Reliability HotWire: eMagazine for the Reliability Professional
In this issue:

Issue 20, October 2002

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

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Hot Topics  
Determining the Reliability of a System with Load Sharing 
A reliability block diagram (RBD) allows you to graphically represent how the components within a system are reliability-wise connected. In most cases, independence is assumed across the components within the system. Meaning, the failure of component A does not effect the failure of component B. However, if your system consists of multiple components sharing a load then the assumption of independence no longer holds true. If one component fails then the component(s) that are still operating will have to assume the failed unit's load. Therefore, the reliabilities of the surviving unit(s) will change. Calculating the system reliability is no longer an easy proposition. This article will explore the concept of component dependence while using accelerated life test data to determine system reliability.

To read more, see 

Reliability Basics  
The purpose of this section is to offer background and advice to the novice reliability engineer.

Difference Between Physical and Reliability-Wise Arrangement
Reliability block diagrams are created in order to illustrate the way that components are reliability-wise arranged in a system. There are different "structural properties" of a system, such as series, parallel, etc. These structural properties refer to the system's state of success or failure based on the states of its components. However, although the physical structural arrangement is clearly related to the reliability-wise arrangement, the two are not necessarily identical.

To read more, see 

Tool Tips  

The Tool Tips section addresses helpful hints and frequently asked questions about ReliaSoft software products.

  • What are the differences between ALTA 6 Standard and ALTA 6 PRO?

  • Where can I find resources on life data analysis, accelerated life testing analysis and system reliability analysis?

  • How do I specify which time-varying profile(s) to use in calculations when implementing the Cumulative Damage model in ALTA 6 PRO?

To read more, see 

Latest Software Updates
Service Packs for Weibull++ 6 MT (SP3) and MPC (SP2) are currently now available. To determine the compile revision of the application on your computer, select About from the Help menu.


Application Date Created Version
Weibull++ 6 MT 9/13/02 Weibull ++ 6.0.8 - MT 6.1.6
Weibull++ 6 MT Service Pack 9/13/02 SP3 CRV 8 - 6
MPC 3 9/16/02 3.0.6
MPC 3 Service Pack 9/16/02 SP2 CRV 6
Hot News
* Introducing the Ultimate System Visualization and Analysis Tool - ReliaSoft's BlockSim software provides astounding analytical power while maintaining an artful simplicity of use. The new version, BlockSim 6, supports exact reliability computations for the most complex systems, now including configurations with standby redundancy as well as load sharing. The simulation capability for repairable systems analysis is more sophisticated and realistic than ever, now including detailed maintenance parameters, cost summaries, throughput estimations and much, much more. For more information on the features of BlockSim 6, anticipated for release in Winter 2002, please visit
* Introducing Xfmea for All Types of FMEA/FMECA - ReliaSoft's Xfmea software provides expert support for all types of FMEA and FMECA (such as DFMEA, PFMEA, FMECA, etc.) according to the major industry standards and customizable to meet your particular needs. The software facilitates the analysis process and provides flexible data management and extensive reporting capabilities. Xfmea is anticipated for release in Winter 2002 and a sneak preview of the product features is available at
* Reliability Growth Update - ReliaSoft is very pleased to announce that Deere & Company and the U.S. Naval Aviation Depots have signed on as part of the Development Team for the new version of the Reliability Growth software. The new software suite will include the most advanced theoretical models, as developed by Dr. Larry Crow, and will feature his methodology for reliability growth management and planning. Look for more details on this in the months to come!
* Reliability Training Seminars - Upcoming ReliaSoft public reliability training seminars include:


QALT Boot Camp intensive three day course on advanced topics, concepts and applications of quantitative accelerated life testing (QALT) analysis, such as time-varying stress, multiple stress testing and ReliaSoft's ALTA PRO software: November 6 - 8, 2002 in Tucson, Arizona. For more information, see Please remember that registered users of the ALTA PRO software are entitled to attend this seminar at no cost.
- Master the Subject, Master the Tools training seminar for life data analysis, accelerated life data analysis and system reliability analysis: November 18 - 22, 2002 in Tucson, Arizona. For more information, see


Reliability Training Courses at the GM Knowledge Center - We are pleased to announce that once again ReliaSoft will be providing training classes for GM employees and qualified GM suppliers at the General Motors Knowledge Center in Warren, Michigan. The courses offered will cover life data analysis and system reliability, maintainability and availability analysis. For more information, visit the GMU Knowledge Center Web site at or contact ReliaSoft at +1.520.886.0410. Class size is limited. GM suppliers can check with GM for class availability. The remaining 2002 class schedule is as follows:
- October 21 - 23, 2002 - Life Data Analysis
- October 24, 2002 - System Reliability
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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