More Related Content


More from Dr. Khaled Bakro(20)


Introduction to Engineering and Profession Ethics Lecture3-Introduction to Engineering Design-Dr.Khaled Bakro د. خالد بكرو

  1. Lecture 3 Dr. Khaled Bakro Introduction to Engineering Design Introduction to Engineering and Profession Ethics
  2. PART 1 – ENGINEERING —— AN EXCITING PROFESSION Engineers, regardless of their backgrounds, follow certain steps when designing the products and services we use in our every day lives. 3- Introduction to Engineering Design
  3. Outline Outline 1 In this chapter we will • Introduce you to the engineering design process. • Discuss the basic steps that most engineers follow when designing a product. • Discuss the importance of considering sustainability in design.
  4. Outline Outline 2out • Introduce important design factors such as  Teamwork  Project scheduling  Material selection  Economic consideration  Engineering standards and codes • Present cases studies in mechanical/ electrical engineering
  5. objective The main objective of this chapter is: To introduce the steps engineers follow to successfully design products or provide services that we use in our everyday lives.
  6. What ıs Engineering Design?  Engineering Design is a process of devising a system, component, or process to meet a desired need.  It is a decision-making process, often iterative, in which the basic sciences, mathematics, and engineering sciences are applied to convert resources to meet a stated objective.  Structured problem-solving activity
  7. The Engineering Design Process Design Process – Basic Steps: 1. Recognizing the need for a product or a service 2. Problem definition and understanding 3. Research and preparation 4. Conceptualization 5. Synthesis 6. Evaluation 7. Optimization 8. Presentation
  8. The Engineering Design Process Design Process –Basic steps (other methodology) :
  9. Design Process – Basic Steps Design Process – Basic Steps  Step 1 : Recognizing the need for a product or a service
  10. Design Process – Basic Steps Step 2: Problem definition and understanding • This is the most important step in any design process • Before you move on to the next step  Make sure you understand the problem  Make sure that the problem is well defined • Good problem solvers are those who first fully understand what the problem is.
  11. Design Process – Basic Steps Step 3: Research and preparation (Project Panning) • Collect useful information  Search to determine if a product already exists  Perhaps you could adopt or modify existing components  Review and organize the information collected in a suitable manner
  12. Design Process – Basic Steps Step 4: Conceptualization ( Brainstorming) Generate ideas or concepts that could offer reasonable solutions to your problem
  13. Design Process – Basic Steps Step 5: Synthesis • At this point you begin to consider details • Perform calculations, run computer models, narrow down the type of materials to be used, size the components of the system, and answer questions about how the product is going to be fabricated • Consult pertinent codes and standards for compliance
  14. Design Process – Basic Steps Step 6: Evaluation • Analyze the problem in more detail • Identify critical design parameters and consider their influence in your final design • Make sure that all calculations are performed correctly • Best solution must be identified from alternatives • Details of design must be worked out fully
  15. Design Process – Basic Steps Step 7: Optimization – minimization or maximization • Optimization is based on some particular criterion such as cost, strength, size, weight, reliability, noise, or performance. • Optimizing individual components of an engineering system does not necessarily lead to an optimized system
  16. Design Process – Basic Steps An optimization procedure
  17. Design Process – Basic Steps Step 8: Presentation • You need to communicate your solution to the client, who may be your boss, another group within your company, or an outside customer • Engineers are required to give oral and written progress reports on a regular basis to various groups; consequently, presentation could well be an integral part of many other design steps
  18. Other Engineering Design Considerations • Engineering economics • Material selection • Teamwork • Conflicts Resolution • Project scheduling and task chart • Evaluating alternatives • Patent, trademark, and copyright • Engineering standards and codes
  19. Engineering Economics • Economic factors always play important roles in engineering design decision making • Products that are too expensive cannot be sold at a price that consumers can afford and still be profitable to the company • Products must be designed to provide services not only to make our lives better but also to make good profits for the manufacturer More in Chapter 20
  20. Material Selection • Selection of materials is an important design decision • Examples of properties to consider when selecting materials  Density  Ultimate strength  Flexibility  Machinability  Durability  Thermal expansion  Electrical & thermal conductivity  Resistance to corrosion
  21. Material Properties • Material properties depend on many factors  How the material was processed  Its age  Its exact chemical composition  Any nonhomogenity or defect within the material • Material properties change with temperature and time as the material ages • In practice, you use property values provided by the manufacturer for design; textbook values are typical values
  22. List of Some Material Properties • Electrical resistivity : a measure of resistance of material to flow of electricity. • Density : : how compact the material is for a given volume. • Modulus of Elasticity : how easily material will stretch or shorten. • Modulus of Rigidity : a measure of how easily a material can be twisted or sheared. • Modulus of resilience : a mechanical property of a material that shows how effective the material is in absorbing mechanical energy without going through any permanent damage. • Modulus of toughness : a mechanical property of a material that indicates the ability of the material to handle overloading before it fractures. • Thermal expansion : the change in the length of a material that would occur if the temperature of the material is changed. • Thermal conductivity : how good the material is in transferring thermal energy . • Heat capacity : represents the amount of thermal energy required to raise the temperature of one kilogram mass of a material by one degree Celsius. Materials with large heat capacity values are good at storing thermal energy
  23. Material Properties (fluid properties) • Viscosity : a measure of how easily the given fluid can flow. The higher the viscosity value is, the more resistance the fluid offers to flow. • Vapor pressure : fluids with low vapor-pressure values will not evaporate as quickly as those with high values of vapor pressure. • Bulk modulus of compressibility ‫الحجم‬ ‫معامل‬‫ل‬‫النضغاطية‬ : represents how compressible the fluid is. How easily can one reduce the volume of the fluid when the fluid pressure is increased.
