scholarly journals COMPARATIVE STUDY OF DIFFERENT MAINTENANCE STRATEGIES

Author(s):  
I.V. Tolok ◽  
G.V. Banzak ◽  
E.S. Lenkov ◽  
L.M. Vozikova

A characteristic feature of complex technical objects for special purposes is the presence in their composition of a large number (tens, hundreds of thousands) of various types component parts, which have different levels of reliability, different patterns of their wear and tear processes. This feature requires a more subtle approach to the organization and planning of maintenance in course of their operation. The problem is that in the development of such facilities, all issues related to maintainability and maintenance should be addressed already at the early stages of facility design. If you do not provide in advance the necessary hardware and software for the built-in monitoring of technical condition (TC) of the object, do not develop and "build" the maintenance technology into the object, then it will not be possible to realize in the future a possible gain in the reliability of the object due to maintenance. Since all these issues must be resolved at the stage of object creation (when the object does not yet exist), mathematical models of the maintenance process are needed, with the help of which it would be possible to calculate the possible gain in the level of reliability the facility due to maintenance, to estimate the cost costs required for this. Then, on the basis of such calculations, make a decision on the need for maintenance for this type of objects and, if such a decision is made, develop the structure of the maintenance system, choose the most acceptable maintenance strategy, and determine its optimal parameters. The article shows that the optimal parameters of various maintenance strategies significantly depend on both the reliability and cost structure of the facility and specified requirements for the facility's reliability . The higher the specified value , the more serviced items should be included in the optimal maintenance strategy. It has also been proven that the effectiveness of various maintenance strategies depends significantly on the reliability and cost structure of object. If the distribution of cost restored (including serviced) elements is closely correlated with the distribution of their reliability indicators, difference in effectiveness of different maintenance strategies is reduced. This is clearly seen in the example of Test-2 object, for which the least reliable elements are also the most expensive.

Author(s):  
S.V. Lienkov ◽  
I.V. Tolok ◽  
G.V. Banzak ◽  
R.Yu. Koltsov ◽  
E.S. Lenkov ◽  
...  

A characteristic feature of complex technical objects for special purposes is the presence in their composition of a large number (tens, hundreds of thousands) of different types component parts that have different levels of reliability, different patterns of their wear and tear processes. This feature requires a more subtle approach to the organization and planning maintenance in the course of their operation. The problem is that in the development of such facilities, all issues related to maintainability and maintenance should be addressed already at the early stages of facility design. If you do not provide in advance the necessary hardware and software for the built-in monitoring of the technical condition (TC) of the facility, do not develop and “build” the maintenance technology into facility, then it will not be possible to realize in the future a possible gain in the reliability of the facility due to maintenance. Since all these issues must be resolved at the stage of object creation (when object does not yet exist), mathematical models of the maintenance process are needed, with the help of which it would be possible to calculate the possible gain in the level of reliability facility due to maintenance, estimate the cost costs required for this. Then, based on such calculations, make a decision on the need for maintenance given type of objects and, if such a decision is made, develop the structure of the maintenance system, choose the most acceptable maintenance strategy, and determine its optimal parameters. The paper shows that the model for the regulated maintenance strategy is an improved version of the already known models and is introduced into the complex model for the purpose of comparative assessment of various maintenance strategies. In addition, it should be borne in mind that in practice, some cases, a regulated maintenance strategy may be preferable to MCC strategies.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Alireza Irajpour ◽  
Ali Fallahian-Najafabadi ◽  
Mohammad Ali Mahbod ◽  
Mohammad Karimi

The purpose of this paper is to provide a framework that can identify and evaluate the effectiveness of a given maintenance strategy and to rank components of maintenance system. The framework is developed using DEMATEL method on maintenance strategy as a guideline. To gain a richer understanding of the framework, a questionnaire is constructed and answered by experts. Then the DEMATEL method is applied to analyze the importance of criteria and the casual relations among the criteria are constructed. The scope of the paper is limited to performance measurement of maintenance strategies. It is found that the framework is applicable and useful for the strategic management of the maintenance function. It is observed that the influencing and preferred infrastructures for designing Learning and Training are three components, that is, optimal maintenance, CMMS, and RCM which are interdependent on each other and are the fundamental components to realize the designed goals of maintenance process. This paper provides an overview of research and developments in the measurement of maintenance performance. Many tools and techniques have been developed in other fields. However, the applicability of those tools to maintenance function has never been tried. In that respect this topic is novel. It helps in managing maintenance more effectively.


