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International Journal of COMADEM

Volume 11, Number 1, January 2008
Special Feature Issue on

Intelligent Materials, Structures & Systems - 3

Modeling of the Visco-elastic Properties of PVDF through the Fractional Differential Model

S. Satiya Narayan, C. Lakshmana Rao and S.M. Siva Kumar; India

Abstract: Polyvinylidene Flouride (PVDF), a piezoelectric material has many useful applications like sensor transducers and surface acoustic wave devices. Since PVDF is a polymer, it is possible that its mechanical response is likely to be frequency and time dependent. It is important therefore, to characterize the frequency or time dependent behaviour of PVDF using appropriate models that are based on experimental observations. In this paper, a four parameter model with fractional dashpot was used and it is found that it models the loss and storage modulus results better than the model with ordinary dashpot.

Key words: Fractional Differential Modeling, Viscoelastic properties,  PVDF; pp 2 - 8; No of References 9.

Structural Health Monitoring of Ribbon Reinforced Composite Laminate using Piezoelectric Sensory Layer

A.K. Jaiswal, A. Kumar and B. Bhattacharya; India

Abstract: The ribbon reinforced composites are widely used in prosthetics. These structures typically work like a bridge between the canines. They are subjected to central loading and also support yielding due to unequal movement of the end supports. However, due to high strains in the laminate, the chances of delamination  and laminate failures are quite high in such structures. In this paper, the finite-element model based development of knowledge-base technique has been used in delamination detection in such composites and which may help in timely replacement of the bridge.

Key words: Structural Health Monitoring; smart plate element; ribbon reinforced composite; delamination in composite laminate. Pp 9 - 17; References 10.

Development of Micromachined Silicon Accelerometers with improved Off-axis Sensitivity

A. Ravi Sankar, S. Das and S. Kal; India

Abstract: Development of micromachined silicon piezoresistive accelerometers with improved off-axis sensitivity has been presented in this paper. Two accelerometer structures have been designed for low off-axis sensitivity. Complete comparative analysis based on simulation results has been given in this paper. Both the structures have been fabricated and testing results of structure 1 have been presented.

Key words: Piezoresistive accelerometers, Off-axis sensitivity,TMOH/CMOS compatibility. Pp 18 - 24. References 26.

Remote Structural Health Monitoring of Civil Infrastructures - Recent Trends

S. Sridhar, K.Ravisankar, P. Sreeshylam, S. Parivallal, K. Kesavan and S.G.N. Murthy; India

Abstract: Construction and maintenance of large civil infrastructures are very much essential for development of any country. The modern constructed facilities involve a huge capital cost and complex design procedures to ensure longer service life and better performance in adverse environmental conditions. There is a growing demand to monitor the health of these structures to increase its safety and serviceability. Remote health monitoring (RHM) is a recent methodology, whereby the instrumented structure is continuously monitored from a distant place, using the latest communication and IT tools. This paper discusses the various aspects of RHM techniques, the latest development in software and hardware.

Key words: Remote Health Monitoring, wireless communication, GSM/RF/PSTN.MOTES, Data acquisition, Embedded algorithms, Civil Infrastructures. Pp. 25 - 35. References 26.


Volume 11, Number 2, April 2008

Advanced Vibration Analysis to Support Prognosis Rotating Machinery Components

M.J. Roemer, C.S. Byington and J. Sheldon; USA

Abstract: Advanced vibration analysis technologies that provide incipient fault detection to enable longer time horizons for failure prediction of critical machine components (prognostics) has the potential to significantly reduce maintenance costs and increase availability and safety. This paper summarizes a comprehensive approach to enhancing prognostic accuracy through more intelligent utilization of relevant vibration diagnostic information coupled with advanced physics-of-failure modelling. Failures and associated predictions of critical rotating machinery components are used as a case study to introduce the concept of adapting key failure mode variables at a local damage-site based on fused vibration features. The overall prognostic system architecture is focused on minimizing inherent modelling and measurement uncertainties by updating material/fatigue properties; spall propagation rates etc., via sensed system measurements that evolve as damage progresses. A specific case study related to aircraft engine rolling element bearing is presented.

Keywords: Machinery diagnostics, prognostics, rolling element bearings, vibration analysis;

Pp 2 -11; References 10.

Energy Losses caused by Misalignment in Rotating Machinery: A Theoretical, Experimental and Industrial Approach

E. Estupinan, D. Espinoza and A. Fuentes; Chile

Abstract: This paper deals with one of the most common malfunctions in rotating machinery, namely Misalignment. Several studies have shown that misalignment produces at least 30% of the faults caused by vibration. In this paper, an analysis of energy losses generated by misalignment in rotating machinery has been carried out, with the main objective of finding a correlation between vibration levels and energy consumptions for different degrees of misalignment. A laboratory test rig has been implemented to carry out experimental work for various degrees of misalignment. Two industrial case studies, one from a mining company and the other from a thermoelectric company have been included. A statistical model based on the response surface methodology (RSM) was employed for the data analysis. A simplified economic study illustrates the industrial benefits when a predictive and preventative methodology is implemented.

