How Things are Designed and How Things Move

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 1/15/2022 UF Flight Controls Lab 2

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 1/15/2022 UF Flight Controls Lab 3

Design in a Nutshell 1/15/2022 UF Flight Controls Lab 4

Design • What are some methodologies? – – – 1/15/2022 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? UF Flight Controls Lab 5

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

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

Why Use CAD? • • Drawing complex parts by hand not easy Ease of modifications Standards Cost Reduction 1/15/2022 UF Flight Controls Lab 8

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

Computer aided manufacturing • 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 Engineering (CAE) • 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

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

Increasing Engine Power • 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

Manual transmission • Transmits the motion from the engine to the wheels

Mechanisms • Def: Some combination of parts and linkages to perform a function • Types of Mechanisms – – – Linear Motion Rotary Motion Intermittent Motion Reciprocating Motion Oscillating Motion Irregular Motion • Examples 1/15/2022 UF Flight Controls Lab 15

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 1/15/2022 UF Flight Controls Lab 16

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! 1/15/2022 UF Flight Controls Lab 17

Flight Dynamics How many degrees of freedom does an aircraft have? 1/15/2022 UF Flight Controls Lab 18

References • • http: //www. victorpest. com/mouse_instructions. htm http: //www. blendernation. com/wp-content/uploads/2007/01/mousetrap_30. jpg http: //www. aiaadbf. org/ http: //en. wikipedia. org/wiki/Mechanism_(technology) http: //images. google. com/imgres? imgurl=http: //upload. wikimedia. org/wikipedia/commons/ thumb/5/5 d/Atlas_V_551_with_New_Horizons_on_Lauch_Pad_41. jpg/396 px. Atlas_V_551_with_New_Horizons_on_Lauch_Pad_41. jpg&imgrefurl=http: //commons. wikim 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=NMIKHOs 41 g_KM: &tbnh=135&tbnw=89&prev=/images%3 Fq%3 Datlas%2 BV%26 um%3 D 1%26 hl%3 D en%26 safe%3 Dactive%26 client%3 Dfirefox-a%26 rls%3 Dorg. mozilla: en-US: official%26 sa%3 DN http: //www. flying-pig. co. uk/mechanisms/index. html http: //ocw. mit. edu/Ocw. Web/Mechanical-Engineering/index. htm http: //www. grc. nasa. gov/WWW/K-12/airplane/rotations. html 1/15/2022 UF Flight Controls Lab 19