ME 303 PRINCIPLES OF CAE ASST.PROF.DR.HASAN HACIŞEVKİ

Reverse Engineering:

What is Reverse Engineering?  It is a systematic methodology for analyzing the design of an existing device or system, either as an approach to study the design or as a prerequisite for re-design.

Reverse Engineering helps you to:  Develop a systematic approach to thinking about the engineering design of devices and systems  Acquire a mental data bank of mechanical design solutions

Levels of Analysis in Reverse Engineering  System-Wide Analysis  Subsystem Dissection Analysis  Individual Component Analysis

System-Wide Analysis  Customer Requirements  Engineering Requirements  Functional Specifications  Prediction of Subsystems and Components

Subsystem Dissection Analysis  Document Disassembly  Define Subsystems  Determine Subsystem Functional Specifications  Determine Subsystem Physical/Mathematical Principles

Individual Component Analysis  Repeat Dissection Steps to Individual Component  Define Component Material Selection and Fabrication Process  Suggest Alternative Designs, Systems, Components, and Materials

Example: Ten-Speed Bicycle Customer's Perspective: Provide transportation at moderate speeds, with reasonable comfort, safety, and reliability, without excessive effort, and at an affordable cost. Engineer's Perspective: Transportation of one individual and cargo weighing up to XX pounds, dimensions not to exceed A x B x C, with max speed up to YY mph on level or concrete pavement, sustainable speed of ZZ mph for up to 3 hours, etc.

Functional Requirements  Required Speed: affected by weight, gearing, tire size, tire design, frame design, streamlining.  Controllability: affected by handle bar position, dimensions, brake grip design, front tube angle  Safety:  Braking Capability affected by brake materials and design.  Tire Puncture affected by tire materials, tire construction, tire pressure.  Structure affected by frame material, thickness, welding, frame design.  Visibility: affected by finish, accessories, lights, reflectors.

Functional Requirements (cont.)  Ergonomics:  Riding Comfort affected by seat shape, size, material, positioning, adjustability, suspension, frame size.  Steerability affected by handlebar location and shape, dimensions.  Braking affected by design of brake handgrip, calipers, leverage.  Power Delivery affected by frame size, crankset dimensions, gearing, gearshift location, size, and type.  Economics: ΩInitial Cost affected by materials, complexity, number of parts, manufacturing methods, sales volume. ΩMaintenance Cost affected by tire materials, brake materials, durability of components, complexity of subsystem design.

Dissection: Subsystem Level Bike Define Subsystems  Frame  Seat  Steering, including handlebar and fork  Wheels, including hubs, spokes, rim, and tires  Power Input, including crankset and foot pedals  Power Transmission, including front and rear deraileurs, gears, gear shift levers, and chain  Brakes, including brake pads, calipers, cables, and handgrips

Example Reverse Engineering Items o Bathroom Scale o Bicycle Pump o Can Opener o Deadbolt Lock o Desktop Clamp o Doorknob Assembly o Flashlight o Hand Tool o Hose Nozzle o Kitchen Timer o Model Car Drive Train o Pencil sharpener o Pepper Grinder o Piston Assembly o Pipe Clamp o Shower Massage Head o Sprinkler Head o Stapler o Toy Car o Toy Gun