In this issue:

Issue 65, July 2006

*Hot Topics
*Reliability Basics
*Tool Tips
*Latest Software Updates
*Hot News
*Contribute to HotWire

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Hot Topics

Degradation Analysis in Step-Stress Accelerated Testing

Step-stress testing is a very common type of accelerated testing. It is a good way to obtain failures in a relatively short amount of time. There are many variations of step-stress testing. A common type is one in which the units are tested at a given stress level for a certain amount of time. At the end of that time, if there are units surviving, the stress level is increased and held for another amount of time. The data that result from such tests can be analyzed using the cumulative damage model, which computes the degradation (damage accumulated through time and through the increase of stress), in ReliaSoft's ALTA software. Click here for more information about this type of step-stress testing.


Alternatively, there are step-stress tests in which the degradation or performance data that can be directly related to the presumed failure of the product in question are monitored over the duration of the test. This test is essentially a degradation test in time-varying conditions. In this case, the "cumulative damage" (degradation) is measured over time and there is no need to use the complex cumulative damage model to estimate the reliability of the product. This article suggests an approach for using Weibull++ to estimate reliability from degradation data of a product tested using step-stress accelerated testing.

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Reliability Basics

Reliability Growth Test Planning and Management
An effective reliability growth test planning and management strategy can contribute greatly to successful product design and development through its impact on the ability of the design/development team to meet desired reliability goals on time and within the project budget. An effective reliability growth management program both produces and utilizes important information about the reliability of the product design, such as the demonstrated MTBF through testing, the growth in MTBF that has been achieved through implementation of corrective actions, the maximum potential MTBF that can likely be achieved for the product design and estimates regarding latent failure modes that have not yet been uncovered through testing. 

This article presents a brief conceptual overview of a reliability growth test planning/management strategy and data analysis methodology that provide information that can be instrumental to various management decisions for product design/development. Dr. Larry H. Crow, a leading practitioner in the field of Reliability Growth Analysis for over 30 years, developed the approach described in this article and has cooperated with design/development teams in both the military and the private sector to implement, validate and refine the relevant techniques. This article has been written with cooperation from Dr. Crow based on his lectures on the subject and published standards for reliability growth analysis.

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Tool Tips
  • Is there a way to find where a Definition is being used in a RENO project?

  • In BlockSim, how is the sequence of standby units determined?

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Latest Software Updates
New service releases are now available for Xfmea Standard (SR 3.5.3), Xfmea Enterprise (SR 3.5.3) and RCM++ (SR 3.5.3). To determine the compile revision of the application on your computer, select About from the Help menu. More Software Downloads...


Application Date Created Version
Xfmea Standard
Xfmea Enterprise
7/13/06 3.5.3
Xfmea Standard Update
Xfmea Enterprise Update
7/13/06 SR 3.5.3
RCM++ 7/13/06 3.5.3
RCM++ Update 7/13/06 SR 3.5.3
Hot News
* XFRACAS to Be Released Soon   Keep an eye out for our Web-based FRACAS system. XFRACAS (formerly QTMS) supports the entire incident management process, from the initial development stages to complete tracking of fielded serialized units. It includes complete support for all FRACAS/DRACAS activities and a configurable array of problem resolution processes (from 4 to 8 steps) such as 8D problem resolution, Six Sigma DMAIC and others. Please contact us for more information.
* Lambda Predict 2 ReliaSoft's Lambda Predict software has a major version upgrade close to completion. Future enhancements include the latest in Derating Analysis, allowing users to define their own derating requirements or follow published standards such as MIL-STD-975M and others. Significant enhancements have also been made to Lambda Predicts Browse Library function. Searching for specific component types is even more efficient and user-friendly with this new utility. Watch for the Lambda Predict 2 release in the coming weeks on our homepage at
* Six Sigma Partner and Six Sigma Courses Announced ReliaSoft is proud to announce a strategic partnership with North Carolina-based training and consulting firm LodeStar Institute (LSI). LSI has become a leader in Six Sigma, Lean Sigma, business process improvement and quality-reliability practices by converting significant new data-based methodologies into widely accessible, high performance solutions and training. LSI has built a curriculum around the core functionality of ReliaSoft's intuitive software and LSIs proven process improvement methodologies and these courses are available through ReliaSoft.
* 2007 ARS Call for Presentations - The 2007 Applied Reliability Symposium, slated for San Diego, CA on June 20 - 22, 2007, is currently accepting presentation proposals that address the Symposium theme: "Sharing applications, success stories and lessons learned in reliability and maintainability engineering." The deadline for proposal submissions is December 8, 2006. Subjects that will be covered in the 2007 Symposium include, but are not limited to:
  • Warranty reduction
  • Reliability as an investment, not a cost
  • Specifying reliability and reliability metrics
  • Supplier management
  • Data collection, management and analysis
  • Reliability and safety
  • Reliability and market share
  • Reliability testing
  • Software reliability
  • Manufacturing reliability

For more information, please visit the ARS Web site at or e-mail

* View Event Photos and Order Proceedings from ARS 2006 The 2006 International Applied Reliability Symposium was held in Orlando, Florida on June 14 - 16, 2006. Thank you to all who participated! The Proceedings Order Form and the Photo Album are now available at
* 2006 ARS Asia Pacific - The International Applied Reliability Symposium - Asia Pacific will be held in Kuala Lumpur, Malaysia September 13 - 14, 2006. Event sponsor GE Energy will be hosting a 2-day Reliability Awareness Workshop prior to the event September 11-12. Fact sheets and registration can be obtained at:
Public Training Event Calendar
August 2006
August 7 - 8, 2006: RS 401(C) Life Data Analysis (Condensed) in New Delhi, India
August 28 - September 1, 2006: MSMT Foundations in San Diego, California
September 2006
September 13 - 14, 2006: International Applied Reliability Symposium in Kuala Lumpur, Malaysia
September 18 - 20, 2006: RS 522 Advanced System Analysis in Tucson, Arizona
September 18 - 22, 2006: MSMT Foundations in Manchester, UK
September 21 - 22, 2006: RS 470 FMEA/FMECA in Tucson, Arizona
October 2006
October 9 - 10, 2006: RS 401(C) Life Data Analysis (Condensed) in Bangalore, India
October 18 - 20, 2006: RS 525 Probabilistic Event Analysis in Tucson, Arizona
October 23 - 27, 2006: MSMT Foundations in Frankfurt, Germany
Contribute to HotWire
Contributions Welcomed
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.

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