only rigid bodies and revolute joints. The motion characteristics identified on the plot include changes in the number of solutions to the forward kinematic position analysis (geometric inversions), singularities, and changes in the number of branches. To illustrate the adaptation of the general method to include prismatic joints, basic slider-crank and inverted slider-crank linkages are explored. Singularity traces are then constructed for more complex Assur IV/3 linkages containing multiple prismatic joints. These Assur linkages are of interest as they form an architecture that is commonly used for mechanisms capable of approximating a shape change defined by a general set of closed curves.

scholarly journals Aeroelastic Stability Analysis of Electric Aircraft Wings with Distributed Electric Propulsors

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 100
Author(s):  
Mohammadreza Amoozgar ◽  
Michael I. Friswell ◽  
Seyed Ahmad Fazelzadeh ◽  
Hamed Haddad Khodaparast ◽  
Abbas Mazidi ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Electric Propulsion ◽  
Aeroelastic Stability ◽  
Concentrated Mass ◽  
High Lift ◽  
Aircraft Wings ◽  
Time Space ◽  
Beam Equations ◽  
Geometrically Exact Beam ◽  
Electric Aircraft

In this paper, the effect of distributed electric propulsion on the aeroelastic stability of an electric aircraft wing was investigated. All the electric propulsors, which are of different properties, are attached to the wing of the aircraft in different positions. The wing structural dynamics was modelled by using geometrically exact beam equations, while the aerodynamic loads were simulated by using an unsteady aerodynamic theory. The electric propulsors were modelled by using a concentrated mass attached to the wing, and the motor’s thrust and angular momentum were taken into account. The thrust of each propulsor was modelled as a follower force acting exactly at the centre of gravity of the propulsor. The nonlinear aeroelastic governing equations were discretised using a time–space scheme, and the obtained results were verified against available results and very good agreement was observed. Two case studies were considered throughout the paper, resembling two flight conditions of the electric aircraft. The numerical results show that the tip propulsor thrust, mass, and angular momentum had the most impact on the aeroelastic stability of the wing. In addition, it was observed that the high-lift motors had a minimal effect on the aeroelastic stability of the wing.

On the Usage of Dynamic Vibration Absorbers for Reduction of Forced Vibrations of a System of Coupled Rigid Bodies

2009 ◽  
Author(s):  
Dmitry Chebanov ◽  
Alexander M. Kovalev ◽  
Irina A. Bolgrabskaya ◽  
Vladimir F. Shcherbak
Keyword(s):  
Forced Vibrations ◽  
Rigid Bodies ◽  
Vibration Absorbers ◽  
Constant Mass ◽  
External Perturbations ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers ◽  
Controlled Motion ◽  
A Chain ◽  
Chain Links

In this paper we study the problem of neutralizing the forced vibrations of a chain of heavy rigid bodies coupled by one-degree-of-freedom joints using dynamic vibration absorbers. Each absorber is modeled by a system that has a constant mass and is capable of making instantaneous changes in its stiffness. We propose and analyze several strategies for introducing the absorbers that differ from each other by the number of absorbers attached and the way they are positioned on the chain links. In particular, we suggest a way to choose the parameters of the absorbers so that their controlled motion totally compensates the effect of the external perturbations.

scholarly journals Epidemiology of Chain Saw Related Injuries, United States: 2009 through 2013

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Bart Hammig ◽  
Ches Jones
Keyword(s):  
Emergency Department ◽  
Surveillance System ◽  
Prevention And Control ◽  
Main Body ◽  
Severe Injuries ◽  
Injury Surveillance System ◽  
Ed Visits ◽  
Using Data ◽  
A Chain ◽  
And Control

Problem. Chain saws are a commonly used tool with the potential to inflict severe injuries. Methods. Descriptive epidemiological estimates for emergency department (ED) visits for injuries associated with the use of a chain saw were calculated using data from the National Electronic Injury Surveillance System for the years 2009–2013. Results. A total of 115,895 ED visits for injuries related to the use of a chain saw occurred during the study period. Most injury visits occurred among males (95%) and persons aged 30–59 years and during the months of September through November. The main body sites injured were the hand/fingers and knee. The majority of injuries were lacerations (80%). Conclusions. Chain saw injuries present with characteristic patterns which can aid in prevention of injuries related to the use of these tools. Examination of the epidemiology of chain saw injuries will help to ascertain targeted needs for prevention and control efforts.

Noise Reduction in a High Lift Wing Using SMAs: Computational Fluid-Structural Analysis

2016 ◽  
Author(s):  
William Scholten ◽  
Ryan Patterson ◽  
Darren Hartl ◽  
Thomas Strganac ◽  
Jeff Volpi ◽  
...  
Keyword(s):  
Structural Model ◽  
Leading Edge ◽  
Fluid Models ◽  
Cfd Analysis ◽  
High Lift ◽  
Airframe Noise ◽  
Weakly Coupled ◽  
Tunnel Model ◽  
Slat Noise ◽  
Flow Speeds

The leading-edge-slat on an aircraft is a significant contributor to the airframe noise during the low speed maneuvers of approach and landing. It has been shown in previous work that the slat noise may be reduced with a slat-cove filler (SCF). The objective of this current work is to determine how the SMA SCF behaves under steady flow using finite element structural models and finite volume (FV) fluid models based on a scaled wind tunnel model of a newly considered multi-element wing with a SCF. Computational fluid dynamics (CFD) analysis of the wing is conducted at multiple angles of attack, different flow speeds and high lift device deployment states. The FV fluid models make use of overset meshes, which overlap a slave mesh (that can undergo movement and deformation) unto a fixed master mesh, allowing for retraction and deployment of the slat and flap in the CFD analysis. The structural and fluid models are linked using a previously developed framework that permits the use of custom user material subroutines (for superelastic response of the SMA material) in the structural model, allowing for the performance of fluid-structure interaction (FSI) analysis. The fluid and structural solvers are weakly coupled such that the fluid solver transfers pressure data and the structural solver transfers displacements, but the physical quantities of each program are solved independently. FSI results are shown for the cases of the slat/SCF in the fully-deployed configuration as well as for the case of the slat/SCF undergoing retraction in flow.

Investigation of Airframe Noise from High Lift Configuration Model

2008 ◽  
Author(s):  
Hiroki Ura ◽  
Yuzuru Yokokawa ◽  
Taro Imamura ◽  
Takeshi Ito ◽  
Kazuomi Yamamoto
Keyword(s):  
Configuration Model ◽  
High Lift ◽  
Airframe Noise
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