Showing papers on "Preventive maintenance published in 2014"

Two-stage hybrid flow shop scheduling with preventive maintenance using multi-objective tabu search method

Abstract: This paper investigates an integrated bi-objective optimisation problem with non-resumable jobs for production scheduling and preventive maintenance in a two-stage hybrid flow shop with one machine on the first stage and m identical parallel machines on the second stage. Sequence-dependent set-up times and preventive maintenance (PM) on the first stage machine are considered. The scheduling objectives are to minimise the unavailability of the first stage machine and to minimise the makespan simultaneously. To solve this integrated problem, three decisions have to be made: determine the processing sequence of jobs on the first stage machine, determine whether or not to perform PM activity just after each job, and specify the processing machine of each job on the second stage. Due to the complexity of the problem, a multi-objective tabu search (MOTS) method is adapted with the implementation details. The method generates non-dominated solutions with several parallel tabu lists and Pareto dominance concept. ...

Opportunistic maintenance (OM) as a new advancement in maintenance approaches: A review

Abstract: Purpose – This paper reviews the literature on opportunistic maintenance (OM) as new advance maintenance approach and policy. The purpose of this paper is to conceptually identify common principle and thereby provide absolute definition, concept and characteristics of this policy. Design/methodology/approach – A conceptual analysis was conducted on various literatures to clarify a number of principle and concepts as a method for understanding information on OM. The analysis involves the process of separating the compound terms used in the literatures into a few parts, analyse them and then recombining them to have more clear understanding of the policy. Findings – The paper discussed the maintenance approach, genealogy, principle, concept and applications of OM both in numerical analysis and real industry. OM policy is developed based on combination of age replacement policy and block replacement policy and in practical; OM is applied as the combination of corrective maintenance which is applied when any ...

On the Use of Mean Residual Life as a Condition Index for Condition-Based Maintenance Decision-Making

Abstract: This paper provides a methodology to analyze the efficiency of mean residual life in condition-based maintenance decision-making. A degradation-threshold-dependent-shock model is used to describe the evolution of a system subject to the dependent and competing failure modes due to degradation and shock. Based on this model, we compute the mean residual life of system and analyze its monotonicity. This property of mean residual life function allows introducing a new condition-based maintenance strategy whose preventive maintenance decision is based on the mean residual life. The proposed strategy is then compared to a maintenance strategy based on the degradation level only. Analyzing the equivalence, the performance and the flexibility of both strategies allow us to give some conclusions on the interest of the mean residual life as a condition index for maintenance decision-making.

Arc detection in pantograph-catenary systems by the use of support vector machines-based classification

Abstract: Predictive Maintenance, Prognostics and Reliability Centered Maintenance approach are becoming more and more important in the railway sector to reduce costs of operation and to increase reliability and safety. In fact, these are fundamental to optimize the maintenance process, to define new measures and algorithms which locate faults, to monitor health conditions of subsystems and to estimate residual life of components. In some cases it's possible to use existing sensors and existing processing hardware to extract new information from the existing available data. It's clear that this is usually the best option because the benefit can be achieved with little or no cost at all. This paper describes the result of a study performed with the aim of detecting arcing events without the need of additional equipment mounted on board the train. A set of data relative to voltage and current collected on high speed trains along with a set of measurements coming from photosensors are available. The data are processed by the use of an advanced classification technique, Support Vector Machines, with the aim of extracting important information such as the time coordinate related to anomalies in the overhead contact line and the status of the pantograph contact strip.

A Generalized Result for Degradation Model-Based Reliability Estimation

Abstract: Reliability estimation based on degradation model is a feasible and low-cost alternative used to estimate reliability for highly reliable systems when the failure-time data are rare. Based on reliability estimation by degradation modeling, preventive maintenance work orders need to be timely triggered to minimize unscheduled downtime. In Trans. Autom. Sci. Eng., vol. 9, no. 1, pp. 209-212, Jan. 2012, Sun et al., an approach to dynamically extract maintenance threshold is presented for maintenance scheduling, in which the reliability threshold for maintenance is determined by maximizing the expected availability and the reliability estimation is achieved by a modified two-stage degradation modeling approach. Although this approach is novel and useful, its reliability estimation is an asymptotic solution in long time scale. In this paper, we generalize the above result by considering a general degradation path model and provide the exact and explicit formulation for reliability estimation. Additionally, a maximum-likelihood estimation method for parameters in the presented model is proposed based on the historical degradation observations. Finally, an example is provided for illustration.