Key words: Shaft misalignment, Energy loss monitoring, response surface methodology. Pp 12 - 18. References 11.

Dynamics of Large Power Turbo-Set with Cracked Shaft

S. Banaszek; Poland

Abstract: This paper presents the research and the results of crack propagation simulation investigation. The object of this investigation is to take into account of a large turbo-set rotor. A computer code system NLDW is presented. This uses a non-linear model of journal bearings, and a well known crack model. Crack depth is represented by a crack coefficient. It is shown that a crack generates a coupled form of lateral, axial and torsional vibrations in multi-support rotor. Its intensity depends upon the axial and angular crack location on the shaft. An attempt is made at pointing a proper diagnostic indicator for crack detection in large rotating machine.

Key words: crack propagation, large power turbo-set, cracked shaft, crack model. Pp 19 - 28. References 24.

A New Recursive Structure-Adaptive Filter for Impulse Noise Removal

S. Md. Mansoor Roomi, V. Abhaikumar and T. Krishnan; India

Abstract: A new recursive structure-adaptive filter for effective suppression of impulse noise is presented in this paper. In the first stage, at every noise location in a corrupted image the structure activity is identified by quadratic decomposition. Based on the local structure activity and noise statistics, a recursive window adaptive filtering mechanism is proposed to switch between simple mean, median and centre weighted median filters to provide detail preserving filtering of corrupted pixels. Extensive simulation shows that the proposed filter restores fairly well even when the images are highly corrupted.

Key words: Impulse noise, Structure activity index, discrete cosine transform. Pp. 29 - 35. References 23.

Core Concepts and Technologies of Machinery Oil Analysis for Performance Excellence and Failure Prevention

S. Li and V. Palekar; USA

Abstract: Machinery oil analysis (MOA) is a tribology and lubricant based maintenance  tool and failure prevention technology for machinery systems. Once as a practice-focused enabling technology for machinery condition monitoring, MOA is currently advancing to shape its characteristic conceptual framework and technological system. The core concept of MOA is expressed by a triangle representing machinery system contamination, component part wear, and oil physical chemistry respectively. This concept, as a whole or in part, has been gaining wider and wider real-world applications. The uniqueness of this concept in the roles it plays in setting up application-oriented MOA facilities, designing case-sensitive MOA profiles, conducting MOA data-based root-cause analysis, and diagnosing machine/oil health status. In this paper, accounts have been made of the historical evolutions of MOA application phases, technology milestones, instrumentation modes, laboratory types , practice features, parameter characteristics, and service forms.

Key words: Machinery Oil Analysis, condition monitoring, Lubrication management, Tribology. Pp 35 - 42. References 18.

Volume 11, Number 3. July 2008

A Reconfigurable Watchdog Agent for Machine Health Prognostics

L. Liao, H. Wang and J. Lee; USA

Abstract: This paper presents a scalable Watchdog Agent-based toolbox approach for machine health prognostics. The toolbox consists of modularized embedded algorithms for signal processing and feature extraction, performance assessment, diagnostics and prognostics, which can be reconfigured for different machinery prognostic applications, and can be extensible and adaptable to most real-world machine situations. A decision making technique, Quality Function Deployment (QFD)- based tool section method, is applied for the automatic selection of algorithms from the Watchdog Agent toolbox using multiple criteria. In addition, the architecture for the Watchdog Agent-based real-time remote machinery prognostics and health management, which incorporates remote and embedded predictive maintenance technologies, is presented. An industrial case study involving the automatic tool changer of a machine tool is presented to illustrate how the Watchdog Agent toolbox can be used in diverse scenarios.

Key Words: Watchdong Agent, Toolbox, Machine health monitoring, diagnostics, prognostics. Pp 2 - 15. References 30.


Effects of Couple Stresses in Rolling and Normal Motion

R. Raghavendra Rao and K. Raja Sekhar; Eritrea and India

Abstract: Generally, a small amount of additives are added to the lubricant to increase its efficiency in the lubrication process. Usually, these additives are in the form of long-chain molecules. These produced couple stresses and also have an affect on the lubrication process. A generalized Reynolds equation is derived for roller bearings lubricated by couple stress fluid as a lubricant under dynamically loaded condition. This equation is applied to study the effect of couple stresses on the combined rolling and normal motion under cavitation boundary conditions. The load capacity, frictional drag are analysed by velocity ratio parameter and also the effects of couple stress of these parameters on cavitation point is discussed.

Key words: Rolling and normal motion, Couple stresses, Frictional drag, cavitation points. Pp 16- 22. References 19.