  24. Teamwork • Design team a group of individuals with complementary expertise, problem solving skills, and talent who are working together to solve a problem or achieve a common goal • Employers are looking for individuals who not only have a good grasp of engineering fundamentals but who can also work well with others in a team environment
  25. Common Traits of Good Teams Successful teams have the following components: • The project that is assigned to a team must have clear and realistic goals. These goals must be understood and accepted by all members of the team. • The team should be made up of individuals with complementary expertise, problem solving skills, background, and talent. • The team must have a good leader.
  26. Common Traits of Good Teams • The team leadership and the environment in which discussions take place should promote openness, respect, and honesty. • The team goals and needs should come before individual goals and needs.
  27. Secondary Roles of Good Team Members • The Organizer – experienced and confident; trusted by members of the team and serves as a coordinator for the entire project • The Creator – good at coming up with new ideas, sharing them with other team members, and letting the team develop the ideas further • The Gatherer – enthusiastic and good at obtaining things, looking for possibilities, and developing contacts
  28. Secondary Roles of Good Team Members • The Motivator – energetic, confident, and outgoing; good at finding ways around obstacles . • The Evaluator – intelligent and capable of understanding the complete scope of the project; good at judging outcomes correctly • The Team Worker – tries to get everyone to come together, does not like friction or problems among team members
  29. Secondary Roles of Good Team Members • The Solver – reliable and decisive and can turn concepts into practical solution • The Finisher – can be counted on to finish his or her assigned task on time; detail oriented and may worry about the team’s progress toward finishing the assignment
  30. Conflicts When a group of people work together, conflicts sometimes arise. Conflicts could be the result of • Miscommunication • Personality differences • The way events and actions are interpreted by a member of a team
  31. Conflict Resolution • Managing conflicts is an important part of a team dynamic • In managing conflicts, it is important to recognize there are three types of people:  Accommodating  Compromising  Collaborative
  32. Conflict Resolution – Type of People • Accommodating team members - avoid conflicts  Allow assertive individuals to dominate  Making progress as a whole difficult  Could lead to poor team decision
  33. Conflict Resolution – Type of People • Compromising team members Demonstrate moderate level of assertiveness and cooperation. By compromising, the team may have sacrificed the best solution for the sake of group unity
  34. Conflict Resolution • Collaborative Conflict Resolution Approach  High level of assertiveness and cooperation by the team  No finger pointing  Team proposes solutions  Means of evaluation  Combine solutions to reach an ideal solution
  35. Project Scheduling and Task Chart  A process that engineering managers use to ensure that a project is completed on time and within the allocated budget
  36. Evaluating Alternatives • When a design is narrowed down to a few workable concepts, evaluation of these concepts is needed before detail design is pursued • Each design would have its own evaluation criteria
  37. An Example of evaluation worksheet
  38. Sustainability in Design Sustainability and sustainable engineering can be defined as “design and development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
  39. Sustainability in Design • Engineers contribute to both private and public sectors of our society • In private sector, they design and produce the goods and services that we use in our daily lives to allow us to enjoy a high standard of living • In public sector, they support local, state, and federal mission such as meeting our infrastructure needs, energy and food security, and national defense
