Landing Gear Design Analysis. David Sandells Lecturer in Aerospace Engineering

Transcription

1 Landing Gear Design Analysis David Sandells Lecturer in Aerospace Engineering

2 Mission Statement 2-25 We aspire to be a dynamic, global, enterprising university. We will work in partnership with external organisations through our research and engage our students as partners in a community of learning.

3 David Sandells (MEng, CEng (MIET) Lecturer in aircraft system design (undergraduate & postgraduate). Landing gear, hydraulics, electrical systems, structural design and industrial project management & sustainable aviation. Industry experience (Chief, Principal & Systems Engineer). 787 Landing Gear valves and uplocks Merlin Electrical primary flight actuation system Fuel systems, hydro-mechanical & electro-mechanical actuation systems Patents in electrical thrust reverser design and actuator design. Aviation enthusiast BGA gliding instructor, NPPL (SLMG), MGIR

4 University Profile The Guardian League Table

5 Key Facts Origins rooted in industry - Founded 843, well-known and highly respected as Lanchester Poly from 97s, became Coventry University 992 as one of the modern universities Modern City Centre campus on single 33-acre site London campus opened 2 International Offices in China, Nigeria, Pakistan and Kenya Over 7, students (5% International) Approximately 2,5 staff New 55m Engineering & Computing building opened September 22 World-leading and internationally excellent research in every Faculty - 7 out of 6 areas receiving the highest rating in overall quality profile in the RAE 28 A Top 25 UK Higher Education Institution (Working with business and supporting the economy)..4m HEIF5 Investment Entrepreneurial University of the Year (Times Higher Education Awards, November 2) Coventry University risen to 46 th overall (Sunday Times University Guide 24, September 23)

6 Key Facts Modern City Centre campus on single 33-acre site Over 7, students (5% International) Approx. 2,5 staff World-leading and internationally excellent research in every Faculty - 7 out of 6 areas receiving the highest rating in overall quality profile in the RAE 28 A Top 25 UK Higher Education Institution (Working with business and supporting the economy)..4m HEIF5 Investment 2-25.

7 World Class Facilities 55m Engineering and Computing building (22) 32m Students Hub (2) 2-acre 2m Technology Park (23) Innovation Centre (for new enterprises), Design Cluster, Enterprise Centre and state-of-the-art conference facilities Bugatti Building (housing digital/modeling labs) opened (22), sports complex (24) 6m Library (2)

8 The Faculty of Engineering & Computing The students we educate and the companies we serve demand the same: responsive expertise delivered when it is required and followed up by advice and value for money support. 3 Academic Staff 35 Undergraduate Students 8 Postgraduate Students (MSc/MBA) 5 Research Students (PhD/MPhil/MSc) Activity Led Learning (ALL) Applied research - relevant to today s challenges Providing real business impact Mitigating risk through technical solutions Delivering value for money Empowerment through expert advice Creating and maintaining effective and rewarding relationships

9 Our Aerospace Teaching Undergraduate Aerospace Systems Engineering Royal Aeronautical Society (CEng) Overall Satisfaction 97% Aerospace Technology Royal Aeronautical Society ( Exemplar IEng) Overall Satisfaction 89% Postgraduate Aerospace Engineering Aerospace Manufacturing Engineering

10 Key Research Activities COGENT Research centre World-leading applied research centre Dedicated to analysis and development of sensing-based sociotechnical systems. Dual focus: robust, deployable pervasive sensing systems for real-life applications at scale; and effective packages for empowering users to maximise the benefits of those systems. HEAT - Highly Efficient Autonomous Thermocouple system Wireless temperature sensing and health monitoring Partnered with Vibro-Meter UK

11 Capabilities Disciplines Structural Engineering Software Engineering Rehabilitation Engineering Motorsport Engineering Mechanical Engineering Mathematics Materials Engineering Electronics Engineering Electrical Engineering Digital Security & Forensics Computer Networking Computer Hardware & Software Engineering Communications Engineering Control Engineering Civil Engineering & Architecture Automotive Engineering Aerospace Engineering Application Sectors Transport & Logistics Manufacturing Health Finance Environment Energy Digital Security Digital Media Defence ICT Built Environment Automotive Aerospace Technologies Vehicle Structural Optimisation Stress Analysis Rapid Prototyping Mobile Applications Low Carbon Vehicle Technologies Games Technology Digital Forensics Control Systems Computer Visualisation Composite Materials Multidisciplinary Capabilities Product Design & Engineering Metrology Lean Manufacturing Design & Ergonomics Sustainability Supply Chain Management Simulation & Modelling Marketing Knowledge Management Business Management

