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CHAPTER 3
ENGINEERING SOLUTIONS
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Contents
3.1 Engineering Analysis
3.2 Problem Presentation & Organization3.3 Laboratory Report Writing
3.4 Computer Solution
3.5 Use Computers & Scientific Calculators in
Problem Solving
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Design Problem solving
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Practice of Engineering
Accumulate knowledge & experience
Use in f u
ndamental area in engineering
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Combination of1. Knowledge2. Experience3. Process
4. ArtAbility to solve technical problems (involves acombination ofart and sciences)
By science means byknowledge of the principle of
mathematics, chemistry, physics etc.
By art means the proper judgment, experience andcommon sense. the art of problem solving is a skilldeveloped with practice.
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Problem Solving
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Before the solution taken, consider the follows:
1. Howimportant is the answer to the givenproblem?
2. Would a rough, preliminary estimate besatisfactory or is a high degree of accuracydemanded?
3. How much time do you have and what
resources are at your disposal?
Problem solving is approach in a logical andorganized method, if it follows a process
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Problem Analysis
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Problem solving
Can be more efficient if it follows aprocessEngineering Method
As an example of a process! Consists of six basic steps
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Engineering Method
1. Recognize and understand the problem
2. Accumulate data and verify accuracy
3. Select appropriate theory or principal
4. Make necessary assumption
5. Solve the problem
6. Verify and Check Results
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For student normally the problem is clearIf the problem is not well defined
1. Studythe problem
2. Eliminate the things that are unimportant
3. Focusing on the root of the problem4. This can help eliminating false trial &
shortening time taken
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1. Recognize & Understand problem
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2. Accumulate data & Verify accuracy
All pertinent physical facts, such as sizes, temperature,
voltages, currents, costs, concentrations, weights, times
etc. must be ascertained
Do not mix or confuse these details with data that are
suspected or only assumed to be accurate.
Deal only with items that can be verified.
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3. Select the appropriate theory or
principal
Select appropriate theories or scientific
principles that apply to the solution of theproblem.
Understand and identify limitations or
constrains that apply to the selected theory.
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4. Make necessary assumptions
Perfect solution to real problem do not exists
Simplification and assumptions need to be made
** step no. 3 and no. 4 the order of these two
steps may be reversed
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5. Solve the problem
Solve using the application ofmathematical
theoryprovided by previous step
Trial error solution also applicable
Results normally will be in numerical form withappropriate units.
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6. Verify and Check Results
Result must be check to ensure the correctness Correctness can be verified by:
Repeat solution using different techniqueExperiment
Examined the answer whether it makes sense or
not
Units used correct units dimensionallycorrect..
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a well documentedcollected/accumulated intoproblem solution
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3.2 Problem Presentation
and Organization
Engineer must know how to translate the information
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Problem Presentation
1. Problem statement
2. Diagram
3. Theory
4. Assumptions
5. Solutions Steps
6. Identify results and verify accuracy
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1. Problem statement
State as concisely as possible the problem to be
solved.The statement should be a summary of the
given information, but must contain all essential
material.
Clearly state what is to be determined.
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2. Diagram
A picture paints a thousand words!!
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Appropriate way of illustrating the
physical setup, which may be difficult to
describe adequately in words.
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2. Diagram
Prepare a diagram with all pertinent
dimensions, flow rates, currents, voltages,
weights etc.
A veryefficient method of showing given
and needed information.
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3. Theory
Referenced equation with completely
defined variables is sufficient.
Extensive theoretical derivation may be
necessary because the appropriate theory
has to be derived, developed or modified.
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4. Assumptions
List in complete detail all assumption that
have been made to realize solution to the
problem.
Important for readers understanding of
solution and limitations.
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5. Solution steps - steps of solving theproblem
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6. Identify results and verify
accuracy
Clearly identify the final answer.
Requires that the answer be examined to
determined if it is realistic, so check
solution accuracy and if possible, verify
the results.
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Example of Problem Solution presentation
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Example of Problem Solution presentation
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LABORATORY REPORT
WRITING
AGOOD lab report does more than present data ;it demonstrates the writer's comprehensionof the
concepts behindthe data
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General Suggestions
Write a neat report. You should ensure that all
sentences are grammatically correct and that
there are no mistakes in spelling.