2011 ◽  
Vol 255-260 ◽  
pp. 3933-3937
Author(s):  
Yu Meng Wu ◽  
Jun Chang

In this paper, decision-making tree and Markov process are used to select maintenance strategies of in-service bridges with the minimum LCC (life-cycle cost). Other costs in life cycle are considered comprehensively when establish the model to find the optimal maintenance strategy. Finally, an example is given to verify the efficiency of the model. The research methodology can provide effective support to bridge maintenance management decision-maker for making management strategies.


Author(s):  
I.V. Tolok ◽  
G.V. Banzak ◽  
E.S. Lenkov ◽  
T.V. Bondarenko

Complex technical objects in modern society are extremely important. Such objects belong to the class of recoverable objects of long-term repeated use. They tend to be expensive and costly to operate. To ensure the required level of reliability during their operation, maintenance is usually carried out, the essence of which is the timely preventive replacement of elements that are in a pre-failure state. A characteristic feature of complex technical objects for special purposes is the presence in their composition of a large number (tens, hundreds of thousands) of different types of component parts that have different levels of reliability, different patterns of their wear and tear processes. This feature requires a more subtle approach to the organization and planning of maintenance during their operation. The problem is that during the development of such facilities, all issues related to maintainability and maintenance should be addressed already at the early stages of facility design. If you do not provide in advance the necessary hardware and software for the built-in monitoring of technical condition (TC) of the object, do not develop and “build” the maintenance technology into the object, then it will not be possible to realize in the future a possible gain in the reliability of object due to maintenance. Since all these issues must be resolved at the stage of object creation (when the object does not yet exist), mathematical models of the maintenance process are needed, with the help of which it would be possible to calculate the possible gain in the level of reliability of facility due to maintenance, to estimate the cost costs required for this. Then, based on such calculations, make a decision on the need for maintenance for this type of objects and, if such a decision is made, develop structure of the maintenance system, choose the most acceptable maintenance strategy, and determine its optimal parameters. In this paper, we study the influence of the coefficient variation on value of the optimal level of maintenance. The work also confirms the general idea that the smaller value of the coefficient variation of random operating time to failure of the serviced elements, greater optimal value of maintenance level should be.


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 3524-3524
Author(s):  
Mohamad Bassam Sonbol ◽  
Luke Mountjoy ◽  
Belal Firwana ◽  
Diana Almader-Douglas ◽  
Kabir Mody ◽  
...  

3524 Background: In mCRC, induction combination chemotherapy with targeted agents is considered the mainstay of treatment. This is typically followed by maintenance therapy vs. observation which had been examined in various trials. However, it remains unclear how best optimize maintenance strategy. We aim to evaluate comparative effectiveness to support best maintenance strategy. Methods: We searched PubMed, Embase, and Cochrane CENTRAL for randomized controlled trials (RCT) evaluating different maintenance strategies in previously untreated mCRC patients (pts): observation (obs), bevacizumab (bev), fluoropyrimidine (FP), FP+bev, or continuing induction regimen (CTX). Outcomes of interest included OS and PFS. The overall effect was pooled using the DerSimonian random effects model. We conducted network meta-analysis based on White’s multivariate meta-regression to pool evidence from direct and indirect comparisons. Agents were ranked using surface under the cumulative ranking (SUCRA) probabilities. Higher SUCRA scores correspond to greater efficacy. Results: Twelve trials at low risk of bias (5540 pts) were included. Network meta-analysis shows no benefit of CTX over obs in terms of PFS (HR 0.7; 95% CI 0.46-1.09) and OS (HR 0.95; 95% CI 0.85-1.07). Compared to obs, maintenance therapy shows PFS benefit (HR 0.58; 95% CI 0.43-0.77) with only a trend in OS (HR 0.91; 95% CI 0.83-1.009). All maintenance strategies (FP, FP+bev, and bev) show significant improvement in PFS over obs. On SUCRA analysis, maintenance treatment (FP or FP+bev) has the highest likelihood of achieving better PFS (67.1% for FP and 99.8% for FP+bev) and OS (81.3% for FP and 73.2% for FP+bev). Conclusions: A maintenance strategy with at least a FP with or without the addition of bevacizumab is preferred. However, given the lack of a clear OS benefit, obs is an acceptable alternative. Optimal maintenance strategies should be dependent on factors including patient preferences, cost and toxicities. [Table: see text]