Computer Interface for Tapered Roller Bearing Diagnostics

A. Andhare and D. Manik; India

Abstract: This paper presents details of a computer interface developed for vibration monitoring and diagnostics of tapered roller bearings, based on experiments conducted for bearing fault diagnosis. An experimental set up was designed and fabricated for testing various tapered roller bearings to obtain their vibration characteristics - three defect-free and nine defective tapered roller bearings were tested. The defective bearings tested were: bearings with outer race defects, roller defects and combination of both. The bearing vibration data were acquired using NI DAQ and LabView Virtual Instrumentation Software, which were further processed using computer interface developed for diagnostics. The computer interface used various time and frequency domain parameters like: peak to valley, RMS value, kurtosis, skewness, envelope analysis, etc. to diagnose faults in bearings. The interface was able to diagnose point defects in the tapered roller bearings. The above computer interface, with some modifications can as well be used for diagnosing defects in plain roller bearings also.

Key words: Tapered roller bearings, Failure diagnosis, Computer interface. Pp 23 - 35, References 32.

Volume 12, Number 3, July 2009

Detection of Crack in Vessels by Monitoring Changes in Natural Frequencies

Choubey, A, N. Tandon and D.K. Sehgal

Abstract: When significant damage occur a change in stiffness occurs which affects natural frequency. In this paper the authors present the reduction of natural frequencies of vessel structures due to the presence of cracks. Finite element analysis has been used to obtain the dynamic characteristics of intact and damaged structures for the first five modes. Two kinds of vessels (boiler and storage tanks) were chosen as test structures. Models of vessels were prepared and boundary conditions (which were closely resembled original strucutes) were applied to the models.  Acceleration frequency response functions were monitored at different points on each model by changing crack sizes and locations.

Key Words: Structural monitoring, vessels, crack investigation, FEM.

Number of pages: 5; References; 4.

Health Assessment of Mechanical Systems

Sharma, B.C.

Abstract: A procedure based on digraph and matrix method is suggested to assess the health of mechanical systems. Node in the digraph represents the health parameters and their interrelations are represented by the edges. A one to one matrix (also known as Permanent Matrix) is used to define the health function of the system. From this the Health Index of the system is derived. A higher value in the Health Index implies good health of the system.

Key Words: Health assessment, Mechanical systems, Health Index, Digraph, Graph Theory.

Number of pages: 8; References: 11

Increased Safety Protection and Energy Conservation for Motors installed in Zones 1 and 2 Hazardous Areas using Variable Speed Drives

B. Ahirwal, A.K. Singh, R.K. Vishwakarma and A. Sinha

Abstract: Energy efficient motors with variable speed drives (VSDs) differ from other types of motors in a number of ways. Where increased safety, better performance and energy savings are concerned these motors are the most preferred solution.  This paper describes the application of these motors in the Indian mining industry.

Key Words: Variable Speed Drive motors; Indian Mining industry

Number of pages: 9; References: 3


Motor Fault Classification using Wavelet Energy and Artificial Neural Network

P. Dubey and C. Sujatha

Abstract: In this paper the authors investigates the vibration and motor current signatures using Wavelet Transform for feature extraction and Artificial Neural Networks (Error Back Propagation type) for classification of electrical and mechanical faults in a three-phase induction motor. Three sets of electrical and mechanical faults (such as bearing faults, rotor unbalance, rotor bar damage, single phasing and stator winding short) have been investigated on a 5 HP induction motor.

Key Words: Induction motor failures, application of Wavelet Transforms and ANNs

Number of pages; 6; References; 11

Quality Improvements at an Automobile Components Manufacturing Plant: A Case Study

D. R. Jana and A.P. Singh

Abstract: In this paper the authors investigates the implementation of Statistical Process Control (SPC) techniques at a washer manufacturing plant.

Key Words: Automated Process Control; Process Capability; Pareto Analysis; Cause and Effect Analysis

Number of pages; 9; References; 11

Volume 12, Number 4, October 2009

Dynamic Modelling and Empirical Mode Decomposition of Spur Gear Vibration for Early Detection of Cracks

Parey, A. And N. Tandon

Abstract: This paper describes a six-degree-of-freedom gear dynamic model including a crack. The model consists of a spur gear pair, two shafts, bearings and inertias representing load and a prime mover. The experimental results support the effectiveness of the gear dynamic model. The authors propose a method for early detection of defects.

Key Words: Gear vibration, dynamic modelling, crack detection. Empirical mode decomposition, Kurtosis

Number of pages: 8; References; 9

Essential Information forms of Condition Monitoring in a Condition Based Maintenance Context

Carina Andersson and M. Bengtsson

Abstract: In this paper the authors discuss an important aspect of information theory to achieve some benefits in the context of condition based maintenance of industrial assets. A case study is presented on four Swedish paper mills and one condition monitoring equipment supplier. The outcome of this study resulted in a framework that visualizes how data and five different forms of information interacts to yield knowledge about the condition of machines.

