Introduction To Design

16.810Engineering Design and Rapid PrototypingLecture 1Introduction to DesignInstructor(s)Prof. Olivier de WeckTeachingAssistants:January 9, 2007Anas AlfarisNii Armar

Happy New Year 2007 !We won’t be designing White Knight or SpaceShipOne this IAP, but .You will learn about “the design process” and fundamentalbuilding blocks of any complex (aerospace) system16.8102

Quote “The scientist seeks to understandwhat is; the engineer seeks tocreate what never was” 16.810-Von Karman3

Outline Organization of 16.810 (Re-) Introduction to Design 16.810Examples, Requirements, Design Processes(Waterfall vs. Spiral), Basic Steps“Design Challenge” - Team Assignments Motivation, Learning Objectives, ActivitiesPrevious Years (2004, 2005)This Year: MITSET (30 min), VDS (30 min)Deliverables Checklist, Team AssignmentsFacilities Tour4

Organization of 16.81016.8105

Expectations 6 unit course (3-3-0) – 7 1 sessions 16.810TR1-5 in 33-218 , must attend all sessions orget permission of instructors to be absentThis is for-credit, no formal “problem sets”,but expect a set of deliverables (see -list)Have fun, but also take it seriouslyThe course is a 3rd year “prototype” itself andwe are hoping for your feedback &contributionsOfficially register under 16.810 (Jan 2007) onWEBSIS6

History of this CourseDecember 2002Undergraduate Survey in Aero/Astro Department.Students expressed wish for CAD/CAE/CAM experience.April 4, 2003Submission of proposal to Teaching and EducationEnhancement Program (“MIT Class Funds")May 6, 2003Award Letter received from Dean for UndergraduateEducation ( 17.5k)June 5, 2003Kickoff MeetingSept 18, 2003Approved by the AA undergraduate committee (6 units)Fall 2003Jan 5, 2004PreparationFirst Class (Topic: Bicycle Frame Design)Fall 2004PreparationJan 4, 2005Second Class (Topic: Race Car Wing Design)Jan 2007Third Class Æ Focus on helping student projectssee: http://ocw.mit.edu16.8107

Needs – from studentsA 2001 survey of undergraduate students(Aero/Astro) – in conjunction with new Dept. headsearch- There is a perceived lack of understanding and training inmodern design methods using state-of-the-art CAD/CAE/CAMtechnology and design optimization.- Individual students have suggested the addition of a short andintense course of rapid prototyping, combined with designoptimization.16.8108

Boeing List of “Desired Attributes of an Engineer” A good understanding ofengineering sciencefundamentals Mathematics (including statistics)Physical and life sciencesInformation technology (far more than“computer literacy”) A multi-disciplinary, systemsperspectiveA basic understanding of thecontext in which engineering ispracticed 16.810Economics (including businesspractice)HistoryThe environmentCustomer and societal needsGood communication skills A good understanding of designand manufacturing processes (i.e.understands engineering) WrittenOralGraphicListeningHigh ethical standardsAn ability to think both criticallyand creatively - independentlyand cooperativelyFlexibility. The ability and selfconfidence to adapt to rapid ormajor changeCuriosity and a desire to learn forlifeA profound understanding of theimportance of teamwork. This is a list, begun in 1994, of basic durable attributesinto which can be mapped specific skills reflecting thediversity of the overall engineering environment in whichwe in professional practice operate. This current version of the list can be viewed on the Boeingweb site as a basic message to those seeking advice fromthe company on the topic. Its contents are also includedfor the most part in ABET EC 2000.9

An engineer should be able to . Determine quickly how things work Determine what customers want Create a concept Use abstractions/math models to improve a concept Build or create a prototype version Quantitatively and robustly test a prototype to improveconcept and to predict Determine whether customer value and enterprisevalue are aligned (business sense) Communicate all of the above to various audiences Much of this requires “domain-specific knowledge” and experience Several require systems thinking and statistical thinking All require teamwork, leadership, and societal awarenessSlide from Prof. Chris Magee16.81010

