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The first, and still the only,
commercially available software package designed expressly for quantitative
accelerated life testing data analysis, ReliaSoft's
ALTA software provides an intuitive
and user-friendly way to utilize tremendously complex and powerful
mathematical models. The software provides the life-stress relationships
required to analyze accelerated life test data with up to 8 simultaneous
stress types where stress is constant or varies with time!
When you apply quantitative
accelerated life data analysis principles and use the ALTA software
for analysis, you can significantly reduce
test times, resulting in faster
time to market, lower product
development costs, lower warranty
costs and other benefits.
We have compiled some case studies to demonstrate the
types of analyses that you will be able to perform with this powerful new
software. These are actual case studies1
that demonstrate how the analysis was handled utilizing the ALTA software.
You can download the ALTA
files (*.ralp) for all of the following case studies to follow along
with the steps.
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Case Study 1:
Voltage Step-Stress |
Description
An electronic component is subjected to a voltage stress, in
stepwise increments. The objective of this study is to determine
the B(10) life and the mean life (often called "mean time to
failure," MTTF or MTBF) of these components at the normal use
stress level.
Review Study...
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Case Study
2:
Accelerated Demonstration Test |
Description
An
electronic component is put on an accelerated test using three
different (constant) temperature stress levels with the objective of
demonstrating B(10) life with a specified confidence level. In this
study, the activation energy and acceleration factors are also
computed.
Review Study...
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Case Study
3:
Accelerated Degradation Analysis |
Description
A
chemical solution (e.g. ink formulation, medicine, etc.) that
degrades with time is studied. A quantitative measure of the quality
of the product is utilized and that measure is tracked through an
accelerated degradation scheme over time to determine the shelf life
of the product. The product is considered failed (or out of
compliance) if that quantitative measure falls below a certain
value. In this study, although none of the specimens fail, data
concerning their degradation is utilized for subsequent analysis.
Review Study...
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Case Study
4:
Automotive Part Test |
Description
Multiple stresses are applied simultaneously to a particular
automotive part in a step-stress method. In this scenario, the
stresses are quantified in terms of a "percentage stress" as
compared to typical stress levels (or assumed field conditions). The
test objective is to estimate the
B(1) life for the part (i.e. time at which reliability is
equal to 99%) at the typical operating conditions (i.e.
Stress=100%), in miles.
Review Study...
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Case Study
5:
Using Indicator Variables
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Description
A sample of electronic components are subjected to a
quantitative accelerated life test in which three stress types are
applied to the units. The stress types include temperature, voltage
and a third indicator variable to describe whether the units are
operated continuously or turned on and off. The general log-linear
model is used to analyze the data set for this test.
Review Study...
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Case Study
6:
Stability / Shelf Life Study
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Description
A consumer product (e.g. a mouthwash, shampoo, etc.) is
made up of three main ingredients (ingredients A, B and C), that have
a characteristic (e.g. concentration) that may or may not
change with time. This example looks at data obtained during a 12
month test period to predict the percent out of compliance after 24
months, as well as the behavior of each characteristic over time.
Review Study...
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Case Study
7:
Accelerated Life Test Plans |
Description
A reliability group in a semiconductor company is planning an
accelerated test for an electronic device. This example demonstrates
how to plan such a test using ALTA's Accelerated Life Test Plans
utility.
Review Study...
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Case Study
8:
Multiple
Time-Varying Stresses |
Description
The cumulative damage model allows you to analyze accelerated life
testing data with up to eight time-varying stresses. In this example,
we consider such a case and look at how to create stress profiles in
which stress is a function of time.
Review Study...
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Guest Submission Case Studies
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In addition to the case studies prepared by ReliaSoft personnel, we
welcome contributions from the accelerated life testing community.
To share information about your accelerated life testing and
analysis techniques with your colleagues,
submit your findings for incorporation into our collection of
"Guest Submission Case Studies."
Review Guest
Submission Case Studies...
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Contact the
Webmaster with questions or comments regarding these case studies
or to make a guest submission.
1The case studies are a representative sample
of actual analyses, generalized to remove any association with the
exact product and/or manufacturer. The data, exact test method and/or
stress levels utilized may have been modified in cases where the
actual information was deemed to be confidential.
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Version
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