Key Words: Information theory, Condition based maintenance, Case study on Swedish paper mills

Number of pages: 11; References; 43

A Neuro-Fuzzy System for Thermal Ageing Prediction of Paper/Oil Transformer Insulation Properties

L. Mokhnache, A. Boubakeur, P. Verma and R. Kattan

Abstract: In this paper the authors have applied a neuro-fuzzy system to predict thermal ageing of oil/paper transformer insulation. The fuzzy system is coupled with a Radial Basis Function Neural Network to investigate the physical phenomena leading to a sudden change in the behaviour of the insulation property of paper/oil transformer.

Key Words: Thermal ageing; paper/oil transformer insulation; neuro-fuzzy system

Number of pages; 4; References; 9

Rolling Element Bearing Fault Diagnosis using Adaptive Morlet Wavelet Filter

Verma, A.K. and B. Sreejith

Abstract: The impulses generated by the roller element bearings are relatively of low energy spread over a wide frequency bandwidth. These periodic impulses may be modulated and masked by noise. This paper discusses the application of a method using Morlet Wavelet Filter (MWF) for diagnosing the bearing failures. The parameters of the Morlet wavelet are optimised using Shannon Entropy and Kurtosis. The results obtained are promising.

Key Words: Rolling element bearing, localized defects, diagnosis, Morlet Wavelet Filter

Number of pages 8; References 21

Ontologies for Condition Monitoring and Maintenance

J. Compos

Abstract: Ontology plays a very important role in knowledge sharing, reuse and communication. The paper discusses this subject under three headings; repository ontology, software application ontology and user interface ontology. A short description of the use of software application ontology and the user interface ontology in the field of condition monitoring and maintenance management is presented in this paper.

Key Words: Ontology; Condition monitoring; Maintenance management

Number of pages 7; References 41

Volume 13, Number 1, January 2010

Special Feature Issue on: Structural Health Monitoring

A Review of Impact Damage Detection in Structures using Strain Data

Mujica, L.E., J. Rodellar and J. Vehi

Abstract: This paper aims to provide a state-of-the-art review on impact damage detection techniques in structures using strain data. An overview of impact detection systems is provided. These include sensors, specimens, and impact sources used for developing and testing strategies. This review focuses on approaches that use impact strain data to determine simultaneously the location of an impact at the time it occurs. These approaches are classified into two groups; one based on analytical models and the other based on data-driven models.

Key Words: Impact damage detection; Structural health monitoring, strain models

Number of pages 16; References 92

Leak Detection in Pipes using Induced Water Hammer Pulses and Cepstrum Analysis

Taghvaei, M., S.B.M. Beck and J.B. Boxall

Abstract: Leakage from pipes transporting fluids, such as water distribution networks or oil transport pipelines is a major problem throughout the world. One promising approach to identifying leakage points has been to analyse the reflections from a pressure wave caused by shutting a valve, using a wavelet to filter the data followed by a cepstrum to extract the reflection points. The work reported in this paper takes this technique and applies it to a laboratory based pipe test facility. A novel device is also reported for the creation of the water hammer pulse and the acquisition of the reflected signals from the pipe system. Results reveal that the signal analysis approach combined with the device is able to identify the leaks in the large diameter pipe to accuracy better than one quarter of a metre. When the four thirds power of the amplitude of the processed peak was plotted against leak rate, a straight line was produced, indicating that not only position, but also leak rate can be identified using this technique.

Key Words: Condition monitoring, leaks in pipes, water hammer pulses, Cepstrum analysis

Number of pages 7; References 21

Quantitative Structural Health Monitoring by Ultrasonic Guided Waves

Srivaastava, A. and F. Lanza di Scalea

Abstract: This paper presents a Global-Local (GL) method to simulate the interaction of ultrasonic guided waves with structural defects in plate-like structures. The GL method uses a Full Finite Element discretization of the defected region to properly represent wave diffraction phenomena and a suitable set of wave functions to simulate regions away from the joint. Displacement and stress continuity conditions are imposed at the boundary between the global and the local regions. The radiated wave field can then be calculated by using the least square method. The novelty of the proposed approach over previous GL techniques is the use of Semi Analytical Finite Element (SAFE) modelling for the “global” simulation and the use of this technique to quantify defects by guide waves. The SAFE method only requires the discretization of the waveguide’s cross-section in a computationally efficient manner.