Optimization of Life-Cycle Maintenance of Deteriorating Bridges with Respect to Expected Annual System Failure Rate and Expected Cumulative Cost

Abstract: Civil infrastructure systems are subjected to progressive deterioration resulting from multiple mechanical and environmental stressors. This deterioration process is developed under uncertainties related to load effects, structural resistance, and inspection outcomes, among others. In this context, life-cycle optimization techniques provide a rational approach to manage these systems considering uncertainties and several budgetary and safety constraints. This paper proposes a novel optimization procedure for life-cycle inspection and maintenance planning of aging structures. In this procedure, the structural system effects are accounted for by modeling the structure as a series, parallel, or a series-parallel system whose components are subjected to time-dependent deterioration phenomena. Different possible repair options are considered depending on the damage state and the outcomes of each inspection. For each component, essential or preventive maintenance aiming at reducing the system failure ra...

Overhead Line Preventive Maintenance Strategy Based on Condition Monitoring and System Reliability Assessment

Abstract: This paper presents a maintenance strategy for overhead lines based on condition monitoring and system reliability assessment. A quantitative relationship between the condition monitoring data and failure rate of overhead lines is established. The system reliability is evaluated using monitoring data; the reliability benefit due to the maintenance of each line is quantified; and the maintenance ranking order is created using the benefit/cost ratio index. The proposed strategy can provide the largest reliability improvement at the lowest maintenance cost and within budget. Case studies were performed on a 182-bus, 5474-MW transmission system located in southwest China.

Condition-based maintenance for multi-component systems using importance measure and predictive information

Abstract: This paper presents a predictive condition-based maintenance strategy for multi-component systems whose structure may impact components deterioration process. To select components for preventive maintenance actions, a decision rule relying on both structural importance measure of components and their predictive reliability that can be estimated at inspection times is proposed. For corrective maintenance actions, an adaptive opportunistic maintenance decision rule taking into account both the criticality level of components and logistic support constraints is introduced. Moreover, both economic and structure dependencies between components are studied and integrated in maintenance model. A 12-component system is finally introduced to illustrate the use and the performance of the proposed predictive maintenance strategy. Indeed, the proposed strategy provides more flexibility in maintenance decision-making, hence leading to significant profits in terms of maintenance cost when compared to existing strategies.

Integrating production planning and maintenance: an iterative method

Abstract: Purpose – Making decisions on production and maintenance separately, as is often done in practice and research literature, may not result in overall optimization. This paper aims to propose a joint method that better integrates production planning and maintenance at the tactical level. The potential of improving the performance of the classic planning method is also explored. Design/methodology/approach – An integrated production planning and maintenance model is proposed. The production capacity losses resulted from both preventive and corrective maintenance activities are considered. Meanwhile, the reliability deterioration of the machine is considered to be operation dependent. An iterative approach is presented to find a solution for the nonlinear model through iteratively solving a sequence of mixed integer linear programming instances, accompanied by modification of some parameters prior to each iteration. Computational experiments are conducted to evaluate the performance of the proposed method com...

Railway condition-based maintenance model with stochastic deterioration

Abstract: The application of mathematical programming for scheduling preventive maintenance in railways is relatively new. This paper presents a stochastic mathematical model designed to optimize and to predict tamping operations in ballasted tracks as preventive condition-based maintenance. The model is formulated as a mixed 0–1 nonlinear program that considers real technical aspects as constraints: the reduction of the geometrical track quality over time is characterized by the deterioration rate of the standard deviation of the longitudinal level; the track layout; the dependency of the track recovery on its quality at the moment of the maintenance operation; the limits for preventive maintenance that depend on the maximum permissible train speed. In the model application, a railway stretch with 51.2 km of length is analysed for a time period of five years. The deterioration model is stochastic and represents the reduction of the standard deviation of the longitudinal level over time. The deterioration r...

