Module 4 Estimation of Reliability Metrics

Lesson M04-01

Text: Section 6  pages 1 – 4

Duration: 30 minutes

Overview of Reliability Estimation & Methods

In this lesson, we introduce the key steps for estimating reliability metrics.  We also take a look at options for estimating the parameters of the chosen time-to-failure distribution.  Two main methods (that most software programs provide) are discussed conceptually (Maximum Likelihood Estimation and Rank Regression).  Recommendations for choosing a method are also provided.

Module 4 Estimation of Reliability Metrics

Lesson M04-00

Text: Sections 6 & 7

Duration: 2 minutes

Introduction to Estimation of Reliability Metrics Module

This module is the core of life data analysis.  We start by providing an overview of the common methods for estimating the distribution parameters (e.g. Maximum Likelihood Estimation) and provide guidance for choosing a method.  Since quantifying uncertainty in our estimates is critical, we review the use of confidence intervals (or bounds) for this purpose.  Applying the concepts introduced previously, we learn how to utilize selected distributions to estimate reliability statistics of interest.  Treatment of censored data and multiple failure modes follow.  We also look at comparing multiple groups with respect to overall reliability performance.  Finally, we briefly look at nonparametric estimation which does not require any distribution assumption.

CRE Live Preparation Course

Session 6 – Functions and Distributions

Embedded recording of the session

Resources & Links

Contact me anytime with questions or concerns.

Fred Schenkelberg
fms@accendoreliability.com
(408) 710-8248 or via Skype (I’m fmsrel or you can find me by my name, I think)
**Please arrange a time for a call or Skype to make sure I’m available and expect your call.

Additional Reading/Listening

A slew of tutorials on distributions

Expectation and Moment Generating Functions

Hazard to Reliability Functions

The Four Functions

How to Calculate Reliability Given 3 Different Distributions

CRE Live Preparation Course

Session 5 – Statistical Concepts

Embedded recording of the session

Resources & Links

Contact me anytime with questions or concerns.

Fred Schenkelberg
fms@accendoreliability.com
(408) 710-8248 or via Skype (I’m fmsrel or you can find me by my name, I think)
**Please arrange a time for a call or Skype to make sure I’m available and expect your call.

Additional Reading/Listening

A list of short tutorials on statistical terms

A list of short tutorials on basic probability concepts

CRE Live Preparation Course

Session 4 – Finishing Risk Management

Embedded recording of the session

Resources & Links

Contact me anytime with questions or concerns.

Fred Schenkelberg
fms@accendoreliability.com
(408) 710-8248 or via Skype (I’m fmsrel or you can find me by my name, I think)
**Please arrange a time for a call or Skype to make sure I’m available and expect your call.

Additional Reading/Listening

A few questions came up around NTSB and I mentioned the US Consumer Product Safety Commission document on creating safer products, titled: Handbook for Manufacturing Safer Consumer Products. This is a quick read and downloads a PDF.

The NTSB.gov site includes a nice About page that sums up what they do. On the NTSB.gov home page they sum up what they do with: Charged with determining the probable cause of transportation accidents and promoting transportation safety, and assisting victims of transportation accidents and their families.

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An entire sequence of articles on Risk Management topic related to the CRE BOK

Basic Description of a Fault Tree Analysis

A Brief Introduction to Fault Tree Analysis

Fault Tree Analysis 8 Step Process

Benefits of Fault Tree Analysis

Carls book on FMEA Effective FMEAs: Achieving Safe, Reliable, and Economical Products and Processes using Failure Mode and Effects Analysis

SOR 484 FMEA: Top Down or Bottom Up (podcast)

A set of FMEA resources and links compiled by Carl on FMEA

Common Cause Failures

Fundamentals of Hazard Analysis (webinar/podcast)

SOR 150 Introduction to Hazards Analysis (podcast)

4 Effective Risk Mitigation Strategies

FEMA’s Shift to Proactive Risk Mitigation

Reliability and Risk Mitigation Actions

Risk Exposure Reduction and Mitigation

Resilience and Enterprise Risk Management

iso-3100-2018-enterprise-risk-management (book by Greg Hutchins)

CRE Live Preparation Course

Session 3 – Finishing Reliability Foundations,
starting Risk Management

Embedded recording of the session

Resources & Links

Contact me anytime with questions or concerns.

