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Lecture 3Dr. Khaled BakroIntroduction to Engineering DesignIntroduction to Engineering and Profession Ethics

PART 1 ENGINEERING AN EXCITING PROFESSIONEngineers, 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

OutlineOutline 1In this chapter we willIntroduce 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.

Outline Outline 2outIntroduce important design factors such asTeamworkProject schedulingMaterial selectionEconomic considerationEngineering standards and codesPresent cases studies in mechanical/ electrical engineering

objectiveThe 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.

What s 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

The Engineering Design ProcessDesign Process Basic Steps:Recognizing the need for a product or a serviceProblem definition and understandingResearch and preparationConceptualizationSynthesisEvaluationOptimizationPresentation

The Engineering Design ProcessDesign Process Basic steps (other methodology) :

Design Process Basic Steps Design Process Basic StepsStep 1 : Recognizing the need for a product or a service

Design Process Basic StepsStep 2: Problem definition and understandingThis is the most important step in any design processBefore you move on to the next step Make sure you understand the problemMake sure that the problem is well definedGood problem solvers are those who first fully understand what the problem is.

Design Process Basic StepsStep 3: Research and preparation (Project Panning)Collect useful informationSearch to determine if a product already existsPerhaps you could adopt or modify existing componentsReview and organize the information collected in a suitable manner

Design Process Basic StepsStep 4: Conceptualization ( Brainstorming)

Generate ideas or concepts that could offer reasonable solutions to your problem

Design Process Basic StepsStep 5: SynthesisAt this point you begin to consider detailsPerform 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 fabricatedConsult pertinent codesand standards for compliance

Design Process Basic StepsStep 6: EvaluationAnalyze the problem in more detailIdentify critical design parameters and consider their influence in your final designMake sure that all calculations are performed correctlyBest solution must be identified from alternativesDetails of design must be worked out fully

Design Process Basic StepsStep 7: Optimization minimization or maximizationOptimization 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

Design Process Basic Steps

An optimization procedure

Design Process Basic StepsStep 8: PresentationYou need to communicate your solution to the client, who may be your boss, another group within your company, or an outside customerEngineers 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

Other Engineering Design ConsiderationsEngineering economicsMaterial selectionTeamworkConflicts ResolutionProject scheduling and task chartEvaluating alternativesPatent, trademark, and copyrightEngineering standards and codes

Engineering EconomicsEconomic factors always play important roles in engineering design decision makingProducts that are too expensive cannot be sold at a price that consumers can afford and still be profitable to the companyProducts 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

Material SelectionSelection of materials is an important design decisionExamples of properties to consider when selecting materialsDensityUltimate strengthFlexibilityMachinabilityDurability Thermal expansionElectrical & thermal conductivityResistance to corrosion

Material PropertiesMaterial properties depend on many factorsHow the material was processedIts ageIts exact chemical compositionAny nonhomogenity or defect within the materialMaterial properties change with temperature and time as the material agesIn practice, you use property values provided by the manufacturer for design; textbook values are typical values

List of Some Material PropertiesElectrical 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

Material Properties (uid properties) Viscosity : a measure of how easily the given uid can ow. The higher the viscosity value is, the more resistance the uid offers to ow.Vapor pressure : uids with low vapor-pressure values will not evaporate as quickly as those with high values of vapor pressure.Bulk modulus of compressibility : represents how compressible the uid is. How easily can one reduce the volume of the uid when the uid pressure is increased.

TeamworkDesign 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 goalEmployers 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

Common Traits of Good TeamsSuccessful 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.

Common Traits of Good TeamsThe 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.