Organize your data in a data table.
Carryunits in all calculations.
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GUIDELINES
1. COVERPAGE
The cover page of your lab report shouldinclude:x
x
x
x
x
the name of the experiment;your instructor's name;
your name & student id ;the date the lab was performed;the lab due date or submitted.
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1. TITLE2. OBJECTIVE
The objective is the reason you are doing theexperiment.
Before you write the objective you need to knowwhyyou are doing the experiment.
The objective should be stated clearly in your ownwords.
3. EQUIPMENT
This section contains a list of the equipment that youused to perform the experiment.
When possible, draw a diagram to illustrate theapparatus. Give the make and model
number of the equipment where possible
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4. PROCEDURE
This section includes a description of what you did. You do not report
any results in this section . Explain what you did clearly enough f
other people to follow your directions to repeat the experiment. A
step by step format is the best approach.
5. RESULT & CALCULATION
This section is where measurements taken during the experimentare reported.
Data should be reported in a clear and organized way(pie chart,diagram, graph).
Calculations based on the data are presented in this section. Youneed to report all the calculations that you did. You need to provide
the formulas used to compute your results. Sample calculation.
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6. DISCUSSION
This section provide a discussion of whetheror
not you feel the errors are reasonable.It is the most important part of your report,
because here, you show that youunderstand the experiment beyond the simple
level of completing it.
Explain. Analyze. Interpret
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Analysis
What do the resultsindicateclearly?
What have you found?
Explainwhat you know with
certaintybased on yourresults .
Interpretation
What is the significanceof
the results?
What questions might we
raise?
Findlogical explanationsfor problems in the data.
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7. CONCLUSION
Conclusion can be very short .Be sure to go backand reread your objective before writing yourconclusion. This section should be concise andto the point.
Your conclusion should be tied to the objective.Was the objective for the experiment met?
State whether or not you achieved your objective.
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Computer Solutions
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COMPUTER SOLUTION
Asimple problem may require only brief
hand calculations or the use of
engineering calculator.
If the complexity of the solutions is high
or the amount of data or number of casesto be processed is large, other methodsshould be considered.
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USE COMPUTER SOFTWARE IN
ENGINEERING SOLUTIONS
Spreadsheet
Math Calculation Packages
Programming Languages
Flowcharting
Computer Aided Design (CAD)
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Spreadsheet
Example software :-
EXCEL, Lotus 123 and Quattro Pro.
Handling large quantities of data and in allowing
repetitive calculation to be done in relative ease.
Allows to store original data, computed results and
charts in electronic form that can be easily changed
at a later date if new or corrected data become
available.
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Math Calculation Packages
Example Software :-
Maple, MathCAD, Mathematica, Matlab.
Ability to perform complex mathematicalcomputations (algebra, calculus, differential
equation)
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Programming Languages
Example :-
FORTRAN, C++,Visual Basic, MATLAB
Prepare solution to certain problems
It is effective to program a solution if the
solution is a unique application or if the solutionis to be used repetitively without need for
changing the programming code.
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Flowcharting
ogic diagram to describe each step that the
program must perform to arrive at the
solution.
Apopular logic tool used for showing an
algorithm in graphics form.
Programmer prepares flowchart before
coding.
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Purpose of Flowcharting
An aid in developing the logic of aprogram.
Verification that all possible conditionshave been considered in a program.
Provides means of communication with
others about the program.Aguide in coding the program.Documentation for the program.
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Flowcharting
Most common flowchart symbols are:
Sequential structure Selection structure
Repetitive structure
ProcessesInput/Output
Choices
Three general structures:
Start / End
FlowArrow
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Example of Flowchart:
Sequential Structure
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Example of Flowchart:
Selection Structure
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Example of Flowchart:
Repetition Structure
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Computer Aided Design (CAD)
Example :-Solidworks, AutoCAD, Catia
solid 2D or 3D modelling, analysisused to produce computer animation
for special effects in movies,advertising and technical manualsbenefits :- save time for analysis
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