Fred Schenkelberg
fms@accendoreliability.com
(408) 710-8248 or via Skype (I’m fmsrel or you can find me by my name, I think)
**Please arrange a time for a call or Skype to make sure I’m available and expect your call.

Additional Reading/Listening

An entire sequence of articles on Risk Management topic related to the CRE BOK

Basic Description of a Fault Tree Analysis

A Brief Introduction to Fault Tree Analysis

Fault Tree Analysis 8 Step Process

Benefits of Fault Tree Analysis

Carls book on FMEA Effective FMEAs: Achieving Safe, Reliable, and Economical Products and Processes using Failure Mode and Effects Analysis

SOR 484 FMEA: Top Down or Bottom Up (podcast)

A set of FMEA resources and links compiled by Carl on FMEA

Common Cause Failures

Fundamentals of Hazard Analysis (webinar/podcast)

SOR 150 Introduction to Hazards Analysis (podcast)

4 Effective Risk Mitigation Strategies

FEMA’s Shift to Proactive Risk Mitigation

Reliability and Risk Mitigation Actions

Risk Exposure Reduction and Mitigation

Resilience and Enterprise Risk Management

iso-3100-2018-enterprise-risk-management (book by Greg Hutchins)

CRE Live Preparation Course

Session 2 – Reliability Foundations

Embedded recording of the session

Resources & Links

Contact me anytime with questions or concerns.

Fred Schenkelberg
fms@accendoreliability.com
(408) 710-8248 or via Skype (I’m fmsrel or you can find me by my name, I think)
**Please arrange a time for a call or Skype to make sure I’m available and expect your call.

Glossary Type Resources

You may download these glossaries for your use. To use them during the exam you will need to print and bind (3-hole punch and in a binder – even in the Primer’s binder).

Please give it a try and let me know what is missing or any comments or thoughts to make these better documents.

Draft Formulas Glossary

Draft Book Terms Glossary

Additional Reading/Listening

You Are a Reliability Leader, Now Make a Difference

An Introduction to the Cause and Effect Diagram

Mind Mapping for Non-Linear Thinking

Basics of Affinity Diagrams

Introduction to the Quality Triangle

The Quality Triangle and Reliability

Determining Customer Reliability Requirements

Using Reliability Goals to Set Requirements

The Connection of Reliability and Customer Expectations

Reliability Goals

Fundamentals of FRACAS (podcast – links to webinar recording)

Root Cause Analysis

The 5 Whys Method of Root Cause Analysis

Fundamentals of Root Cause Analysis (podcast and webinar)

Ideation and Product Development

Reliability in Product and Process Development

2 Versions of Product Life Cycle Phases

Fundamentals of the Cost of Unreliability (podcast and webinar recording)

Fundamentals of Reliability Performance Monitoring (podcast and webinar recording)

Why DMAIC Endures as a Robust Thought Process

What is Design for Six Sigma?

Introduction to the 6 Sigma Design Approach

System Engineering and Reliability

Life Cycle Cost Analysis and Reliability

When the system is the customer – system integration

CRE Live Preparation Course

Session 1 – Logistics & Leadership Foundations

Embedded recording of the session

Resources & Links

Contact me anytime with questions or concerns.

Fred Schenkelberg
fms@accendoreliability.com
(408) 710-8248 or via Skype (I’m fmsrel or you can find me by my name, I think)
**Please arrange a time for a call or Skype to make sure I’m available and expect your call.

ASQ’s CRE related links

CRE Primer from the Quality Council of Indiana

ASQ Certified Reliability Engineer description

ASQ CRE Body of Knowledge

ASQ FAQ on Calculators

There are many reasons to sit for the CRE certification, and whatever the reason, let’s work together so you can successfully achieve this career milestone. It’s a tough test and covers a broad body of knowledge, yet with a little support and hard work you can do it.

Exam Day Preparation Additional References

18 Tips for Taking Standardized Exams

How to Prepare for the CRE Exam

Top 10 CRE Exam Preparation Tips

CRE Exam Preparation

Recipe for CRE Exam Preparation

May Require Library Access

Appelhans, Bradley M., and Ronald R. Schmeck. “Learning styles and approach versus avoidant coping during academic exam preparation.” College Student Journal 36.1 (2002): 157+. Academic OneFile. Web. 8 May 2016. (abstract only)

How to Study and Prepare Additional References

In Outliers: The Story of Success by Malcolm Gladwell he talks about 10,000 hours of deliberate practice to become an expert. It’s the deliberate part that is important. Coaching, guidance, and feedback are essential in order for the practice to be useful in developing mastery.

