How Things are Designed and How Things Move Robert Love, Venkat Jayaraman June 26, 2008 SSTP Seminar – Lecture 3

Overview Organizational Details Presentation – Design, CAD, Automobiles, Mechanisms, Dynamics Discussion Activity – Brief CAD sketch – Aircraft Dynamics 9/9/2015UF Flight Controls Lab2

Design Carnegie Mellon definition: – "Design is the process of taking something from its existing state and moving it to a preferred state" 1.Problem or need is identified, often by a customer with specifications 2.Solution is designed – Conceptual Design (brainstorming, trade studies) – Preliminary Design (testing, initial modeling, performance, cost) – Detailed Design (more testing, end is final product) 3.Realization of design (production) 4.Implementation to meet need 5.Generally sequential, iterative 9/9/2015UF Flight Controls Lab3

Design in a Nutshell 9/9/2015UF Flight Controls Lab4

Design What are some methodologies? – Bio-Inspired, ergonomic, aesthetic, usability – KISS principle-No Rube Goldberg Machines! – User centered vs. Use-centered – Form vs. Function – Best way to catch a mouse? 9/9/2015UF Flight Controls Lab5

Engineering drawing CAD software Computer aided machining Computer aided engineering How automobiles move – Engine System – Manual transmission system Overview

Convey the following information – Geometry – Dimensions – Tolerances – Material – Finish Engineering drawing

Why Use CAD? 9/9/2015UF Flight Controls Lab8 Drawing complex parts by hand not easy Ease of modifications Standards Cost Reduction

Drafting – Autocad, Alibre, Solidedge layout Solid Modelling – Pro E, Solidworks, Ideas, Solidedge, Unigraphics Analysis – Ansys, CATIA,Nisa, Nastran CAD softwares

CAM – Programming tool that helps manufacture physical model using CAD softwares. Implemented by CNC machines CAD drawing -> G-Code -> Computer controlled manufacturing processes such as turning and drilling Computer aided manufacturing

Use of information technology in tasks such as analysis, simulation and design CAE areas covers – Stress analysis on components - FEA (Finite element analysis) – Thermal and fluid flow analysis -CFD (Computational fluid dynamics) – Mechanical event simulation – Optimization Phases of CAE – Pre-processing – defining the model and environmental factors to be applied to it – Analysis solver – High performance computers – Post processing – Visualization of results Computer Aided Engineering (CAE)

Engine system – Converts gasoline into motion Four major strokes – Intake, Compression, Power and exhaust Engine system Main parts of engine are Piston Crankshaft Connecting rod Valves Ports Sump Spark plug

Increasing stroke displacement Increasing compression ratio Cramming more air fuel mixture into each cylinder Cooling the incoming air Allowing intake and exhaust mixture to flow more easily Lighter parts Increasing Engine Power

Transmits the motion from the engine to the wheels Manual transmission

Mechanisms Def: Some combination of parts and linkages to perform a function Types of Mechanisms – Linear Motion Linear Motion – Rotary Motion – Intermittent Motion – Reciprocating Motion – Oscillating Motion – Irregular Motion Examples 9/9/2015UF Flight Controls Lab15

Analyzing Things Statics – Description of behaviors without movement Dynamics – Kinematics: study of motion without respect to the forces applied – Kinetics: study of motion under the influence of forces 9/9/2015UF Flight Controls Lab16

Simplified Models Important Concepts: – Inertial Reference Frame vs. Body Fixed Reference Frame – Right vs. Left Handed Coordinate System – Scalars, Vectors and Matrices, Coordinate Transformations, Transport Theorem – Identify Degrees of Freedom – Dealing with Forces: Newton’s Laws – Tip: Look for symmetry! – Tip: Note assumptions! 9/9/2015UF Flight Controls Lab17

Flight Dynamics 9/9/2015UF Flight Controls Lab18 How many degrees of freedom does an aircraft have?

References thumb/5/5d/Atlas_V_551_with_New_Horizons_on_Lauch_Pad_41.jpg/396px- Atlas_V_551_with_New_Horizons_on_Lauch_Pad_41.jpg&imgrefurl= edia.org/wiki/Image:Atlas_V_551_with_New_Horizons_on_Lauch_Pad_41.jpg&h=599&w=39 6&sz=65&hl=en&start=2&um=1&tbnid=NMIKH- Os41g_KM:&tbnh=135&tbnw=89&prev=/images%3Fq%3Datlas%2BV%26um%3D1%26hl%3D en%26safe%3Dactive%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN /9/2015UF Flight Controls Lab19