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 projectThe Creator good at coming up with new ideas, sharing them with other team members, and letting the team develop the ideas furtherThe Gatherer enthusiastic and good at obtaining things, looking for possibilities, and developing contacts

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 correctlyThe Team Worker tries to get everyone to come together, does not like friction or problems among team members

Secondary Roles of Good Team Members The Solver reliable and decisive and can turn concepts into practical solutionThe Finisher can be counted on to finish his or her assigned task on time; detail oriented and may worry about the teams progress toward finishing the assignment

ConflictsWhen 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

Conflict ResolutionManaging conflicts is an important part of a team dynamicIn managing conflicts, it is important to recognize there are three types of people:Accommodating CompromisingCollaborative

Conflict Resolution Type of PeopleAccommodating team members - avoid conflicts Allow assertive individuals to dominate Making progress as a whole difficultCould lead to poor team decision

Conflict Resolution Type of PeopleCompromising team membersDemonstrate moderate level of assertiveness and cooperation. By compromising, the team may have sacrificed the best solution for the sake of group unity

Conflict Resolution Collaborative Conflict Resolution ApproachHigh level of assertiveness and cooperation by the teamNo finger pointingTeam proposes solutionsMeans of evaluationCombine solutions to reach an ideal solution

Project Scheduling and Task ChartA process that engineering managers use to ensure that a project is completed on time and within the allocated budget

Evaluating AlternativesWhen a design is narrowed down to a few workable concepts, evaluation of these concepts is needed before detail design is pursuedEach design would have its own evaluation criteria

An Example of evaluation worksheet

Sustainability in DesignSustainability and sustainable engineering can be defined asdesign and development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Sustainability in Design Engineers contribute to both private and public sectors of our societyIn 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 livingIn public sector, they support local, state, and federal mission such as meeting our infrastructure needs, energy and food security, and national defense

Sustainability in DesignIncreasingly, because of worldwide socioeconomic trends, environmental concerns, and earths finite resources, more is expected of engineersFuture 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 concernsIn designing products and services, engineers must consider the link among earths finite resources, environmental, social, ethical, technical, and economical factors

SummaryYou should know the basic design steps that all engineers follow, regardless of their background, to design products and servicesYou should realize that economics plays an important role in engineering decision makingYou should realize that the selection of material is an important design decisionYou should be familiar with the common traits of good teams

Case Study

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Hyper LoopCase study in mechanical/ electrical engineering

Sport Utility Vehicle (SUV) Anti-Lock Braking System (ABS)43

Identification of ProblemWhat is required?What must be done and why?Scope of problem define problem boundaries.Example Anti-lock Braking SystemIs it possible to successfully retrofit an ABS developed for compact cars to heavier, sports utility vehicles?44

Research the ProblemCan 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

Research ABS ExampleLiterature 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

Solve the ProblemDevelop alternatives. For example;Hardware and software design alternatives.List of independent variables to vary in modeling or simulation.ModelingConceptual models.Physical models and engineering mockups.Graphical models.Mathematical models.Computer models.47

Decision Matrix48

Alternative SolutionsCriteriaEase of AssScoreScoreScoreScoreFunctionalityCostStabilityTotal ScoreWeight35%25%25%15%100%1234 5

14045125615071055205688888865773 9 9 10

175200150 45570210200125135670280200175135790280200175 150805

Solve the ProblemExperimentationComputer simulation.Testing, for example;Ground tests.Flight testing.SynthesisSubproblem solutions are merged.E.g., manufacturing and engineering resolving issues associated with manufacturability.49

Solve Problem ABS ExampleABS 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

ABS Braking Simulation Model

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Simulation Results

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Vehicle Weight = 1600lbsHydraulic Lag 0.01 sec

Simulation Results

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Vehicle Weight = 2900 lbsHydraulic Lag 0.01 sec

Simulation Results

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Vehicle speed and wheel speedSpeed(rad/sec)Time(secs)Vehicle speed (v)Wheel speed (w)Vehicle Weight = 2900 lbsHydraulic Lag 0.03 sec

Simulation Results

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Vehicle Weight = 2900 lbsHydraulic Lag 0.007 sec

Presentation56

Baseline

Best Solution

Testing - ABS

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Presentation58Is this relationship linear ornonlinear?Wt = 2900 lbs

Presentation59Wt = 2900 lbs

ResultsPerformance Criteria Satisfied.Total Time to StopRequired 15% increase over compact car.Actual 12.8% increase.Wheel Skid Lock TimeRequired 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