Preventive Maintenance of a Multi-State Device Subject to Internal Failure and Damage Due to External Shocks

Abstract: Preventive maintenance is of interest in reliability studies, to improve the performance of a system, and to optimise profits. In this study, we model a device subject to internal failures and external shocks, and examine the influence of preventive maintenance. The internal failures can be repairable or non-repairable. External shocks produce cumulative damage until non-repairable failure occurs. The device is inspected at random times. When an inspection takes place, the level of internal degradation and the damage produced by external shocks are observed. If damage is major, the unit is assigned to preventive maintenance according to the degradation level observed. Minimal preventive maintenance is also undertaken: if internal and external degradation is observed, and only one of them is major, then the device is assigned to preventive maintenance only for the major damage, and the minor damage state is saved in memory. We model the system, solve for the stationary distribution, create measures of reliability, in transient and stationary regimes, and introduce rewards by considering profits and different costs. We show the results in algorithmic form, and they are implemented computationally with Matlab. The versatility of the model is shown by a numerical example.

Integrated maintenance and production planning with energy consumption and minimal repair

Abstract: In this study, we analyze an integrated production-preventive maintenance planning problem where product processing times are affected by machine degradation. Preventive maintenance and repair can return the degraded machines/equipment to normal conditions, which can improve the job processing times and the amount of energy consumed. We propose a mathematical model for an integrated production and preventive maintenance planning problem in a multi-product, multi-period, single-machine manufacturing environment with minimal repair and energy consumption considerations in order to minimize the overall cost of production, inventory, energy, maintenance, and repair. The model investigates the impact of imperfect and “as-good-as-new” (AGAN) maintenance strategies on production plan and total cost. Experimental analyses provide insights about the proposed model: when the sensitivity of processing times to machine health status increases, the required number of maintenance actions increases. In addition, enforcing more number of maintenance actions into a production plan decreases energy cost of the system.

Burn-in and maintenance policies

Abstract: Burn-in is a widely used method to improve quality of products after they have been produced. For a repairable component there are two common types of repair, complete repair and minimal repair. Preventive maintenance policies such as age replacement and block replacement are often employed in field operation. The present paper takes burn-in, maintenance and repair into consideration at the same time and considers related cost structures. The properties of the corresponding optimal burn-in times and optimal maintenance policies are discussed. BATHTUB-SHAPED FAILURE RATE; COMPLETE REPAIR; MINIMAL REPAIR; AGE

Modelling maintenance effects on manufacturing equipment performance: results from simulation analysis

Abstract: Equipment maintenance and system reliability are important factors affecting the organisation’s ability to provide quality and timely services to customer. While maintenance remains an important function to manufacturing, it is only recently that attempts have been made to quantify its impact on equipment performance. In this research, an approach of linking maintenance with equipment performance is developed using simulation modelling. The modelling approach involves defining probabilistic models and assumptions affecting system performance, such as: the probabilistic model for the initial failure rate/intensity of the equipment; the probabilistic model for the system deterioration and corresponding effect; the probabilistic model for the random times of corrective maintenance (CM) and preventive maintenance (PM) that takes into the account the types of maintenance plans/policies and the potential dependency between CM and PM times; and the probabilistic model for the random effects of CM and PM on the r...

Verification of effectiveness of chip seal as a pavement preventive maintenance treatment using LTPP data

Abstract: It is hypothesised that maintenance treatments should be applied in the preventive mode before pavements display significant amounts of distress in order to be more cost-effective. The objective of this study was to verify the concept of preventive maintenance by examining the long-term effectiveness of chip seal treatment in four climatic zones in the USA using the long-term pavement performance database. Pavement sections were categorised into smooth, medium and rough pavements, based upon initial condition (IC) as indicated by the international roughness index. Pavement performance of treated and untreated sections was collectively modelled using exponential regression analysis. Effectiveness was evaluated in terms of life extension, relative benefit and benefit–cost ratio. The results showed that preventive maintenance is cost-effective. The life extension, relative benefit and benefit cost ratio were highest for sections whose IC was smooth at the time of treatment. Chip seal treatment effectiveness ...

On the influence of maintenance activity types on the issue resolution time

Abstract: The ISO/IEC 14764 standard specifies four types of software maintenance activities spanning the different motivations that software engineers have while performing changes to an existing software system. Undoubtedly, this classification has helped in organizing the workflow within software projects, however for planning purposes the relative time differences for the respective tasks remains largely unexplored.In this empirical study, we investigate the influence of the maintenance type on issue resolution time. From GitHub's issue repository, we analyze more than 14000 issue reports taken from 34 open source projects and classify them as corrective, adaptive, perfective or preventive maintenance. Based on this data, we show that the issue resolution time depends on the maintenance type. Moreover, we propose a statistical model to describe the distribution of the issue resolution time for each type of maintenance activity. Finally, we demonstrate the usefulness of this model for scheduling the maintenance workload.

