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Mechanical Engineering Systems Design

Mechanical Engineering Systems Design. Eng. R. L. Nkumbwa Copperbelt University, 2010 Zambia. Who is a ‘Mechanical Engineer’?.

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Mechanical Engineering Systems Design

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  1. Mechanical Engineering Systems Design Eng. R. L. Nkumbwa Copperbelt University, 2010 Zambia

  2. Who is a ‘Mechanical Engineer’? • Mechanical Engineers are associated with the production and processing of energy and with providing the means of production, the tools of transportation and the techniques of automations. (Shigley, 2004). Friday, August 8, 2014 Eng Nkumbwa @ CBU 2

  3. Mechanical Engineering Design • Mechanical Engineering Design involves all the disciplines of mechanical engineering including; mechanics of fluids and solids, manufacturing processes, mass and solids, momentum transfer and electrical and information technology theory. Friday, August 8, 2014 Eng Nkumbwa @ CBU 3

  4. Design Process Elements • To understand the total design process, answering the following questions may help us understand how design proceeds: • How does it begin? • Does the Engineer simply sit down at a desk with a plunk sheet of paper and fold down some ideas? • What happens next? • What factors influence the decision making? • How does the design process ends? Friday, August 8, 2014 Eng Nkumbwa @ CBU 4

  5. Eng Nkumbwa @ CBU

  6. Complete Design Process Phases Friday, August 8, 2014 Eng Nkumbwa @ CBU 6

  7. Design Process Example Eng Nkumbwa @ CBU

  8. Complete Design Process Phases • The process begins with recognition of a need and a decision to do something about it. • After many iteration, the process ends with the presentation of the plans for satisfying the need. • Depending on the nature of the design task, general design phases may be repeated through the life cycle of the product, from inception to termination. Friday, August 8, 2014 Eng Nkumbwa @ CBU 8

  9. Steps of the Design Process • Recognition and Identification: • Sometimes but not always, design begins when someone recognizes a need and decides to do something about it. • Recognition of a need and phrasing the need often constitute a highly creative act, because a need may be only a vague dissatisfaction, a feeling of uneasiness or a sensing that something is not right. Friday, August 8, 2014 Eng Nkumbwa @ CBU 9

  10. Steps of the Design Process • Definition of the Problem: • This must include all the specifications for the object that is to be designed. • The specifications are the input and output quantities, the characteristics and dimensions of the space the object must occupy and all the limitations on the quantities. • The specifications define the cost, the number to be manufactured, the expected life, the range, the operating temperature and the reliability. Friday, August 8, 2014 Eng Nkumbwa @ CBU 10

  11. Steps of the Design Process • Synthesis of a scheme connecting possible system elements is sometimes called the “Invention of the Concept”. • This is the first step in the synthesis task. Friday, August 8, 2014 Eng Nkumbwa @ CBU 11

  12. Steps of the Design Process • Research and Make Notes about: • Analysis and Optimization • Evaluation • Presentation Friday, August 8, 2014 Eng Nkumbwa @ CBU 12

  13. Design Considerations • Sometimes the strength required of an element in a system is an important factor in the determination of the geometry and the dimensions of the element. • In such a situation we say that strength is an important design consideration. Friday, August 8, 2014 Eng Nkumbwa @ CBU 13

  14. Design Considerations • When we say design consideration we are referring to some characteristics that influence the design of the element or perhaps the entire system. • Usually quite a number of such characteristics must be considered in a given design situation. Friday, August 8, 2014 Eng Nkumbwa @ CBU 14

  15. Important Design Considerations • Functionality • Strength / Stress • Distortion / Deflection / Stiffness • Wear • Corrosion • Safety • Reliability • Manufacturability • Utility • Cost Friday, August 8, 2014 Eng Nkumbwa @ CBU 15

  16. Important Design Considerations • Friction • Weight • Life • Volume • Liability • Lubrication • Noise • Styling (Aesthetics) • Shape Friday, August 8, 2014 Eng Nkumbwa @ CBU 16

  17. Important Design Considerations • Size • Control • Thermal Properties • Surface • Marketability • Maintenance • Re-Manufacturing / Resource Recovery • Energy Consumption Friday, August 8, 2014 Eng Nkumbwa @ CBU 17

  18. Important Design Considerations • Some of these factors have to do directly with the dimensions, the materials, the processing and the joining of the element of the system, and it should be noted that, throughout this design course, we will be giving attention to these factors. Friday, August 8, 2014 Eng Nkumbwa @ CBU 18

  19. Design Cost Profile Eng Nkumbwa @ CBU

  20. Design Changes & Time Used Eng Nkumbwa @ CBU

  21. Wrap-Up • How is Design Course - so far? • Any feedback please… • References as outlined in the Syllabus Friday, August 8, 2014 Eng Nkumbwa @ CBU 21

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