Author: jhynek

For anyone that has spent a bit of time in reliability the term Weibull distribution has probably come up, or should have come up. It is named after Swedish mathematician Waloddi Weibull, who was the first to describe Weibull in length in 1951. Although Waloddi didn't actually come up with the math for Webiull, the formulas and even an application had been applied years before,  he was the first to describe it and won the honour of having the Weibull distribution named after him.

Weibull Analysis is used to analyse historical failure data and produces failure distributions that we use during a system simulation.

The Weibull Analysis module of Availability Workbench analyses historical failure and repair data by assigning probability distributions which represent the failure or repair characteristics of a given failure mode.

The failure distribution assigned to a given set of times to failure (known as a Weibull set) may be assigned to locations in the RCMCost location hierarchy or failure models in the AvSim module.

The Weibull Analysis Module analyses times-to-failure and time-to-repair data using the following distributions:

Exponential Distribution
1-Parameter Weibull Distribution
2-Parameter Weibull Distribution
3-Parameter Weibull Distribution
Bi-Weibull
Tri-Weibull
Lognormal Distribution
Normal Distribution
Weibayes
Phased Bi-Weibull
Phased Tri-Weibull

I have included a recorded webinar giving a general Webull overview. We of course do not go into detail on the formulas used. If you would like additional information please contact me: jhynek@isograph.com 

Secret might be the wrong word to use here, it could be a matter of just asking myself or technical support the right questions. Even if you’ve been using Reliability Workbench, Availability Workbench, AttackTree+, or Network Availability Prediction for years, you’re probably still finding new features and tips and tricks to help you out in the software. Maybe one day you discovered a time-saver and thought to your self “what else can this software do to make my day easier?”

While there are plenty of helpful features in Isograph’s software to make your day easier, perhaps none is so powerful, incredibly useful, and so under-utilized as Plugins and the DLL. These features allow you to extend the power of Reliability Workbench, Availability Workbench, Attack Tree, and NAP tools to absurd heights. From creating macros for accomplishing tedious tasks, to automating fault tree construction, and even adding new features to the software that we haven’t even thought about, the Plugins and DLL can do it.

As always if you have any questions or need additional information on our products please feel free to contact me

Jeremy Hynek
Isograph, Inc.
jhynek@isograph.com
801 610 0045

Some of you might have noticed we have introduced a new website. This will allow us many advantages over the old site, however, the blog posts have been delayed a bit.

We recently attended the RAMS symposium in Orlando Florida. Where Joe Belland presented his paper on "Diverse CCF in Fault Trees".

SAP can be a great tool for collecting data, however, that data often gets over looked or instances get looked at one by one. Often engineers  wonder what to do with all of that great data collected in SAP? Using the Availability Workbench's certified SAP portal one can import data regarding PM intervals, spares, labour or any other fields that are applicable to the availability, maintenance or reliability of your system.

I have recorded a recent internal meeting regarding the options and benefits offered by Availability Workbench SAP portal.  As always please let me know if you have any questions or need additional information on the portal, jhynek@isograph.com

Isograph is pleased to announce that we have been accepted as a SMRP Approved Provider. If you are not familiar with SMRP (Society of Maintenance and Reliability Professionals), but are interested in maintenance, reliability, availability as well as learning various industry techniques for figuring how to approach your maintenance and reliability. Its worth you time to take a look at this nonprofit professional society.  www.smrp.org .

Going forward, if you attend either our Availability Workbench RCMCost or Availability Workbench Avsim courses you will receive 8 hours per course towards your CMRP continued education.

For additional information on our training courses: TRAINING

For more information on the CMRP certification: CMRP

We have collected commonly asked questions by our 1000's of users. Some of the questions that we'll answer along the way include:
Why do my cut sets show gate names with an asterisk next to them?
OK, so I enter a "failure rate." Is that failures per... hour? Year? Geological epoch? What are the units?
This fault tree takes ages to calculate. Can I speed it up?
Fault tree uses approximation methods for solving the tree? Do I have any control over that?
My computer crashed and I lost 3 hours of work! Can I create automatic backups of my project?
What if I want to see MTTF on my fault tree, instead of Q?
I have a plotter. How do I print the whole tree on one piece of paper?
Can I force scientific notation in the results?
What if I don't want to delete the inputs to a gate when I delete the gate?
I really love the font Comic Sans. Can I use that in my fault tree?
Also, chartreuse is my favorite color. How do I set that as default?
How do I set default options, so I don't have to reset these every time I start a new project?

We'll also look at the useful and often-overlooked Report Options. Did you know that you can force the diagram to be black & white for printouts? Or make the fault tree symbols bigger? Or change the order of the pages?

If you are looking for LOPA information chances are you probably already know what a LOPA is. For any of you are not familiar with a LOPA study, it could mean any number of things. However, for us a LOPA is an acronym meaning: Layer Of Protection Analysis. A LOPA can be a good and logical beginning, or addition, to your PHA (Probabilistic Hazard Analysis) studies. Which leads us to our next acronym ETA (Event Tree Analysis). Event tree analysis diagrams can be an effective approach to tackling your LOPA studies. Since this is probably easier viewed than described please take the time to watch our webinar addressing this topic:

In our webinar series "How to Use Your Tools". We spent about 30 to 40 minutes covering the topic of using Weibull to analyze historical information. This is an educational webinar intended to teach our users and prospective users how to better use our tools to properly model their systems.

Weibull is another treasure to add to your analysis. Weibull analyzes historical failure or repair data and assigns probability distributions which represent the failure or repair characteristics of a given failure mode.
The failure distribution assigned to a given set of times to failure (known as a Weibull set) may be assigned to basic events or generic failure models in the Fault Tree Analysis module and to reliability blocks or generic failure models in the RBD analysis.

The Weibull Analysis Module analyses times-to-failure and time-to-repair data using the following distributions:
• Exponential Distribution
• 1-Parameter Weibull Distribution
• 2-Parameter Weibull Distribution
• 3-Parameter Weibull Distribution
• Weibayes
This webinar is the 6th webinar in this series, topics already covered:

• Fault Tree Analysis
• Fault Tree Analysis and the IEC 61508
• Data Links FMECA to Fault Tree
• Event Tree Analysis as part of a Fault Tree Study
• How to use Markov in an FTA or RBD
• How to use Weibull to analyse historical information

Past webinars can be viewed on our blog www.blog.isograph.com . Its not necessary to have attended past webinar to attend our current webinar. However, for a bit of free training it will be useful to check out the series so far.

We appreciate your support of Isograph. If you have any general questions or comments please feel free to contact me.
Sincerely,

Jeremy Hynek
Isograph, Inc.
Director North American Operations
801 610 0045
jhynek@isograph.com

Given the popularity of our web meeting "building a Fault Tree from a schematic" we have come up with another real world example. This time we will be applying Monte Carlo Simulation to an RBD using our AvSim Software.

Attack trees allow threats against system security to be modelled concisely in a graphical format. The effectiveness of internet security, network security, banking system security, installation and personnel security may all be modelled using attack trees.

In the following webinar we decided to model a threat example in our AttackTree+ software.  We took an article from www.wired.com where hackers remotely killed a Jeep Cherokee while driving 70 miles per hour on the freeway. Using this article we created an example in our AttackTree+ software.

Note: much of the failure rate data was made up using information available on the internet.