Introduction To Mechanical Engineering Design PDF

CHAPTER 3 Introduction to Mechanical Engineering Design Cover:  Definition of design vs engineering design  Engineering design process  Design - a CDIO perspective  A practical example  Creativity – lateral thinking  Teamwork – building teamdynamics 3.1 The Engineering D...

CHAPTER 3 Introduction to Mechanical Engineering Design Cover:  Definition of design vs engineering design  Engineering design process  Design - a CDIO perspective  A practical example  Creativity – lateral thinking  Teamwork – building teamdynamics 3.1 The Engineering Design and Its Process What is Design?  Design is an intended-planned process of constructing or realizing something, which may be a plan, a product, a building, a device, a structure, a program, a system, and etc.  It is something that develops or begins from ideas into tangible or intangible outcomes or results. Definition (cont.): What is Engineering Design?  It is a creative, comprehensive, and iterative process of devising a system, component, or process to meet desired needs optimally.  It integrates mathematics, basic sciences, engineering sciences, engineering specialties, economy and other subjects for the creation of components, products systems, or processes to satisfy specific needs within given limitations and constraints. Definition (cont.):  i.e. limitations such as the requirements of standards, rules and legislation, and other considerations such as maintainability, serviceability, manufacturability, and availability of resources; while constraints may include economic, safety, health, environmental and social factors, and etc. Definition (cont.):  Mechanical engineering design (simply ME Design) means the design of mechanical products (and their components), or systems of a mechanical nature such as machines, mechanisms, structures, devices or instruments, robots, and etc.  Modern systems or products are very interdependent, i.e. integrated elements from other fields of engineering such as civil, electrical and electronics, chemical, computer, and other systems. Definition (continued):  Among the fundamental aspects or elements of the engineering design process are the establishment of objectives and criteria, synthesis, analysis, construction, testing, evaluation, and operate.  In October 2000, a major reform in undergraduate engineering education with regard to the design ability of an engineer, called CDIO initiative, was launched. 3.2 Engineering Design – A CDIO Perspective… CDIO Background  In January 2004, the CDIO Initiative adopted 12 standards that describe CDIO programs - “The Guiding Principles”.  It is a major international project to reform undergraduate engineering education, called The CDIO Initiative, which then has expanded to include engineering programs worldwide. CDIO Background (cont.)  The vision of the project is to provide students with an education that stresses engineering fundamentals set in the context of Conceiving--Designing--Implementing-- Operating (CDIO) real-world systems and products. Rationale of CDIO:  Beginning engineers should be able to Conceive--Design--Implement--Operate complex value-added engineering products, processes, and systems in modern team- based environments. They should be able to participate in engineering processes, contribute to the development of engineering products, and do so while working in engineering organizations. This is the essence of the engineering profession. Rationale of CDIO: (cont.)  The CDIO Initiative has three overall goals - to educate students who are able to:  master a deep working knowledge of technical fundamentals  lead in the creation and operation of new products, process, and systems  understand the importance and strategic impact of research and technological development on society Standard #4 of CDIO Initiative  Standard 4 -- Introduction to Engineering An introductory course that provides the framework for engineering practice in product, process, and system building, and introduces essential personal and interpersonal skills => MEC400 What is CDIO…? Conceive--Design--Implement—Operate  It is a framework or an environment in which students acquire the knowledge, skills, and attitudes essential to beginning engineers.  Conceiving-Designing-Implementing- Operating is a model of the entire product, process, and system lifecycle. ◦ The Conceive stage includes defining customer needs; considering technology, enterprise strategy, and regulations; and, developing conceptual, technical, and business plans. ◦ The Design stage focuses on creating the design, i.e., the plans, drawings, and algorithms that describe what will be implemented. ◦ The Implement stage refers to the transformation of the design into the product, process, or system, including manufacturing, coding, testing and validation. ◦ The Operate stage uses the implemented product or process to deliver the intended value, including maintaining, evolving and retiring the system. Summary… 3.3 Engineering design method (EDM)  The design process, known as the engineering design method (EDM) may be divided in many different ways and steps (or phases) where in each step involves a decision-making process.  