One scholarly paper discusses the role of deliberate practice. While deliberate practice may not be the only way to achieve mastery, and even with such practice one still may not achieve mastery, the idea that getting feedback is essential.

K. Anders Ericsson, Ralf Th. Cramp, and Clemens Tesch-Romer, “The Role of Deliberate Practice in the Acquisition of Expert Performance.” Psychological Review 1993, Vol. 100. No. 3, 363-406.

Here’s an article that outlines best practice for studying – my favorite is taking a nap after a study session. 15 Smart Study Tactics Based on the Latest Brain Research, by Saga Briggs, informED, May 2nd, 2016.

Additional Reading

Benefits of Reliability Engineering (article)

Good mind (article)

Finding Value (ebook)

Management Role Concerning Safety, Quality, and Reliability (article)

Elements of a Reliability Manual (article)

Role of Reliability in an Organization (article)

Supplier Reliability Program Maturity (article)

SOR 045 Supplier Not Meeting Your Reliability Requirements (podcast)

Ethics and Your Work as a Reliability Engineer (article)

The ASQ Code of Ethics

Reliability Role and Safety and Liability (article)

SOR 042 Reliability and Senior Management (podcast)

Module 3 Assessing & Selecting Models for Time-to-Failure Data

Lesson M03-02

Text: Section 5

Duration: 17 minutes

Next, we illustrate the use of Minitab software for constructing and interpreting probability plots.

Example dataset

Module 3 Assessing & Selecting Models for Time-to-Failure Data

Lesson M03-03

Text: Section 5  pages 5 – 15

Duration: 18 minutes

Now that we are familiar with the purpose and interpretation of probability plots, we dig a bit deeper to understand why and how they actually work.  Through an example, we see that the probability plot is simply a transformed (linearized) cumulative failure probability function that allows us to view significant departures of the data from an assumed model.  We also look at how probability plots may be constructed without the use of statistical software.

Module 3 Assessing & Selecting Models for Time-to-Failure Data

Lesson M03-04

Text: Section 5

Duration: 7 minutes

In this lesson, we simply extend the distribution fitting demonstration in Minitab to include right-censored data.

Module 3 Assessing & Selecting Models for Time-to-Failure Data

Lesson M03-05

Text: Section 5

Participant Guide: Module 3 pages 22 & 23

Duration: 18 minutes

Here, you have an opportunity to practice using Minitab to produce probability plots to a couple of datasets and interpret the results.

Exercises

1. 8 units were tested until failure and the failure times (in cycles) are: 5323, 2133, 16709, 7746, 8782, 14033, 2406, 2699 (Data is also found in Dataset_1.MTW)

a) Use Distribution Fitting to fit Weibull, Lognormal, and Exponential distributions to the data

b) What are your conclusions?

2. 20 switches were put on a rig test. 15 units failed and 5 were right-censored (Data is found in Dataset_2.MTW)

a) Use Distribution Fitting to find plausible distributions that describe the data

b) What are your conclusions?

Here are the two exercise files mentioned:

Dataset_1.MTW
Dataset_2.MTW

Module 3 Assessing & Selecting Models for Time-to-Failure Data

Lesson M03-06

Text: Section 5 pages16 & 17

Duration: 7 minutes

When our dataset includes failures from more than one failure mode, it’s generally useful to select individual models for each failure mode and then combine the results to calculate the overall reliability.  In this lesson, we illustrate the process to fit models by failure mode.  We need to apply the concept of “competing risk” and appropriately right-censor the data at failure times for failure modes other than the one we are fitting the model for.

Module 3 Assessing & Selecting Models for Time-to-Failure Data

Lesson M03-07

Text: Section 5

Duration: 17 minutes

Following the exercise related to multiple failure modes, we discuss some other considerations for selecting distributions.

Exercises

15 independent pumps have been utilized in a water treatment facility. 3 pumps have not failed. The failure data is found in Dataset_3.MTW.

1. Fit distributions to each failure mode and select a model that best describes each failure mode.

Here is the exercise file mentioned:

Dataset_3.MTW