Leads toCourse ObjectiveDevelop a holistic view and initialcompetency in engineering design byapplying a combination of human creativityand modern computational tools to thesynthesis of a simple component or system.16.81011

Mind Map“Holistic View” - of thewhole. Think about:- requirements,design, manufacturing,testing, cost .“Engineering Design”- what you will likelydo after MIT“Competency” - can notonly talk about it ordo calculations, butactually carry out theprocess end-to-end16.810“Human Creativity andComputational Tools”:design is a constant interplay of synthesis and analysis16.810“Rapid Prototyping” a hot concept inindustry today.“Components / Systems”:part of all aerospace systems,But must be “easy” toimplement in a short time12

Course Concept16.81013

Course Flow Diagram (2007)Learning/ReviewProblem statementDeliverablesDesign Intro / SketchHand sketching(A) Requirementsand InterfaceDocumentCAD IntroductionInitial CAD design(B) Hand SketchFEM/Solid MechanicsFEM analysisAvionics PrototypingOptimizationCAM ManufacturingRevise CAD design(C) Solidworks CADModel, PerformanceAnalysisParts FabricationFabrication,Assembly, Testing Guest Lectures16.810Test(D) Manufacturingand Test Reportwith Cost EstimateFinal Review(E) CDR PackageAssembly14

Learning ObjectivesAt the end of this class you should be able to (1) Carry out a systematic design process from conception throughdesign/implementation/verification of a simple component or system.(2) Quantify the predictive accuracy of CAE versus actual test results.(3) Explain the relative improvement that computer optimization canyield relative to an initial, manual solution.(4) Discuss the complementary capabilities and limitations of thehuman mind and the digital computer (synthesis versus analysis).16.81015

Grading Letter Grading A-FComposition Design Deliverables* 16.81020%Requirements Compliance“Quality”Active Class Participation 70%Requirements Document, Sketch, CAD Model &Analysis, Test & Mfg Report, Final Review SlidesFinal Product *see checklist10%Attendance, Ask Questions, Contribute Suggestions,Fill in Surveys16

(Re-)Introduction toDesign16.81017

Product Development - DesignImproved time-to-climbPerformance of F/A-18 inAir-to-Air configuration by 20%Developmentof Swiss F/A-18 Low DragPylon (LDP) 1994-1996“design” –to create, fashion, execute,or construct according to planMerriam-Webster16.81018

Design and Objective SpaceDesign SpaceDesign VariablesWing Area31.5 [in2]Objective SpaceRemember Unified ?Balsa GliderAspect RatioPerformanceTime-of-Flight5.35 secDistance6.2Ca. 90ftDihedral Angle0 [deg]CostAssembly TimeFixed Parameters- air density- properties of balsa wood16.81087 minMaterial Cost 4.5019

Basic Design Steps“flying wing”“monoplane”“biplane”“delta dart”1. Define Requirements2. Create/Choose Concept3. Perform Design4. Analyze System5. Build Prototype6. Test Prototype7. Accept Final Design16.81020

Typical Design PhasesRequirementsDefinitionConceptualDesign General arrangement and performanceRepresentative configurationsGeneral internal baseline Sophisticated Analysis Problem Decomposition Multidisciplinary optimizationDetailedDesign Systems specificationsDetailed subsystemsInternal arrangementsProcess designProductionbaselineProductionand support16.81021

Phased vs. Spiral PD ProcessesPhased, Staged, or Waterfall PD Process(dominant for over 30 esignDetailDesignIntegrateand TestProductLaunchSpiral PD Process(primarily used in software development)Define, Design, Build, Test, IntegrateProductPlanningDefine, Design, Build, Test, IntegrateProductLaunchDefine, Design, Build, Test, IntegrateProcess Design Questions: How many spirals should be planned? Which phases should be in each spiral? When to conduct gate reviews?16.81022

