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******* This page is under development and will during the spring and summer of 2014 be subject to many changes.****

TPK 5170 RAMS Assessment and Optimization

Brief background of course

This course is the specialization course in reliability, availability, maintenance and safety (RAMS) in the last fall semester of the (2 year) international master program in RAMS and the (5 year) master program in Mechanical Engineering (in Norwegian: Produktdesign og Produksjon - PUP). The course introduces some new methods, and makes a more thorough presentation of methods introduced in previous RAMS-related courses.

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  • Lecturer:

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  • Mary Ann Lundteigen
  • The first lecture will be held on Tuesday August 19th 8:15-11:00  in VG13
  • Course description is found here
  • General information about the course (motivation, learning objectives, and related information) is found here
  • The lecture plan for the entire semester is found here
  • The time table is found here
  • Textbook and course material are from:

The course belongs to the large envelope of RAMS courses given from the department of Production and Quality Engineering at NTNU.  The course is adminstred by the RAMS group at this department. It is expected that the students already have taken (or have relevant background corresponding to):

  • TPK 4120: Safety and Reliability
  • TPK 4140: Maintenance Management 
  • TPK 5160: Risk Analysis 

This course replaces the earlier arrangement with two specialization modules in RAMS, one in risk and reliability and one in maintenance optimization (each with 3.75 credit points). This means that TPK 5170 includes some subjects from both areas: risik and reliability and maintenance optimization, and gives 7.5 credits (i.e., as a regular course normally does at NTNU).

  • You may ask why this is necessary, if the you (for example) are focusing mainly on risk analysis in the specialization project and master thesis. The answer from our This course should give you the remaining topics that we - as a RAMS group - think you should have when you leave NTNU with a specialization in RAMS.

The responsible person for TPK 5170 in the fall of 2014 is Professor Mary Ann Lundteigen. She will give approximately 60% of the lectures. Since this is a specialization course, some "specialists" are brought in for specific topics. For example, Associate Professor Yiliu Liu  will lecture methods like PetriNets. Lectures that belong to the topic maintenance optimization are planned to be lectures by Professor Jørn Vatn our new Professor Anne Barros.

It may be remarked that this course may, from the fall of 2015, change the name to "Asset management methods". A new course in "Reliability of safety-critical systems" ("SIS course") will at the same time be introduced (from spring 2015). Topics related to  reliability assessment will be transferred to the new ("SIS") course, and it is planned that TPK 5170 with its new profile will expand on topics related to maintenance optimization and the estimation of remaining useful life. The changes will be available http://www.ntnu.edu/studies/courses, once implemented.

Course objective and motivation

The main objective of this course is to increase the depth of understanding about RAMS assessment and optimization models and methods. Such models and methods may be useful for several purposes, including:

  • Definition of requirements (how reliable must a system be?)
  • Implementation of requirements (how should we design the system in order to meet stated reliability?)
  • How may we operate the system in order to minimize costs and time?
  • How may it be required to operate the system to be sufficiently safe?
  • How can we support our models and methods with data, and can these data be determined?

As already mentioned, the course aims to study already lectured methods and models in more detail, to add more perspectives to the understanding. Some new models methods are also introduced so that the students, after having taken the course, will have a solid toolbox of models and methods to use in their future work career.  

Expected learning outcome

Knowledge:
Obtain a more thorough understanding of the theoretical foundation and the practical applications of RAMS assessment and optimization methods. 

Skills:
Being able to identify suitable frameworks, methods, and software and to use these to solve RAMS assessment and optimization tasks.

General competence:
Understand RAMS as an important cornerstone of industrial and commercial systems and in the public administration. 

