DESIGN
AND
ANALYSES
OF
EXPERIMENTS
Prof. Dr. Ahmed Farouk Abdul Moneim
WHY do we perform EXPERIMENTS?
In order to DEVELOP and ENHANCE
1) PRODUCTS / SYSTEMS
2) PROCESSES
HOW do we perform EXPERIMENTS?
1) PHYSICAL EXPERIMENTS
2) COMPUTER SIMULATION
DYNAMIC SYSTEMS
Mechanical Vibrations
Plane Takeoff distance
Maneuverability
Cars Braking distance
Ships and Cars Cruising Circles
Ship motions
INDUSTRIAL SYSTEMS
Inventory Control
Production
Order Quantity
Reordering Point
Probability of getting out of Stock
Line Efficiency
Flexibility
Robustness
Efficiency
MARKETING SYSTEMS
Market Share
Market Size
Customer Satisfaction
Productivity
PROCESSES
METALLURGICAL
Proper Percentage of Alloying Elements In order to achieve a specified
Property
MACHINING
Select Depth of Cut and Tool Feed for Optimum SURFACE FINISH
WELDING
Optimum WELDING SEQUENCE in order to Minimize Welding Deformations
MAINTENANCE
Decide the OPTIMUM Maintenance Policy
Determine the OPTIMUM FREQUENCY Of Preventive Maintenance
In order to Design an Experiment whether Physical or
Simulation, we have to decide at the very beginning:
1) What is
THE PERFORMANCE MEASURE
PROPERTY
OR
to be Optimized. This we call:
THE RESPONSE
2) What are
THE FACTORS
That
SIGNIFICANTLY
affect THAT RESPONSE
System / Product / Process
Response
Variables
SALES
Price
Marketing System
Factors
Promotion Mix
Distribution Channels
Response
PRODUCTIVITY
Technology utilized
Production System
Factors
Layout
Degree of Automation
Response
Stainless Steel
Factors
Response
Passenger ship
CORROSION RESISTANCE
% Nickel
% carbon
SEA WORTHINESS
Sea State: Waves height and lenght
Factors
Ship Geometry, VCG and LCG
Number of screws
STRATEGIES
OF
EXPERIMENTATION
1) ONE FACTOR-AT-A-TIME STRATEGY
 The Oldest Strategy
The Experiment is conducted in Several Runs.
In each Run ONE Factor only is changed and the others are kept
Unchanged
 The main SHORTCOMING of this strategy is that the INTERACTION of the
different Factors CANNOT be obtained
2) COMPLETE
RANDOMIZED DESIGN
3) RANDOMIZED COMPLETE
BLOCK DESIGN
LATIN SQUARE DESIGN [ Nuisance Factors]
4) COMPLETE
FACTORIAL DESIGN
5) FRACTIONAL
FACTORIAL DESIGN
METHODOLOGIES ADOPTED
IN
EXPERIMENTATION
1) REPLICATION
Experiments are repeated for the same level of factors.
2) RANDOMIZATION
Samples and test tools are selected randomly
COMPLETE RANDOMIZED DESIGN
Nuisance Factors
 Block Design
Prof. Dr. Ahmed Farouk Abdul Moneim
These are Factors influencing the Response
But
They are not of Immediate interest.
Such as
Response: Productivity of steel Cutting Processes
Factor of interest: Type of the Cutting Process with three levels
Mechanical Cutting
Oxy-Acetylene Cutting
Plasma Cutting
Nuisance Factor : Worker Skill levels
Required to SEPARATE effects of Nuisance Factors from that
of the Factors of Interest
Prof. Dr. Ahmed Farouk Abdul Moneim