Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

3.4 Analysis and Design I

Dr. Tarek A. Tutunji

Philadelphia University

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Preview The 2nd and 3rd steps in the design process, Gathering

Information and Proposing Solutions , was presented in the previous sequence.

In this sequence, the 4th step in the design process, Study Solutions will be presented.

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Seven Design Steps1. Define the Problem2. Gather Information3. Propose Solutions

4. Study the Solutions

5. Analyze and Design the chosen solution6. Implement the Design7. Evaluate Performance

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Study the Solutions Evaluate all the proposed designs detailing the strengths

and weaknesses

The study/analysis is composed of Feasibility Study Eliminate ideas without consuming time

Preliminary Design General design

Choose a Solution (Design) Might need to re-visit the design objective

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Feasibility Study Analyze each potential solution

Use simple calculations and heuristics

Choose the best solution (s) Not possible to investigate all initial solutions in details

Consider Cost, Time, and Difficulty

Eliminate some solutions

Develop a rating scheme

Select a few of the initial solutions

Document the solutions

Communicate solutions with management

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Example: Problem Statement A company product is packaged into two different size

boxes. It already has an automated packaging system, but is running into delays during the manual sorting of the boxes. Therefore, it is required to sort the boxes according to their sizes automatically.

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Example: Sketch Problem

Box ABox B

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Example: Proposed Solutions Add another production line

Sort the boxes on another station

Add two sub-belts

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Feasibility

Solution Quick Analysis

Add another production line Too expensive

Sort on another station Time consuming

Add sub-belts Works well

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Example: Sketch

Box

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Proposed Sensors / Feasibility Weight

Image

Light

Sensor Type Quick Analysis

Weight Works, but might need more circuit functions

Image Too expensive

Light Works well

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Light Sensors to measure size

Box ABox B

Transmitters Receivers

If only one signals is OFF Box A

If both signals are OFF Box is B

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Actuator Mechanism / Feasibility Vertical arm (from the top)

Sliding Door (from the bottom)

Push arm

Swing arm

Mechanism Quick Analysis

Vertical Arm Complicated

Up-sliding Door Complicated and Expensive

Push arm Might cause damage

Swing Arm Works Well

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Example: Sketch

Box

Sensor

Actuator 1 Actuator 2

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Preliminary Design Analyze each potential solution Use calculations

Choose the best solution List advantages and disadvantages of each solution

Use evaluation matrix

A single solution will emerge here

Document the solutions Write report

Communicate solutions with management Give oral presentation

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Type of Actuators Pneumatic

Hydraulic

Electrical

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Pneumatic Actuators Low cost

High reliability

Need piping and installation

Compressibility of air

Poor performance at low speed

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Hydraulic Actuators Large Force

High Power applications

Maintenance is needed (such as oil filteration)

Hazard if leaks occur

Need

Flow and Pressure valves

Pump and Tank

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Electric Motors Accurate control

Reliable

Widely used

Easy to maintain

Variable cost depending on the application

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Actuator TypeType Grade Pneumatic Hydraulic Electric

Cost 30 Good (25) Fair (20) Very Good (27)

Reliability 30 Good (25) Fair (20) Good (25)

Complexity 20 Good (16) Fair (14) Very Good (18)

Safety 20 Very Good (18) Fair (14) Very Good (18)

Total Score 100 84 68 88

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

Conclusion Design can be divided into seven-steps

The 4th step, study solutions, was described in this sequence

This includes Feasibility Study and Preliminary Design