Presentation 1 Final Reliability
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Transcript of Presentation 1 Final Reliability
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8/2/2019 Presentation 1 Final Reliability
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AKRAM H MOH MOAMER GS28368
RELIABILITY SYSTEMS
EMM5614 MAINTENANCE MANUFACTURINGMANAGEMENT
PROF.MADYA DR.TANG SAI HONGBY
AKRAM H. MOH. MOAMER GS28368
ANAS AHMED EL-HAG GS29898
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Reliability Definition
Reliability is a time dependent characteristic.
Reliability of a system is theprobability that the
given system will perform its required function
under specified conditions for a specified periodof time.
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Reliability for different configurations
1. Series Configuration
Overall reliability = Ro = R1 * R2 * R3. Rn
R1 R2 R3 Rn
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Series Configuration
If one subsystems component fails, theoverall system will fail.
Reliability in series system decreases when it
has more subsystems.
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Example of series system reliability
If a System with two Subsystems ( eachSubsystem works 85% of tested reliability) the
reliability of it will be :R Sys= R Subsys1 x RSubsys2 =0.85 x 0.85 = 0.772
but if the system with three Subsystems ofthe same reliability the reliability will be:
R Sys = R Subsys1 x R Subsys2 x R Subsys3 = 0.85 x0.85 x 0.85 = 0.615
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Reliability in series chart
Average Reliability of all Components (Percent)
Reliabili
tyoftheSystem(
Percent)
100
80
60
40
20
0100 99 98 97 96
n=1
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Example - Communications System
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Example - Communications System
Suppose we are concerned about the
reliability of the controller, server and
transformer. Assume that these components
are independent, and that
R controller =0.95
R server =0.96
R transformer =0.99
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Example - Communications System
Since these three components connect in
series, the system A consisting of these
components has reliability:-
R system A
= P controller P server P transformer
=0.95*0.96*0.99=0.90
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Reliability for different configurations
2. parallel Configuration
Rs = 1 (1 R1)(1-R2)..(1-Rn)
R1
R2
Rn
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parallel Configuration
Reliability in parallel system increases when it
have more subsystems
If one component fail , the performance of
system will decrease.
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Example of parallel system reliability
If a System with two Subsystems (each
Subsystem works 85% of tested reliability) the
reliability of it will be: R Sys= 1-{(1-R Subsys1) x (1-R Ssubsys2)
=1-{(1-0.85) x (1-0.85)} =0.9775
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Importance of reliability
Reputation. A company's reputation is very closelyrelated to the reliability of its products. The morereliable a product is, the more likely the company is to
have a favorable reputation.
Customer Satisfaction. While a reliable product maynot dramatically affect customer satisfaction in apositive manner, an unreliable product will negativelyaffect customer satisfaction severely. Thus highreliability is a mandatory requirement for customersatisfaction.
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Importance of reliability
Warranty Costs. If a product fails to perform itsfunction within the warranty period, the replacementand repair costs will negatively affect profits, as well asgain unwanted negative attention.
Competitive Advantage. Many companies will publishtheir predicted reliability numbers to help gain anadvantage over their competitors who either do notpublish their numbers or have lower numbers.
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Reliable Brands- Laptops
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Reliable Brands- Laptops
http://www.pcworld.com/article/211402/reliability_and_service_laptops.html
http://www.pcworld.com/article/211402/reliability_and_service_laptops.htmlhttp://www.pcworld.com/article/211402/reliability_and_service_laptops.html -
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Reliable Brands-Cars
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Reliable Brands-Cars
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Importance of reliability
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Improving Reliability
Companies can improve their products by applying or improvingthese steps:
Component design: the right design for the component canenhance reliability.
Testing: testing reliability in different modes , different times ,different atmospheres will lead to improve the product and thereliability.
Redundancy/backups: thats mean system can work more thanone way , backup solution also improve the reliability
Preventive maintenance procedures: reliability improvementincrease with the preventive maintenance implementation.
User education: when the product users train or educate for howto use the product professionally thats will raise the reliability ofthe product.
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Reliability Standards
There are numerous standards for devicereliability.
activities have increased recently toward theadoption of international standards from theviewpoint of eliminating import-export barriersand technical obstacles for international trade.
standardization committees both domesticallyand in the U.S. and Europe, and promotesvigorous standardization activities.
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Reliability Standards
organizations
ISO International Standard Organization
JIS Japanese Industrial Standard
BS British Standard
MIL Military Standard ( U.S department of defense)
RCJ Reliability Center for Components of Japan
ANSI American National Standards Institute
CEN Comite Europen de Normalisation
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THANK YOU