Key Words: Structural health monitoring, plate-like structures, ultrasonic guided waves, Semi Analytical Finite Element (SAFE) modelling

Number of pages 8; References 18

Vibration-based Structural Damage Identification using Active sensing to measure Internal Forces that represent Damage in a Honeycomb Panel

Adams, D.E. and J.R. White

Abstract: This paper uses a vibration based structural damage identification technique which represents damage as a change in the internal mechanical forces within a structural component.  To validate the method, an analytical two degree of freedom model is first developed to provide the physical insight  into the meaning of the damage indicators, which are extracted from measured data. The results from this model are then compared to the numerical results from a finite element model of a free-free metallic beam and experimental results from a modal vibration test on this beam. After establishing the agreement between theoretical and experimental damage indicators for this simple beam structure, the methodology is applied to a more complicated A1-A1 sandwich structure with a honeycomb core. The experimental results on the sandwich panel demonstrate that impact damage can be detected, located and quantified. A final experiment is then conducted by loosening the piezoelectric actuator attachment causing a change in the resulting damage indicator. This falsie indication of damage is then suppressed by tuning the actuator force signal automatically based on the frequency response measurement between the driving voltage and measured input force to the panel.

Key Words: Structural health monitoring, vibration-based damage identification, honeycomb panels.

Number of pages 13; References 11

Wave Propagation Modelling for Structural Damage Detection

W. Ostachowicz, M. Krawczuk, A. Zak and P. Kudela

Abstract: This paper presents some results of the analysis of elastic wave propagation in one-dimensional and two-dimensional elements of structures with damage. The problem of elastic wave propagation has been solved by the use of the Spectral Element Method. In this approach elements of structures are modelled by a number of spectral finite elements with nodes defined at appropriate Gause-Lobatto-Legendre points. As approximation polynomials high order orthogonal Lagrange polynomials have been used. In order to calculate the elements characteristic stiffness and mass matrices the Gauss-Lobatto quadrature has been applied. In the current analysis damage in the form of crack has been considered. It has also been assumed that the damage can be of an arbitrary length, depth, and location and can be simulated as a line spring of varying stiffness. Numerical calculations illustrating the phenomena of elastic wave propagation in isotropic and orthotropic media have been carried out for the case of a rod and a beam, as well as a flat panel and a plate. Certain results related to a damage detection algorithm developed by the authors have also been shown and discussed.

Key Words: Elastic wave propagation, one-dimensional and two-dimensional structural elements, spectral element method, damage detection

Number of pages 16; References 47

Volume 13, Number 2, April 2010

Special Feature Issue on Knowledge-based Failure Diagnosis and Prognosis of Engineering Systems

Towards a rapid considerable Embedded Development for Manufacturing Prognostics: A Review and Proposed Framework

Kia Mok Goh, Benny Tjahjono and Tim Baines

Abstract: With the fast changing global business landscape, manufacturing companies are facing the increasing challenge to reduce the cost of production, increase equipment utilisation and rapidly provide innovative products in order to compete with low cost economies. One of the methods is zero or near zero downtime. Unfortunately, the current research and industrial solutions do not provide a user friendly and rapidly configurable environment to create ‘adaptive microprocessor size with supercomputer performance’ solution in order to reduce downtime. Most of the current solutions are PC-based with off-the-shelf software tools, which are found to be inadequate for adaptive prognostics near the sensor source using embedded devices. On the other hand, developing a solution for various industrial domains can be too time consuming because  the tools and rapid methods for creating adaptive or real time reconfigurable solutions are lacking. A total of 175 papers , rom 38 refereed journals and international conferences are collated and reviewed. Based on the review, some of the potential industrial needs, research trends and gaps in manufacturing prognostics are discussed. Finally, a research agenda towards a rapid configurable embedded development environment  for manufacturing environment is identified.

Key words: Manufacturing prognostics, embedded development

Number of pages 15; References 62

A Two-stage Neural Network Classifier for Condition Based Maintenance in Wireless Sensor Networks

Ramani, A. C. McMurrough, M. Middleton, P. Ballal, A. Athamneh, W. Lee, C. Kwan and F. Lewis

Abstract: Motor failures in aerospace applications can lead to serious compromises in safety, overall effectiveness, and maintenance costs. In mission critical applications, it is important that motor fault signatures are identified before a failure occurs. It is known that 40% of mechanical failures occur due to bearing faults. Bearing faults can be identified from the motor vibration signatures. Three key contributions are outlined in this paper. First, we develop a low cost test bed for simulating bearing faults in a motor. Second, the authors develop a wireless sensor module for collection of vibration data from the test bed. Finally, The authors use a novel two stage neural network to classify various bearing faults using the Generalized Hebbian Algorithm (GHA) in the first stage and a supervised learning vector quantization network (SLVQ) with a self organizing map approach for fault classification in the second stage.

Key Words: Condition based maintenance, bearing failures, artificial neural networks

Number of pages 8; References 45

Sensorless Detection of Cavitation in Centrifugal Pumps

P.P. Harihara and A.G. Parlos

Abstract: Electrical signal analysis (ESA) has been in use for quite some time in detecting faults occurring in induction motors. In industrial applications, the induction motors are always coupled to dynamic loads such as pumps, blowers, compressors, etc. Failure to either the motor or the dynamic load is critical to the operation of the plant and results in loss of production and unscheduled downtime leading to increased costs. Hence there is a need for a cost effective early failure detection system not only for induction motors but also for the dynamic loads connected to the motor. In this paper, an experimentally demonstrated model-based sensorless approach to detect varying levels of cavitation in centrifugal pumps is presented.

