Product Reliability and Availability in Field Data

An Object-Oriented Modelling Framework for Probabilistic Risk and Performance Assessment of Complex Systems

Penttinen J-P, Ramentor Oy

Doctoral dissertation
4 September, 2020

"This thesis introduces a modelling framework, which is developed for risk and performance assessment of large and complex systems with dynamic behaviours. The framework supports the most common reliability and operation modelling techniques, and permits their customisation. This ensures a high degree of freedom for the modeller to describe accurately the system without limitations imposed by an individual technique. The use of an object-oriented paradigm increases flexibility and decreases the semantics gap between the model and real world, which are issues with traditional techniques. The framework is named as Analysis of Things (AoT) to emphasise its universal nature and wide application possibilities. The AoT models are defined by using a Triplets data format, which is platform-independent and tabular. A single table declares the applied modelling techniques, creates the model structure, and assigns the parameter values. The format enables straightforward manual model edit while maintaining direct database compatibility. This thesis also documents a calculation engine, which has been developed for analysis of AoT models. The engine compiles dynamically the most efficient simulation algorithm for each modelling technique. A catalogue of built-in techniques is included in this thesis to demonstrate the application of the framework. The configuration of the simulation algorithm is presented for each technique. The AoT model creation is illustrated by using simple example models. Various techniques can be combined to build a comprehensive risk and performance model that systematically includes all essential details. The advanced features of the AoT framework have wide-ranging applications for analysis of reliability, availability, and operational performance of complex industrial products and processes."


Modeling Future Hadron Colliders’ Availability for Physics

Niemi A, CERN

Doctoral dissertation
17 April, 2019

"This thesis presents an availability model for the Future Circular hadron Collider. The thesis validates the model against LHC operations and shows preliminary results on the FCC availability and luminosity production. Ramentor’s ELMAS software was chosen as the platform for the model. ELMAS is designed as a fault tree software. However, the developed model combines fault trees with Markov models. This feature was implemented by adding custom Java code and libraries to models. This reliance on a custom code was not the ideal solution and lead to the development of the OpenMARS approach. This approach allows combining the most common risk assessment and operation modeling techniques and connecting the models made with these techniques. This thesis presents the basic concept of this approach and shows how the collider operations model can bei mplemented with it. The discussion section also provides ideas on how the study would have proceeded if the collaboration with Ramentor Oy had not been an option and further applications of the OpenMARS approach."


An open modelling approach for availability and reliability of systems

Penttinen J-P, Ramentor Oy
Niemi A, Gutleber J, CERN
Koskinen K, Coatanea E, Laitinen J, Tampere University of Technology

Reliability Engineering & System Safety, Volume 183, March 2019, Pages 387-399
26 November, 2018

"This paper introduces an Open Modelling approach for Availability and Reliability of Systems (OpenMARS), which is developed for risk and performance assessment of large and complex systems with dynamic behaviours. The approach allows for combining the most common risk assessment and operation modelling techniques. This ensures a high degree of freedom for the modeller to accurately describe the system without limitations imposed by an individual technique. OpenMARS uses a platform-independent tabular format to define the used modelling technique, to create the model structure, and to assign the parameter values. We developed the format to enable a straightforward manual model definition while maintaining database compatibility. This paper also presents our calculation engine for stochastic simulation-based analysis of OpenMARS models. Our intention is to use this approach as a basis for new software. We demonstrate the feasibility of OpenMARS with an example of a multi-state production process that is subject to failures. The example creates a comprehensive system model by combining interconnected failure logic, operation phase, and production function models. We believe that the advanced features of OpenMARS have wide ranging applications for analysis of reliability, performance, and energy efficiency of complex industrial processes."

Preprint in CERN Document Server:
Specification in CERN Document Server:

Availability Modeling Approach for Future Circular Colliders Based on the LHC Operation Experience

Niemi A, Apollonio A, Gutleber J, Sollander P, CERN Penttinen J-P, Ramentor Oy Virtanen S, Tampere University of Technology

Physical Review Accelerators and Beams 19, 121003 27 December, 2016

"Reaching the challenging integrated luminosity production goals of a future circular hadron collider (FCC-hh) and high luminosity LHC (HL-LHC) requires a thorough understanding of today’s most powerful high energy physics research infrastructure, the LHC accelerator complex at CERN. This paper introduces the FCC reliability and availability study, which takes a fresh new look at assessing and modeling reliability and availability of particle accelerator infrastructures. ELMAS version 4.8, used for this study, permits specifying production functions, semi-Markov chain transition logic and conditional operation schedule specifications with user-specific Java snippets."