 

Industry relevance

Reliability assessments of safety-critical systems are key services provided by many consultancy companies, such as with Safetec, Lloyd's Register Consulting, and DNV-GL (link to the GL-part of the services), and Lilleaker Consulting. Manufacturers like ABB, Siemens, AkerSolutions, FMC, Kongsberg Maritime and many others need to design systems in light of reliability requirements, and also demonstrate (sometimes with assistance of the consultancy companies) that the reliability requirements are met. End users, like railway service providers like Jernbaneverket, oil companies like Statoil, Det Norske, GDF-Suez, Shell and Conoco-Phillips, and Wintershall, and other industries like smelting plants and water power suppliers must be competent to select proper system design, follow up the system performance and select the most suitable maintenance strategies to keep costs and safety within the accepetable limits.

Topics covered

With the prevailing profile of the course, there are two main subject areas of this course: (info) Reliability assessment methods with focus on the application with safety-critical systems, and (info)(info) Maintenance optimization models and methods which have a broader application area.

 

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Reliability assessment of safety-critical systems       

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  • Information about tutorials and exercises is found here
  • Exam: 
    • There will be a written exam. It is not allowed to bring any other material to this exam than a calculator and a table of formula (the latter is prepared during the semester by the lecturer)
    • More information about the exam is found here

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Lectured topic

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Development of reliability requirements

 

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SIL allocation

LOPA

Risk graph

Minimum SIL

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 PDS method

PetriNet

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Architectural constraints: According to standards like IEC 61508, it is not sufficient to demonstrate that a SIL requirement has been met by showing that the average PFD or PFH is sufficiently low and within the specified range of the SIL  requirement. A SIL requirement also poses some restrictions on how a safety-critical function can be designed, in terms of architecture. These requirements are sometimes referred to as architectural constraints.

Partial testing: For some type of components, like valves, it has been more common to also do partial stroke testing in addition to full functional testing. The reason for introdocing this testing strategy may be to improve safety, or to maintain safety while extending the intervall of full function testing. Analytical models have been suggested for this purpose, and we will review these.

Imperfect testing: Many of the methods used to calculate the average PFD assumes that the functional tests are perfect, meaning that all dangerous undetected (DU) falures are revealed by the test. This is not always the case, and the effect of not taking this "imperfectness" into account will be that the average PFD is underestimated. The way this situation is treated overlaps to some extent with how partial testing is modeled.

SIL follow-up in operation: It is important to maintain the reliability performance throughout the whole operational life of a safety-critical system. This may explained by using a car as an example. You may buy a car with a certain designed-in performance, including reliability, based on the engine type, safety features, type of chassis, and so on. Still, the experienced performance of the same type of car may be different for different drivers. If we exclude fabrication errors, the performance of the car is influenced by the driver's driving habits, amount of driving, environment (icy, cold, hot,..), age and so on.

 

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Architectural constraints

 

Partial stroke testing

 

Imperfect testing

 

SIL follow-up

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Maintenance optimization and management (1)

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Age, block and minimal repair strategies.

(2 lectures - Jørn V, Anne)

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The intervals of maintenance for safety-critical systems are normally determined from the reliability analyses. For other systems, we may use decide upon intervals of testing using different maintenance strategies established by the RCM decision logic. These models include parameters like costs, failure rates, and aging. The models come of with the answer to the following two questions: When should we do maintenance and what tasks and equipment should be included. The application of these methods are many. Two examples are maintenance planning of railway tracks and another is planning of intervention (for maintenance purposes) of subsea equipment. Sub-topics also covered under the same "umbrella" are:

 

  • Modeling of effective failure rate: Maintenance interval and and intervention level (extensiveness of maintenance) is obviously influencing the failure rate of the components. This topic concerns the modeling of the relationship between these two parameters and what we can refer to as the effective (or resulting) failure rate.
  • Weibull renewal: **Say something here** 
  • PF models and state based models: **Say something here** 

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Spare part optimization:

(1 lecture - Yiliu)

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Tutorials & Project

There will be mandatory problems/tasks to solve as part of the course.

TopicProblems Software
Reliability assessmentProblems will be selected from the following booklet Matlab, Maple, Grif
Maintenance optimization Problems will be .... Excel

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