Key Words: Sensorless detection, cavitation, centrifugal pumps

Number of pages 7; References 6

Identification of precursory Alarm Sequence Patterns for Predicting equipment failures using Ant Colony-based Algorithm

M.Luo, D.H. Zhang, L.L. Aw and F.L. Lewis

Abstract: In industry, enormous files of historical data are collected from equipment monitoring prior to failures. The search for reliable precursory alarm patterns, that is, specific sequences of alarm events, in such data sets is a challenging task. This paper describes an algorithm for identifying precursory alarm patterns from historical measured event data containing numerous fault alarms and equipment states. The algorithm is based on modifications to ant colony optimization (ACO), which is an effective probabilistic learning method for finding shortest paths in large complex graphs. An actual industry application is used to verify the algorithm.

Key Words: Alarm sequence patterns, ant colony based algorithm

Number of pages 12; References 16

Intelligent Diagnostic Health Management of Power Transmission Systems: An Experimental Validation

Onsy, A. R. Bicker and B. Shaw

Abstract: Power transmissions are one of the most important parts of any mechanical system, and in order to achieve reliable operation robust and effective maintenance strategies must be used to trace the condition of the operating transmission, classifying faults, and predicting the onset of failure. This paper presents a novel intelligent diagnostic health management system that is able to monitor different gear faults by combining vibration, acoustic emission, and oil debris analysis with fuzzy logic sensory fusion algorithms. The authors have implemented an intelligent diagnostic health management system (IDHMS) on a back-to-back gear box which can be adapted to monitor the behaviour of transmission systems in automotive, aircraft, wind turbine and industrial machinery.

Key Words: Diagnosis of power transmission systems, intelligent diagnostic health management system

Number of pages 13; References 35

Volume 13, Number 3, July 2010

The effect of Shaft Unbalance on the operation of Worm Gear Rolling Bearings

S. Strzelecki and Z. Towarek

Abstract: This paper presents a case study of worm gears coupled to a Cardan shaft. These gears underwent a failure caused by vibration of the roller bearings which are very sensitive to vibration. The damage of such elements leads to gearbox damage. An analysis was done on the machine drive system, the shaft was examined, the natural frequencies of the shaft were calculated and the life of the roller bearings was estimated.

Key Words: Shaft unbalance, worm gear roller bearings, life-cycle estimation

Number of pages 8; References 10

Comparison of Wavelet Coefficients for Condition Monitoring of Ball Bearings using Kolmogorov-Smirnow (KS) test

M.S. Patil, J. Mathew, P.K. Rajendrakumar and S. Desai

Abstract: This paper presents an application of discrete wavelet analysis of the vibration signals to study the effect of damage in ball bearings. Signal to Noise Ration (SNR) and Retained Signal Energy (RSE) of wavelet coefficients of simulated signal was determined using Daubechies Wavelet for four thresholding rules, namely, Rigrsure (SURE), Sqtwolog (S), Heusure (H) and Minimax (M). SNR and RSE values were obtained using simulated signals to select Rigrsure as the thresholding rule and Db8 wavelet as the mother wavelet. This paper explores the possibility of applying the KS test. The feasibility of using this technique is checked by comparing the outcome of the KS test method with that of other statistical methods such as rms, crest factor and kurtosis.

Key Words: Diagnosis of ball bearings, Kolmogorov-Smirnov (KS) test

Number of pages 8; References 18

eMaintenance readiness of Swedish Process Industry: A Case Study

R. Karim and A. Parida

Abstract: The industries are focusing more on e-business intelligence in managing their assets. This is putting increasing pressure to minimize the downtime and improve the performance of their assets. The purpose of this paper is to undertake a mapping of the present status of the maintenance of Swedish Process Industry in order to identify the feasibilities and challenges for implementing eMaintenance system.

Key Words: e-Maintenance, Swedish Process Industry

Number of pages 7; References 13

Evaluation of Unbalance and Misalignment effect on Forward Curved Centrifugal Blower using Coast-down Time Analysis

G.R. Rameshkumar, K.P. Ramachandran and B.V.A. Rao

Abstract: In this paper unbalance and misalignment effects are investigated experimentally in forward curved centrifugal blower test rig using coast down time analysis as condition monitoring parameter. The results are analysed to assess the potential of using Coast Down Time (CDT) as a diagnostic tool for detecting these conditions.

