Problem Solving Skills (SEMM 1921 PDF)

SEMM 1921 INTRODUCTION TO MECHANICAL ENGINEERING PROBLEM SOLVING SKILLS  1.3 Problem Solving Skills 1.3.1 Why Problem Solving is Impor tant? Engineers by def inition are problem solvers Whether they are involved in analytical, experimental, computational or design w...

SEMM 1921 INTRODUCTION TO MECHANICAL ENGINEERING PROBLEM SOLVING SKILLS  1.3 Problem Solving Skills 1.3.1 Why Problem Solving is Impor tant? Engineers by def inition are problem solvers Whether they are involved in analytical, experimental, computational or design work, engineers solve problems In professional practice, engineers commonly solve problems that are highly complex and open- ended Good engineering requires high-level thinking  1.3 Problem Solving Skills 1.3.1 Why Problem Solving is Impor tant? Professor Woods and his colleagues at McMaster University def ine problem solving as: "Problem solving is the process of obtaining a satisfactor y solution to a novel problem, or at least a problem which the problem solver has not seen before.“ Real world problems tend to be quite dif ferent than most exercises found in engineering textbooks Many studies have found that engineering graduates, even though they solve more than 2,500 exercises in their undergraduate work, lack the essential problem solving skills needed to tackle real world problems  1.3 Problem Solving Skills 1.3.2 Problem Approach SOLUTION YAW DRAH PROBLEM  1.3 Problem Solving Skills 1.3.2 Problem Solving Approach Wood’s MethodDESCRIPTION STEPS [2,3] 0. Engage/Motivation I can do it! I want to do it! 1. Def ine the Problem  Def ine what the problem states  Sketch the problem (if appropriate)  Determine the given information  Determine constraints  Def ine criterion for judging f inal product 2. Explore the problem  Determine the real objective of the problem  Examine issues involved  Make reasonable assumptions  Guess/estimate the answer  1.3 Problem Solving Skills 1.3.2 Problem Solving Approach STEPS Wood ’s Method 3. Plan the solution DESCRIPTION  Develop a plan to solve the problem  Map out sub-problems  Select appropriate theor y , principles, approach  Determine info that needs to be found 4. Implement the plan  Take actions  Do calculations and analysis 5. Check the solution  Units and accuracy 6. Evaluate/Ref lect  Is it reasonable? Does it make sense?  Were the assumptions appropriate?  How does it compare to initial guess/estimate?  If appropriate, ask the question: is it socially / ethically acceptable?  1.3 Problem Solving Skills 1.3.2 Problem Solving Approach Wales’s Method – Professional Decision Making Process [4,5] STEPS DESCRIPTION 1. Af firmation  Make statement(s) that promote ef fective psychological management 2. Def ine the situation  Ask questions and gather appropriate information with an intent of clarifying, interpreting, and understanding the situation 3. State the goal  Determine the appropriate or best goal or combination of goals. T h e goal should be concrete T h e goal should be presented with enough specif icity so dif ferent people would agree when the goal is reached  1.3 Problem Solving Skills 1.3.2 Problem Solving Approach Wales’s Method – Professional Decision Making STEPSProcess DESCRIPTION 4. Generate Ideas  Generate many possible ways to reach the goal  Analyze these ideas, and then select the best idea or combination of ideas 5. Prepare a plan  Carefully plan the steps needed to make the best idea a reality 6. Take action  Implement the plan 7. Review & Ref lect  Check the solution to assess quality.  Analyze the problem solving approach in order to identify what worked and what did not work  Seek ways to ref ine or improve one’s problem solving approach  Clarify what was learned during the complete experience.  1.3 Problem Solving Skills 1.3.2 Problem Solving Approach Professional Decision Making Process : An Example 5.52 Water is forced out of this nozzle by a piston moving at a speed of 5 m/s. Determine the force F required to move the piston and the speed of e ux of water from the nozzle. Neglect friction on the piston and assume irrotational flow. T he exit pressure is atmospheric; D = 6 cm and d = 2 cm. Problem 5.52; from Crowe et al. (2001)  UNIT SYSTEMS AND CONVERSIONS Engineers specify physical quantities in two di erent—but conventional—systems of units: 1) United States Customa System (USCS) 2) International System of Units (Systeme International d’Unites or SI). Practicing mechanical engineers must be conversant with both systems. ey need to conve quantities from one system to the other, and they must be able to pe orm calculations equally well in either system. 12 13 SUMMARY: Units and Conversion 14 Dimensional Consistency: Examples 15 SKMM1922: Technical Problem Solving ESTIMATION IN ENGINEERING In the earlier stages of design, engineers nearly always make approximations when solving technical problems. ose estimates are 16 made to reduce a real system, as impe ect and non-ideal as it may be, into its most basic and essential elements. Assumption (inviscid, adiabatic, isothermal and etc) Linearised Simpli ed model Bounda Conditions Unce ainties Time and Cost Examples of engineering estimation: 1. Bernoulli's Equation [assumptions: steady, inviscid and incompressible ow] 17 2. Mass-spring-damper to model vehicle suspension Variations in Engineering Quantify Variations Requirements Inconsistency Accuracy Signi cant Digits Fluctuations Tolerance Dimensional Consistency Disturbances Unce ainty Estimation in Engineering Errors Precision Statistical Probability True value Examples of variations: (1) Signi cant digits of pi (2) Dimensional Consistency Coe cient Inconsistency (Drag Coe cient) CD = Drag Force/ (Dynamic Pressure * Area) Aircraft: Area = wing area Automobile: Area = frontal area SKMM1922: Technical Problem Solving 18 (3) Variation in gravity (4) Fluctuation in data and signal measurement (Systematic Error + Random Error) Statistics: Mean, Root-Mean-Square (RMS) and Standard Deviation (Sigma) Resources  RESOURC 1. Dr. Mohd. Shuisma binES Mohd. Ismail (2011), Chairman FYE Committee, Faculty of Mechanical Engineering, UTM - Notes and Personal Communication 2. Dr. Eric P. Soulsby, University Learning Skills: A First Year Experience Orientation Course for Engineers , 29th ASEE/IEEE Frontiers in Education Conference Session 11a7-6 3. Donald F. Elger, Terr yR. Armstrong, Steven W. Beyerlein, Carlo F. Felicione, Katharine J. Fulcher, Paul W. Rousseau (2001), A Structured Problem Solving Model for Developing High-Level Skills, Proceedings of the American Society for Engineering Education Annual Conference & Exposition 4. N. J. Mour tos, N. DeJong Okamoto & J. Rhee (2004), Def ining, teaching, and assessing problem solving skills, 7th UICEE Annual Conference on Engineering Education UICEE, Mumbai, India 5. Wales, C.E., and Stager, R.A., (1990), T hinking With Equations, Center for Guided Design, West Virginia University, Morgantown, WV. 6. Woods, D.R., (2000), An Evidence-Based Strategy for Problem Solving,