EDM is an iterative and cyclic process, which is continuous and discursive in nature. Iterative Design Overview Design, Conceptual & Physical User Models & Requirement Specifications s Evaluation & Prototyping & Feedback Construction Demos & Products Engineering design method (EDM) We may divide EDM into several steps or phases as follows: 1. Phase I = Conceptual Design 2. Phase II = Embodiment Design Three major 3. Phase III = Detailed Design phases 4. Phase IV = Planning for Manufacture 5. Phase V = Planning for Distribution 6. Phase VI = Planning for Use 7. Phase VII = Planning for Retirement of product 1. Phase I - Conceptual Design Step 1 Step 2 Step 3 Step 4 Identify/Define Gather Generating Concept Problems Information concept Evaluation Prob. Statement References Brainstorming Pugh concept Benchmarking Electronic Media Functional Decision Matrix QFD Internet decomposition Taguchi Method PDS Mchart 2. Phase II - Embodiment Design Step 3 Step 2 Step 1 Parametric Configuration Product design design architecture Selection of Robust design materials and Arrangement of Set manufacturing physical tolerances,DFM, processes elements DFA,DFE Modeling Modularity Tolerances Sizing of parts Step 1 Product 3. Phase architecture iii – Detailed Design Detailed engineering drawings & PDS 3.3.1 Conceptual design phase  User Requirements => Conceptual Model  “a description of the proposed system in terms of a set of integrated ideas and concepts about what it should do, behave, and look like, that will be understandable by the users in the manner intended”  High-level of thinking process as compared to physical design  Have your timeline – A Gantt chart! Conceptual design phase - Step #1: Problem Definition  Most important steps in the engineering design process. 1. Identifying customer needs: a. Interview customers b. Focus group c. Customer survey d. Customer complaints Benchmarking – method for measuring company operation against the best company inside and outside of the industries ◦ Select the product, process, or functional area that is to be benchmark. ◦ Identify the performance metrics that will be measured and used for comparison. ◦ Compare the best in class product or process with the in house equivalent using the performance metrics ◦ Specified program and actions to meet an exceed the competition. QFD – Quality Function Deployment  A planning and problem solving tool that is finding growing acceptance for translating customer requirements into engineering characteristics of a product.  A largely graphical method that systematically looks at all the elements that go into the product definition.  Helps organizations seek out both spoken and unspoken needs.  QFD links the needs of the customer (end user) with design, development, engineering, manufacturing, and service functions.  Also known as ‘House of Quality’ PDS – Product Design Specifications  A statement of what a product to be designed is intended to do.  Its aim is to ensure the development of a product meets the need of the users.  The PDS is a specification of what is required but not the specification of the product itself. House of quality 1. Phase I - Conceptual Design Step 1 Step 2 Step 3 Step 4 Identify/Define Gather Generate Evaluate Problems Information concept Concept Prob. Statement References Brainstorming Pugh concept Benchmarking Electronic Media Functional Decision Matrix QFD Internet Decomposition Taguchi Method PDS Mopho. chart 2. Phase II - Embodiment Design Step 3 Step 2 Step 1 Parametric Configuration Product design design architecture Selection of Robust design materials and Arrangement of Set manufacturing physical tolerances,DFM, processes elements DFA,DFE Modeling Modularity Tolerances Sizing of parts Step 1 Product 3. Phase architecture iii – Detailed Design Engineering drawings Finalize PDS Conceptual design - Step #2: Gather Information Information Gathering  Information from Internet  Engineering URLs  Patent Literature  Intellectual Property  Patents  Handbook  Other sources Conceptual design - Step #3: Generate Concepts Concept Generation (Generate alternative solutions conceptually, or synthesis of a scheme i.e. the how-to)  Brainstorming  Functional decomposition  Morphological chart Step #3: (cont.)  May synthesize several components of a system, analyze and optimize them, and return to synthesis to see what effect this has on the remaining parts of the system.  For analysis and optimization, we need to construct or devise abstract models of the system, called mathematical models. Step #3: (cont.): Functional decomposition Car seat Modify car Modify Modify User’s safety Body sensor seat back rest head rest system Forward & Reclining Upward & Types Shape backward movement downward Modification Movement movement Shape movement point Upward & Modification Shape downward point Modification movement point Shape Modification Figure 3.3: Main Functional Decomposition point Step #3: (cont.): Morphological Chart Morphological chart  Chart arranges a functions and sub-functions in a logical order  Each sub-function list the possible how  Purpose to uncover combinations of ideas that comprise design concepts that might not ordinarily be generated Conceptual design - Step #4: Evaluate Concepts  Assess whether performance of each system is satisfactory or not and, if yes, just how well it will perform, if not, then revise, improve, or discard (RID). Evaluation of concepts  1. Comparison Based on Absolute Criteria  2. Pugh’s Concept Selection Method  3. Weighted Decision Matrix Criteria Concept 1 Concept 2 Concept 3 Standard Seat Seat: Mechanism with multiple rest point and smooth movement. + - - D Back rest : Comfort, easy maneuverability + S - A and adjustment Pugh’s Concept Head rest: Selection Method Adjustability, Easy movement and S - + T not bulky User Safety/Comfort: Simple, safe, comfort S - - U Detection location/point: Smooth motion and ensured + + - M stability ∑+ 3 1 1 ∑- 0 3 4 ∑S 2 1 0 Some Guiding Principles:  Discuss and get different perspectives  Prototyping  Iterate, iterate, iterate!  Consider many alternatives  “To get a good idea, get lots of ideas”  Empathize with the user  http://www2.mae.ufl.edu/designlab/lab%20a ssignments/eml2322l-design%20process.pd f  Thank you