Advanced Fault Tree Analysis for Improved Quality and Risk Assessment

Penttinen J-P, Lehtinen T, Ramentor Oy

10th World Congress on Engineering Asset Management (WCEAM 2015) 26 March, 2016

"Traditional fault tree analysis (FTA) has formed a common language for the modelling and analysis of risks of complex systems. The approach can be used for a large variety of cases, and several tools exists for the method. Advanced FTA is needed to apply the FTA approach also for dynamic systems with time dependent activities. The traditional FTA is extended by including for example modelling and simulation of operation or phase changes of the systems, stochasticity and delays of relations, and maintenance actions for the components. The rules between the failures and other simulated properties are defined by including Java-based scripts to the model. This allows a great freedom to model any type of dynamic situations. A tool named ELMAS has been created to make the use of the advanced FTA approach as straightforward as possible. It allows to model the static and simple relations by using the traditional FTA method. Complex and dynamic relations are included by using modules that can be freely defined based on the needs of the case."


Advanced RCM Industry Case - Modeling and Advanced Analytics (ELMAS) for Improved Availability and Cost-efficiency

Tammi M, Vuorela V, Lehtinen T, Ramentor Oy

10th World Congress on Engineering Asset Management (WCEAM 2015) 26 March, 2016

"Today there are several well-proven analysis methods available for reliability and maintenance management. Most of them are however developed for analyzing safety-critical applications. Within basic industry the focus is typically on cost management and traditional analysis methods are often presumed as too laborious. This seminar paper is based on an ELMAS reliability analysis per-formed for a production-critical molding crane in metals industry at SSAB Raahe factory in Finland. The main objective was to identify risks and optimize maintenance actions in a cost-effective manner. Another objective was to develop a systematic procedure for managing cost risks of production-critical process parts. The analysis combines the main benefits of fault tree analysis (FTA), failure mode and effect analysis (FMEA) and reliability centered maintenance (RCM) to form a systematic method for performing versatile analysis and corrective action planning."


Spare Part Stock Modeling and Cost Optimization

Turpela J, Lehtinen T, Ramentor Oy

10th World Congress on Engineering Asset Management (WCEAM 2015) 26 March, 2016

"Modeling and planning the spare part item stock is a quite complex, but utmost rewarding task regarding the operational excellence of a manufacturing industry company. The challenge with the design is derived from multi-variable optimization tasks, including e.g. consumption rate of an item, division of stocking costs, and potential shortage costs. This applies especially in case of new spare part item with no history data for defining the consumption rate."


Application of Design Review to Probabilistic Risk Assessment in a Large Investment Project

Virtanen S, Tampere University of Technology Penttinen J-P, Ramentor Oy Kiiski, M, Jokinen J, Pöyry Finland Oy Probabilistic Safety Assessment and Management PSAM 12 22-27 June, 2014 "In this paper, we present a systematic and comprehensive Design Review (DR) process that is integrated in design and engineering stages of final disposal facilities of spent nuclear fuel. The review process consists of seventeen interconnected phases and in the paper the methodology of certain phases is described in more detail." URL:

Integrated Business and Technical Product Reliability Design

Virtanen S, Tampere University of Technology

Seminar of BRED-project (Association of research and development of electronics KOTEL ry) 31 December, 2008

"The traditional and still dominating method for product design is focused on optimising the technical performance of a product. The reason for this is simple, there is no easily available and comprehensive design method or tool to integrate the reliability and maintainability (R&M) considerations and effects in product design. As more the companies’ management have experienced the meaning of Product’s R&M as competitive factors in their business, as more they have started to invest R&M engineering and development. This was also a starting point from where this project was launched."

Download the publication: Project Report KOTEL 256

Product Reliability and Availability in Field Data

Nevavuori L, Service Development, KONE Corporation

Proceedings of the 3rd World Congress on Engineering Asset Management and Intelligent Maintenance Systems (WCEAM-IMS) 27-30 October, 2008

"Demands for the dependability have risen in the elevator industry during the recent years. The aim of the paper is to introduce a case study that was performed by KONE’s reliability and maintenance departments in the beginning of year 2007. The case is about products’ perceived dependability follow-up. Moreover, a target is to present how reliability data was collected as well as utilized in reliability centered maintenance planning. In this case the starting point for a dependability follow-up was the back reported field data from maintenance actions."

Download the publication: Product Reliability And Availability in Field Data