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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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