  40. Sustainability in Design • Increasingly, because of worldwide socioeconomic trends, environmental concerns, and earth’s finite resources, more is expected of engineers • Future engineers are expected to design and provide goods and services that increase the standard of living and advance health care, while addressing serious environmental and sustainability concerns • In designing products and services, engineers must consider the link among earth’s finite resources, environmental, social, ethical, technical, and economical factors
  41. Summary • You should know the basic design steps that all engineers follow, regardless of their background, to design products and services • You should realize that economics plays an important role in engineering decision making • You should realize that the selection of material is an important design decision • You should be familiar with the common traits of good teams
  42. Case Study 42 Hyper Loop Case study in mechanical/ electrical engineering
  43. Sport Utility Vehicle (SUV) Anti-Lock Braking System (ABS) 43
  44. Identification of Problem • What is required? • What must be done and why? • Scope of problem – define problem boundaries. • Example – Anti-lock Braking System – Is it possible to successfully retrofit an ABS developed for compact cars to heavier, sports utility vehicles? 44
  45. Research the Problem • Can we decompose the problem into easily managed subproblems? • This step defines, for example; – Literature review for similar problems and solutions to those problems. – Relevant analytical and modeling techniques. – Testing requirements. – Design constraints. – Resource requirements and allocation. – Project schedule. 45
  46. Research – ABS Example • Literature search; Internet search on ABS. • Constraints (example); – Retain compact car ABS system architecture. – SUV ABS costs cannot exceed 110% of current compact car ABS system cost. – Time to market – 3 months. – Performance criteria; • SUV Total Time to Stop  15% increase over compact car. • SUV Wheel Lock Skid Time  10% increase over compact car. • Approach: – Develop MATLAB model of ABS system. – Parametric analysis using model. – Modify system constants. 46
  47. Solve the Problem • Develop alternatives. For example; – Hardware and software design alternatives. – List of independent variables to vary in modeling or simulation. • Modeling – Conceptual models. – Physical models and engineering mockups. – Graphical models. – Mathematical models. – Computer models. 47
  48. Decision Matrix 48 Alternative Solutions Criteria Ease of Ass Score Score Score Score Functionality Cost Stability Total Score Weight 35% 25% 25% 15% 100% 1 2 3 4 5 140 4 5 125 6 150 7 105 520 5 6 8 8 8888 6 5 7 7 3 9 9 10 175 200 150 45 570 210 200 125 135 670 280 200 175 135 790 280 200 175 150 805
  49. Solve the Problem • Experimentation – Computer simulation. – Testing, for example; • Ground tests. • Flight testing. • Synthesis – Subproblem solutions are merged. – E.g., manufacturing and engineering resolving issues associated with manufacturability. 49
  50. Solve Problem – ABS Example • ABS hardware and system architecture fixed with exception of interface to SUV. • Control software can be modified. • Matlab simulation. • Skid pad testing to verify simulation results. • Presentation of results to Product Development Team. 50
  51. ABS Braking Simulation Model 51
  52. Simulation Results 52 Vehicle Weight = 1600lbs Hydraulic Lag – 0.01 sec
  53. Simulation Results 53 Vehicle Weight = 2900 lbs Hydraulic Lag – 0.01 sec
  54. Simulation Results 54 0 2 4 6 8 10 12 14 16 18 0 10 20 30 40 50 60 70 80 Vehicle speed and wheel speed Speed(rad/sec) Time(secs) Vehicle speed ( v ) Wheel speed ( w ) Vehicle Weight = 2900 lbs Hydraulic Lag – 0.03 sec
  55. Simulation Results 55 Vehicle Weight = 2900 lbs Hydraulic Lag – 0.007 sec
  56. Presentation 56 Baseline Best Solution
  57. Testing - ABS 57
  58. Presentation 58 15.40 15.60 15.80 16.00 16.20 16.40 16.60 0.007 0.01 0.03 TotalTimetoStop(sec) Hydraulic System Time Constant (sec) TTS vs. Hydraulic Time Constant Is this relationship linear or nonlinear? Wt = 2900 lbs
  59. Presentation 59 0.00 0.50 1.00 1.50 2.00 2.50 0.007 0.01 0.03 WheelLockSkidTime(sec) Hydraulic System Time Constant (sec) Wheel Lock Skid Time vs. Hydraulic Time Constant Wt = 2900 lbs
  60. Results • Performance Criteria Satisfied. • Total Time to Stop – Required – 15% increase over compact car. – Actual – 12.8% increase. • Wheel Skid Lock Time – Required – 10% increase over compact car. – Actual – 0% increase over compact car. • Time to market – 1.5 months for S/W revisions. • Cost – Less than a 2% increase. 60