Problem Of The Month
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A new problem concerning reliability issues is posted on this web site each month, and a solution is proposed. Use this page to select interesting problems by title.
- June 2001—Flood Data and
Gumbel Largest Distributions updated 6/19/2001
Houston, Texas flood data with prediction of 100 year flood depths at gaging station near downtown using a single maximum flood depth per year - May 2001—Process Reliability
Plots With Flat Line Slopes updated 6/24/2001
A Monte Carlo simulation shows how small effects can destroy predicted output in a production processes - April 2001—Weibull Beta
Slopes For Ball Bearings updated 7/3/2001
What’s the “right” Weibull slope value, beta, to use for ball bearings - March 2001—Heat Exchanger
IRIS Wall Thickness and Gumbel Smallest
Distributions
How to predict end of life from ultrasonic wall thickness inspection data with minimum wall thickness for each tube - February 2001—Spare
Equipment updated 1/26/2001
How and why to add spare equipment - January 2001—Timing of
Maintenance Replacements updated
1/26/2001
Gives replacement concepts and a Monte Carlo simulation is available for no-cost download to illustrate failure intervals - December 2000—Screen Sizes
For Pulverised Materials
WinSMITH Weibull makes a probability plot for sieve data -
- June 1998—Automating Monthly
Weibull Production Plots From Excel Spreadsheets updated 6/19/2001
Batch processing using WinSMITH Weibull cuts time when many plots are required - May 1998—Key Performance
Indicators From Weibull Production Plots updated 6/19/2001
Weibull production Monte Carlo simulation to find how KPI’s relate to demonstrated production output - April 1998—Production
Reliability Example With Nameplate Ratings updated
6/19/2001
How to find reliability losses along with efficiency and utilization losses to quantify the hidden factory - March 1998—Nameplate
Capacity updated 6/19/2001
How to find the nameplate capacity of a production process using Weibull analysis - February 1998—Coefficient of
Variation updated 6/19/2001
Why is the coefficient of variation helpful for process reliability issues and Weibull plots - January 1998—Six Sigma updated 6/19/2001
Six sigma—how is it calculated and used in manufacturing plus preliminary info for Weibull plots -
- December 1997--Waste
Disposal System Failures And Duane AMSAA Plots updated 5/31/98 to correct trend line in Set 5
Duane AMSAA plots used for business decisions and for determining the turnaround period for an actual waste disposal system - November 1997--Total
Productive Maintenance Results updated 1/8/98
with more failure data
Duane AMSAA plots for no-TPM and TPM programs show failures avoided - October 1997--How Much Life
Is Lost From Specific Pump Practices
Losses for each pump practice are quantified - September 1997--Demonstrated
Life Of Pump Components From Pump Practices updated
3/31/98 with more information
Inherent reliability of pump components are derated in a reliability model based on findings of from the pump practices survey - August 1997--Pump Practices
And Component Life Multipliers updated 3/31/98 with more information
Best practices, better practices, and good practices for pump installation and use based on a survey of expert users - July 1997--Monte Carlo
Reliability Model Of A Pressure Vessel
Log-normal plots of random stresses, S-N curves, Miner's rule to failure via Monte Carlo models, pressure vessel wall thickness versus age to failure - June 1997--Pipe Wall
Thickness & Risk Based Inspection
updated 5/31/2001
Weibull plots, characteristic life versus time plots, parameter as function of engineering variables - May 1997--Production
Output/Problems updated 6/19/2001
Weibull plots of production data as a business tool to find the process reliability - April 1997--Tank Bottom
Corrosion
Weibull plots, log-normal plots, normal plots, and likelihood ratio confidence limit plots - March 1997--Remaining Coke
Drum Life updated
5/31/2001
Weibull plots and likelihood ratio confidence limit plots
A few words of caution:
- These problems are not accompanied by complete solutions.
- They do not represent a solution to your problems.
- They are intended to stimulate your interest and comments.
- Use professional judgment in how you apply these items to your problems.
- Sometimes the solutions will be controversial to get your thinking process started.
- Maybe you also have a better idea on how to solve the problem as there are many ways to "skin the cat"--or maybe I've screwed-up the solution (heaven forbid) and you can point out my errors as you check my calculations.
E-mail comments, criticisms, and corrections to: Paul Barringer by
clicking here. Also,
if you have a problem suitable for future listings, submit a problem statement
for consideration. Problems include reliability issues and costs receive
priority.
Technical tools are only interesting toys for engineers until results are converted into money and time for the business. Want to get the interest of your management team? Complete your analysis with a bottom line converted into $'s and time!