Key Words: Forward curved centrifugal blower, unbalance, misalignment, coast down time analysis

Number of pages 11; References 18

Condition Monitoring of Railway Switches and Crossing by using Data from Track Recording Cars

Arne Nissen, A. Parida and Uday Kumar

Abstract: Switches and crossings are vital components within the railway system and contribute to many of the maintenance activities to keep the track section available for traffic. Banverket administers about 12000 switches and crossings which contribute to about 13% of the maintenance budget for Banverket. In this paper using Excel and the track recording car data on level, alignment, cant, curvature and guage have been gathered and analysed.

Key Words: Condition monitoring, railway switches and crossings, track recording car, Excel

Number of pages 5; Reference 12

Volume 13, Number 4, October 2010

Special Feature Issue on Energy and Environment

Future Transportation with Smart Grids and Sustainable Energy

G.R. Grob

Abstract: Transportation is facing fundamental change due to the raped depletion of fossil fuels, environmental and health problems, the growing world population, rising standards of living with more individual mobility and the globalization of trades with its increasing international transport volume. To cope with these problems benign, renewable energy systems and much more efficient drives must be multiplied as rapidly as possible to replace the polluting combustion engines with their much too low efficiency and high fuel logistics cost. Consequently the vehicles of the future must be non-polluting and super efficient. The energy supply must come via smart grids from clean energy sources not affecting the health, climate and bioshphere. It is shown how this transition to the clean, sustainable energy age is possible, feasible and most urgent.

Key Words: Sustainable energy, environmental protection, smart grid

Number of pages 6; References 6

Augmentation of Heat Transfer Coefficient using Chamferred Rib-grove Compound Roughness on Absorber Plate of Solar Air Heater

Apurba Layek

Abstract: An experimental investigation into the heat and fluid flow characteristics of a fully developed turbulent flow in a rectangular duct having repeated integral transverse chamfered rib-grove roughness on one broad wall has been carried out. The roughened wall was uniformly heated while the remaining three walls were insulated. The flow Reynolds number of the duct varied in the range of approximately 3000 - 21000. Experiments were carried out on 61 roughened surfaces provided with chamfered rib grove roughness having relative roughness pitch of 4.5, 6. 7, 8 and 10 and chamfer angle of 50, 120, 150, 180, 220 and 300, while 600 V groove were placed by varying the relative groove positions 0.3, 0.4, 0.5 and 0.6. The effects of relative roughness height and duct aspect ratio were kept constant at 0.03, 5 and 10 respectively. The effects of relative roughness pitch, chamfer angle and relative groove position on Nusselt number and friction factor have been discussed.

Key Words: Turbulent flow, rectangular duct, heat transfer coeffient, solar air hearter

Number of pages 8; References 13

A different approach to Economic Load Dispatch of Thermal Power Plants using Exponential Cost Function

M. Mohatram, P. Dhyani and P. Tiwari

Abstract: In this paper the problem of Economic Load Dispatch (ELD) in power systems is resolved by considering the operating cost of a thermal power plant as an exponent function. Equality constraints of power balance and inequality plant generation capacity constraints are taken into consideration. The problem is formulated with the transmission losses in the lines and is solved by Lagrangian approach of equal incremental cost. The results of the proposed method are tested for a system consisting of six generating units and the results are compared with a similar problem having quadratic cost functions. Finally the significance of the proposed method is highlighted.

Key Words: Economic Load Dispatch, power systems, exponential cost function

Number of pages 6; References 15

When will Fossil Fuels finally run out and What is the Technical Potential for Renewable Energy Resources?

Stas Burek

Abstract: Reserves to Production  ratios (R/P) are widely used indicators of the time to depletion of fossil fuel resources. But they are not reliable indicators of the longevity of fossil fuels. This paper examines historical data from 1985, relating to proven resources of fossil fuels and trends in consumption. Based on the increase in consumption as well as reserves, the conclusion is that the current trends suggest that all fossil fuels (oil, gas and coal) could be depleted within decades, possibly as early as 2060. The annual solar energy incident on Earth is some 13500 times more than the annual commercial consumption, and various ideas have been put forward to harness the earth’s renewable flows of energy on a major scale. This paper reviews some of these ideas and examines the technical potential for renewable energy to become a major energy resource in the future.

Key Words: Fossil fuels, renewable energy resources, historical data analysis

Number of pages 6; References 12

Modelling Industrial Energy Flow on a National Scale

Nesrin Ozalp

Abstract: This paper describes possible means of modelling industrial energy flow on a national base, along with discussions on how useful they would be for better utilization of energy and enhanced policy making. Models for energy inputs and allocation of them among specific end-uses in various US manufacturing industries are given as examples. The energy types included in the given end-use models are: fuel, steam, waste heat and electricity. These models provide a useful tool to characterize industrial energy usage. Similar energy end-use models can serve as key for other studies such as energy process-step models and energy cost analysis for manufacturing industries.