Author(s):  
Guang Zou ◽  
Kian Banisoleiman ◽  
Arturo González

A challenge in marine and offshore engineering is structural integrity management (SIM) of assets such as ships, offshore structures, mooring systems, etc. Due to harsh marine environments, fatigue cracking and corrosion present persistent threats to structural integrity. SIM for such assets is complicated because of a very large number of rewelded plates and joints, for which condition inspections and maintenance are difficult and expensive tasks. Marine SIM needs to take into account uncertainty in material properties, loading characteristics, fatigue models, detection capacities of inspection methods, etc. Optimising inspection and maintenance strategies under uncertainty is therefore vital for effective SIM and cost reductions. This paper proposes a value of information (VoI) computation and Bayesian decision optimisation (BDO) approach to optimal maintenance planning of typical fatigue-prone structural systems under uncertainty. It is shown that the approach can yield optimal maintenance strategies reliably in various maintenance decision making problems or contexts, which are characterized by different cost ratios. It is also shown that there are decision making contexts where inspection information doesn’t add value, and condition based maintenance (CBM) is not cost-effective. The CBM strategy is optimal only in the decision making contexts where VoI > 0. The proposed approach overcomes the limitation of CBM strategy and highlights the importance of VoI computation (to confirm VoI > 0) before adopting inspections and CBM.


Author(s):  
Mohammad Istiak Hossain ◽  
Jan I. Markendahl

AbstractSmall-scale commercial rollouts of Cellular-IoT (C-IoT) networks have started globally since last year. However, among the plethora of low power wide area network (LPWAN) technologies, the cost-effectiveness of C-IoT is not certain for IoT service providers, small and greenfield operators. Today, there is no known public framework for the feasibility analysis of IoT communication technologies. Hence, this paper first presents a generic framework to assess the cost structure of cellular and non-cellular LPWAN technologies. Then, we applied the framework in eight deployment scenarios to analyze the prospect of LPWAN technologies like Sigfox, LoRaWAN, NB-IoT, LTE-M, and EC-GSM. We consider the inter-technology interference impact on LoRaWAN and Sigfox scalability. Our results validate that a large rollout with a single technology is not cost-efficient. Also, our analysis suggests the rollout possibility of an IoT communication Technology may not be linear to cost-efficiency.


2021 ◽  
pp. 69-79
Author(s):  
V. V. GRITSAN ◽  

The article presents the results of surveys of 311 class IV hydraulic structures carried out in 2016-2020 in the Moscow region. All the reservoirs of the surveyed hydraulic units were classified according to their characteristic features, the technical condition of culverts and dams was assessed, there was established the safety level of both separate structures and hydraulic units as a whole. During the surveys, the technical parameters of the surveyed structures were established, the state of each structure and the hydraulic unit as a whole was assessed, a possibility of their accident and a risk level for the downstream areas were considered. At the same time, recommendations were developed for the elimination of serious damage and, with the help of an examination, the amount of the cost of the necessary repair work was determined. The paper also assesses the issues of the ecological state of the areas where the hydraulic units are located and the hydraulic units themselves as blocks of the ecological framework of the territories.


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