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| In this
issue: |
Issue
7, September 2001 |
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Reliability HotWire
is a service of ReliaSoft
Corporation
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To remove yourself from this e-mail list: Send an e-mail with the word "REMOVE" in the
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|
| Hot Topics |
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Using
Accelerated Life Testing Analysis to Characterize "Shelf Life"
In this case
study, we take a look at how ReliaSoft's ALTA software can be utilized to
characterize the "shelf life" of certain chemicals. Most life
data or accelerated testing analyses have time as the dependent variable
and other inputs as stress factors. However, in this case, time will be
considered to be the stress factor, while the dependent variable is a
particular characteristic of the chemical, such as concentration. Through
this type of analysis, one can determine the probability that the chemical's
characteristic will be outside an acceptable range of values based on test
readings taken at various time intervals.
To
read more, see http://www.reliasoft.com/alta/a6ex6/index.htm
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| Reliability
Basics |
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| The
purpose of this section is to offer background and advice to the novice
reliability engineer.
The Reliability Function
The most frequently used function in life data analysis and reliability
engineering is the reliability function. This function gives the
probability of an item operating for a certain amount of time without
failure. As such, the reliability function is a function of time, in that
every reliability value has an associated time value. In other words, one
must specify a time value with the desired reliability value, i.e. 95%
reliability at 100 hours. This degree of flexibility makes the reliability
function a much
better reliability specification than the MTTF, which represents only one
point along the entire reliability function.
In this article, we will take a look at the reliability function, how
it is derived, and an elementary statistical background.
To read more, see http://weibull.com/hotwire/issue7/relbasics7.htm
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| Tool
Tips |
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The
Tool Tips section addresses helpful hints and frequently asked questions
about ReliaSoft software products.
-
How do I remove the
Program ID from the plots in Weibull++ and ALTA?
-
Is there a quick
way to specify stress profiles in ALTA 6 PRO?
-
Can I have circular
references in my RBD in BlockSim?
To read more, see http://weibull.com/hotwire/issue7/tooltips7.htm
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| Hot
News |
|
 Sold
Out Reliability Seminar - We
want to express our appreciation to everyone who attended the sold
out "Master the Subject, Master the Tools"
reliability training seminar in San Diego, California last
week. Thanks for your participation!
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|
BlockSim
MT for the Machine Tool Industry
- ReliaSoft has been working closely with Ford Motor
Company and their machine tool suppliers to develop a customized
version of BlockSim. BlockSim MT, which was released earlier this
month, was designed to provide an easily understandable standardized
R&M report, including an Operational Availability Tree for
machine tool equipment.
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Next
Seminar in Tucson, October 15 - 19 - The next ReliaSoft
"Master the Subject, Master the Tools"
reliability training seminar will be
held October 15 - 19, 2001 in Tucson, Arizona at the Sheraton Hotel
and Suites. Topics for this five-day seminar include life data
analysis, accelerated life testing data analysis, and system
reliability, maintainability and availability. For more information on
course content and how to register, see http://Seminars.ReliaSoft.com.
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| |
QALT Boot
Camp -
ReliaSoft will begin offering an intensive three-day course on
advanced topics, concepts and applications of quantitative
accelerated life testing (QALT) with its "QALT Boot
Camp." This is a three-day seminar that covers advanced
topics in accelerated life test data analysis such as time-varying stresses
and multiple stress testing. The next QALT Boot Camp will be held in
Tucson, Arizona on November 14 - 16, 2001 (New dates!). For more information on
course content and how to register, see http://Seminars.ReliaSoft.com/qalt.htm. |
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| From
the Edge |
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|
Every
quarter, ReliaSoft publishes Reliability Edge, a printed journal
that includes articles and information related to the field of
reliability engineering. Articles of interest in the current edition:
- Using Degradation Data for Life Data Analysis - One of the
obstacles to performing a complete life data test is the amount of
time it may incur. Given reduced development cycle time and
increased product reliability, it may be unrealistic to run test
units to failure in a timely fashion.
The analysis of
degradation data is one way to overcome this obstacle. Degradation
analysis involves the measurement of the degradation of a product,
where the degradation can be directly related to the expected failure
of the product. This information is then used to estimate the eventual
failure time for the product. See http://www.ReliaSoft.com/newsletter/2q2001/degradation.htm.
- Classic Case Studies in Reliability Analysis: The Weibull
Distribution - It has been exactly 50 years since Professor
Walloddi Weibull published his groundbreaking paper, "A
Statistical Distribution Function of Wide Applicability," in
the Journal of Applied Mechanics. The 1951 paper contained seven
case studies. This article revisits
the first of these examples using modern computer tools.
See
http://www.ReliaSoft.com/newsletter/2q2001/classic_weibull.htm.
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Contribute
to Hotwire
|
Contributions Welcome
As always, your
feedback and contributions are appreciated. ReliaSoft is able to provide the most
user-friendly reliability software packages and support because we
listen to our customers. This applies to our newsletters and
publications as well. We welcome any suggestions or contributions you may
have for Reliability HotWire.
If you have a topic or
article that you think would be useful to the readers of Reliability
HotWire, feel free to contact us. We can be reached by
e-mail at HotWire@ReliaSoft.com,
or by standard mail at 1450 S. Eastside Loop, Tucson, AZ 85710-6703, USA.
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Copyright © 2001 ReliaSoft
Corporation, ALL RIGHTS RESERVED
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