Stage Gate PD ntegration efs: Robert Cooper, Winning at NewProducts 3rd ed., 2001.23

Spiral PD ProcessDetailedDesignIntegration& TestReviewsSystem-LevelDesignCost(Cumulative Effort)ReleasePlanningConceptDesign16.810Rapid PrototypingIs typically associatedWith this process24

Basic Trade-offs in Product DevelopmentPerformanceScheduleRiskCost Performance - ability to do primary mission Cost - development, operation life cycle cost Schedule - time to first unit, production rate Risk - of technical and or financial failureRef: Maier, Rechtin, “The Art of Systems Architecting”16.81025

Key Differences in PDP’s 16.810Number of phases (often a superficial difference)Phase exit criteria (and degree of formality)Requirement “enforcement”ReviewsPrototypingTesting and ValidationTiming for committing capitalDegree of “customer” selling and interferenceDegree of explicit/implicit iteration (waterfall or not)Timing of supplier involvement26

Hierarchy I: Parts Level deck components Ribbed-bulkheadsApproximate dimensions 430mm x 150mm x 25.4mmWall thickness 2mmkeelkeel Ribbed-bulkheadApproximate dimensions 16.810framesRibbed-bulkheadsApproximate dimensions 250mm x 350mm x 30mmWall thickness 2.54mmframe components decks430mm x 660mm x 25.4mmWall thickness 2.54mm27

Hierarchy II: Assembly LevelLoft Boeing (sample) parts A/C structural assembly Nacelle2 decks3 framesKeelFWD DecksLoft included to showinterface/stayout zone toA/CAll Boeing parts in Catiafile format KeelFiles imported intoSolidWorks byconverting to IGESformat(Loft not shown)FramesAft Decks16.81028

Product ComplexityAssume 7-tree log(# parts ) # levels log(7) How many levels in drawing tree? #parts 16.810ScrewdriverRoller BladesInkjet PrinterCopy M)(Boeing)3303002,00010,000100,000#levels1 simple23456complex29

“Design Challenge” andTeam Assignments16.81030

Project Description – IAP 2004ConfigurationLaser displacementsensorsMeasured δ 1displacementsF1Applied dFixedModel Bicycle Frame on 2-D plateMaterial: Al 6061-T6Thickness ¼”Scale ca. 1:516.81031

Project Deliverables – IAP 200416.81032

Project Description – IAP 2005maximize [ F L – 3*D – 5*W ]Where:L measured downforce (negative lift) at specified speed [N]D measured drag at specified speed [N]W total weight of the assembly (not including test fixture) [N]The nominal speed is 60 mph16.81033

Project Deliverables – IAP 2005Phase 1Problem StatementHand SketchPhase 2Initial CADCAE (FEA)CAE (CFD)Weight (kg)Weight vs Wing Segment Angle21.91.81.71.61.51.41.31.21.1145 Degrees0Chord vs Cl: Optimal20406080100Angle (from vertical)0.60.55Max PossibleChordchord (m)0.5Performance: Expected vs Measured0.45Max Possible weightdragliftparameterDesign Optimization16.810Prototype Testing and Validation34

Optimization – 2004 & 2005Manual Iteration Design loops(Spiral method)Software Objective Function Value Formal softwareMatlab/Excel(Tradeoff Plots)CL16.810Endplate Height35

Learning from Mistakes Carrying out a full lifecycle createsmemorable learning experiencesDon’t prevent students frommaking mistakesExample: bi-wing configurationExcerpt from Student ReflectiveMemo:“I learned the value of constantly checking simulationsagainst reality . My rear-wing design used a biplanesetup, due to a huge oversight, the wings wereactually arranged in an incorrect orientation whichincurred a large drop in down force. .This experiencetaught me a great lesson – always triple check yourassumptions against your design. I spent hours andhours optimizing a design that was never constructed,simply because I was told to assume that the downforce bonus would be experienced. I never bothered toverify this myself, and this disconnection had direconsequences.”16.810-1.71.1536