12 Today s talk Explaination of typical landing gear calculations. Demonstration using SMath software tool Preliminary aircraft design stage Focus on Kinematic Analysis Landing loads

13 SMath Software Maths software problems: Cannot read equations easily Unit conversions Results rather than method displayed Hard to add comments Printing in a reviewable format SMath Freely available Paper interface Handles Units No affiliation with Coventry University Use at own risk

14 KINEMATICS

15 Kinematics Analysis of Mechanism Movement

16 Finding Mechanism Position φ d l Vary φ until d = l We need a function: d(φ) Find φ where: d φ l =

17 Finding positions of joints Y How do we find the position of J2 relative to the origin. Given that the mechanism rotates. Whilst avoiding trigonometry! J2

18 Vector Representation of Positions X Y 3 2 Frame X Y Frame 2 = T 6 4 Translation Rotations 2 3 = = Pt F Coordinates of point relative to Frame

19 Vector Representation of Positions X Y Frame T 2 ( ) ( ) ( ) ( ) = 4 cos sin 6 sin cos 2 T ( ) ( ) ( ) ( ) = cos sin 6 sin cos y x Rotation about Z

20 Vector Representation of Positions X Y Frame T 2 ( ) ( ) ( ) ( ) = 2 3 cos sin sin cos 4 6 y x Order is important Translate Rotate Pt

21 Vector Representation of Positions X Y Z Can translate in x, y and z directions Can rotate around x, y and z axis We can use a 4x4 matrix to define these transforms 2 3

22 Transformation Matrices Homogeneous Matrices representation ( ) =,, z y x z y x Trl ( ) ( ) ( ) ( ) ( ) = cos sin sin cos R X ( ) ( ) ( ) ( ) ( ) = cos sin sin cos R Y ( ) ( ) ( ) ( ) ( ) = cos sin sin cos R Z

23 Transform inversions We can go the other way by inverting the matrix (M - ) :- T 2 = cos sin ( ) sin( ) ( ) cos( ) 6 4 Goes from frame to frame 2 T 2 = cos sin ( ) sin( ) ( ) cos( ) 6 4 Inverted - Goes from frame 2 to frame

24 F F F4 F3 F2

25 F F F4 F3 F2 T 2 = TTT(ll x, ll y, ) T 23 (φ) = R Z (φ) T 34 = TTT( ll,,) T () = R Z () Position of F4 relative to F7 T 7 = TTT(, ll,) x74 y 74 = T2 T23( ϕ) T34 z 74 T7 T( ) F 7 F 4 = f (, ϕ )

26 Walkthrough KINEMATIC CALCULATIONS IN SMATH SEE EXAMPLE FILE

27 LANDING LOADS

28 m : Mass of aircraft V : Vertical Decent Velocity KE = 2 m v 2

29 ( ) PE = m g S S + S T S s : Shock Compression S T : Tyre Compression

30 Shock Absorber Modelling Given component characteristics we can predict landing gear response. Most gear have a static and dynamic response Spring F(pppp) Damper F(vvv)

31 Shock Absorber Modelling Air Springs polytrophic process PP n = C Puuu ggg: n =.35 MMMMM: n =. (typical) Dampers Fluid flow through an orifice P = 2 cc2 ρ v2 Leaf spring Cantilever bending d2 v = BB(x) dx 2 E I(x) v = BB(x) E I(x) dd σ = BB(x) I x Springs, Bungees, Tyres Linear approximation or Lookup table t 2

32 LANDING LOAD SIMULATIONS

33 Modelling the response An approximation fixed time step model:- Start at the point of touchdown Position = Vertical Speed = Vertical Sink Speed Deceleration = F M Calculate force from position & vertical speed Calculate deceleration from the force Move forward a time-step Calculate new vertical speed (deceleration over time-step) Calculate position (velocity over time-step)

34 Walkthrough LANDING LOAD SIMULATIONS IN SMATH SEE EXAMPLE FILE

35 Coventry University Courses Next Courses 7-7 th April 24 Look out for booking on LAA website (under training) Design Courses: Design for Manufacture Aerodynamics theory and practice (wind-tunnel) Aerodynamic Simulation (CFD) Flight Simulation and Performance (Simulators) Landing Gear & System Design Focus on free/open source or inexpensive software Stress Courses: Fundamental Stress Analysis Introduction to the Finite Element Method Composite Material Stress Analysis