Optimal Production and Maintenance Planning of Biopharmaceutical Manufacturing under Performance Decay

Abstract: Considering the performance decay of the chromatography resins in the downstream purification of biopharmaceutical manufacturing, the maintenance decisions should be made at appropriate times to achieve a good performance of the whole manufacturing process. In this paper, on the basis of the literature work on production planning, a mixed integer linear programming optimization model is developed to address the production and maintenance planning of biopharmaceutical manufacturing under performance decay, in which the total operating profit is maximized. The batch production profiles are tracked by binary variables introduced in the proposed model. The proposed model is then applied to two literature-based illustrative examples. Two scenarios are investigated and compared with the optimal solutions. A discussion about the effects of the maintenance duration and cost and the resin’s lifetime is also presented.

Why and when must the preventive maintenance be performed

Abstract: In this work we will illustrate the criteria useful to identify simple and quick operations through which “the why and the when” a scheduled maintenance can be performed in order to avoid excessive checks and controls, often difficult and expensive to run. The question that in fact arises in the preparation of preventive maintenance program is if it is possible to satisfy the reliability requirements compatible with the economic and safety needs of the user. The answers can only be given following a correct heuristic method. Experimental data, resulting from repetitive measurements, should only serve to build simulation models that can predict what the future will hold and then as subsequent control measurements to confirm the above-mentioned model. This is particularly useful in the planned maintenance schedule, in which you get to answer the question: "how often"? Fit mathematical models allow to calculate, with precision and accuracy, the convenient time at which to intervene. To do this, it is therefore necessary to understand the mechanisms that dominate the evolution of the processes (prognostics) that may lead to failures. We present two examples of applications: one concerning a railway structure and the other relative to an aircraft structure.

Single-machine group scheduling problem considering learning, forgetting effects and preventive maintenance

Abstract: An integrated single-machine group scheduling model is proposed, which incorporates both learning and forgetting effects and preventive maintenance (PM) planning. The objective is to minimise the expected makespan by optimising job sequence and PM decisions. This model contains sequence-dependent set-up time, actual processing time, planned PM time and expected minimal repair time simultaneously. Based on the properties of group production, three learning functions under different circumstances are proposed to deduce the variable processing time of each part, considering the learning effect when consecutively producing identical or similar parts, together with the forgetting effect when transferring jobs interrupts the production process and makes retrogress in learning. Both run-based maintenance and minimal repair policies are specified to handle the uncertainty of machine breakdowns. The search algorithm for the model is developed, and the numerical example is studied. The computational results and sen...

Assessment of Factors Affecting Building Maintenance and Defects of Public Buildings in Penang, Malaysia

Abstract: This study focuses on the assessment of factors affecting maintenance and defects of public buildings in Penang. The summary of ten relevant factors surveyed from related literatures were tabled and questioned to whom involved in the building maintenance sectors: targeted Public Works Department (PWD) personnel and contractors. SPSS software was used to determine the significance of each factors based on the respondent’s rating. From the analysis study; lack of preventive maintenance, insufficient funds to maintain the building, lack of building maintenance standard, non-availability of replacement part and components and not responded to maintenance request within the 1st to 5th ranking rating of major reasons. While the factors of building defect were also ranked as the most significant factors; i.e. lack of building maintenance, overlooked site conditions, defective material, environment conditions and moisture from wet areas.

Optimizing upgrade level and preventive maintenance policy for second-hand products sold with warranty

Abstract: With the steady growth of second-hand products’ market, offering warranty for second-hand products is becoming popular for dealers in order to meet customers’ requirement. During that process, upgrade actions and maintenance policies are of great importance. In this article, an optimization model for second-hand items sold with non-renewing free repair warranty is proposed from the view of dealers, in which a second-hand product is subjected to upgrade action at the end of its past life and during the warranty period, preventive maintenance actions are carried out when the age of the product reaches a pre-specified threshold value. Optimal upgrade level and preventive maintenance policy are jointly derived so that the dealer’s expected profit can be maximized. The structural properties of the optimal policies are investigated. Finally, a numerical example and sensitivity analysis are provided to demonstrate the proposed approach.