Key Words: Industrial energy flow, modelling

Number of pages 9; References 23

Volume 14, Number 1, January 2011

Special Feature Issue on Failure Diagnosis and Prognosis of Mining Machinery & Systems

Shovel Teeth monitoring and Maintenance in Open-pit Mines

H. Schunnesson, H. Mwagalanyi and Uday Kumar

Abstract: Significant problems exist during the loading of ore in open-pit mines. The problems arise when parts from the bucket follow the ore into the crusher pit causing jamming and damage to the crusher. Repairing this is not only time consuming and very expensive. In this paper a system for detecting the broken teeth and adapters based on infrared images is investigated.

Key Words: Open-pit mining machinery, shovel teeth monitoring

Number of pages 8; References 6

Dragline Maintenance Data Analysis using Logarithmic Scatterplot

S. Elevli, O. Uysal and B. Erdem

Abstract: In this paper maintenance data of two draglines is analysed using Logarithmic Scatterplot method. The data gathered in this investigation reveal how to prioritize maintenance of mechanical and electrical sub-systems of draglines. The boom, hoist rope and attachments, swing, drag and hoist machineries have been identified as priority components for mechanical sub-systems. Likewise the drag, hoist, swing and propel motor and generator sets have been identified as priority components for the electrical sub-system.

Key Words: Dragline maintenance, data analysis, logarithmic scatterplots

Number of pages 7; References 21

Importance of Measure based Ranking and Maintenance Scheduling for Heavy Duty Belt Conveyors: A Case Study from underground Coal Mine

Suprakash Gupta

Abstracts: This paper focuses on the maintenance scheduling for production equipment keeping cost control as the primary objective. It highlights prioritization of resources and the importance of the measure based ranking of components and sub-systems. A cost-effective measure has been proposed for scheduling various maintenance tasks.

Key Words: Underground Coal mines, Heavy duty conveyors, measure based ranking procedure

Number of pages 8; References 44

Establishing a Dragline Monitoring System at Kleinkopje Colliery

E.B.M. Carpenter

Abstract: This paper discusses the process undertaken by the Kleinkopje Colliery to establish a reliable and effective monitoring system on its fleet of walking draglines. The paper highlights the process of monitoring system selection, site establishment, commissioning and also gives an outline of current and future uses of the monitoring system. It also focuses on the background, setting up details, results and future perspectives of an efficient monitoring system in a large and prestigious opencast colliery.

Key Words: Opencast colliery, walking draglines monitoring

Number of pages 7; References 6

Productivity Diagnostic study of Draglines operating in Horizontal Tandem

Piyush Rai

Abstract: This paper reports the investigation undertaken in a large Indian opencast coal mine to critically investigate the horizontal tandem operation of draglines for removing moderately hard and blasted sandstone bench. The paper outlines a methodology to determine the efficiency of dragline operations and to diagnose the key operating parameter that influences its efficiency.

Key Words: Indian opencast coal mines, failure diagnosis of draglines

Number of pages 6; References 11

Volume 14, Number 2, April 2011

Special Feature Issue on Failure Diagnosis and Prognosis of Swedish Mining Assets

Evaluation of Abrasive Wear Measurement Devices of Mill Liners

R. Dandotiya, J. Lundberg and A.R. Wijaya

Abstract: Measurement of the liner wear in the mill of an ore dressing plant is one of the critical parameters in the context of mill downtime and production performance. Due to the different quality attributes of a measuring device, e.g. cost, accuracy, reliability and accessibility, it is necessary to select an important performance measure for the service quality of the device. This paper provides an approach to customer satisfaction with special reference to quality attributes. The primary aim of this investigation is to provide unified measure or quality index which corresponds to the total predicted usability of the particular measurement method. The paper also proposes a new concept of an indirect measurement method to reduce downtime during inspection.

Key Words: Mill liner abrasive wear, diagnosis and prognosis

Number of pages 15; References 26

Non-Destructive Testing methods for Detection and Monitoring of Fatigue Cracks in Mining Mills

F. Berglund, J. Nordstrom and A. Parida

Abstract: The mining industry is striving for higher production and to maximize the availability of its machinery. Smart diagnosis and prognosis of mill machinery operations is vital to minimise unplanned stops, expensive failures, production loss and breakdowns due to fatigue cracks, especially in the mill shell. The aim of this paper is to highlight the scopes and limitations of the different crack detection methods. The authors have applied analytical hierarchical process (AHP) to determine the rank or unified measure for the selected crack detection methods.

Key Words: Mining mills machinery, condition monitoring and diagnosis

Number of pages 9; References 25

Condition Monitoring and Maintenance Performance Assessment issues for Mining Industry

Aditya Parida

Abstract: Maintenance performance assessment of mining industry is a complex issue as it involves various stakeholders both internal and external. In this paper the author discuss various condition monitoring and maintenance management issues relating to mining industry.

Key Words: Mining industry, issues and challenges, condition monitoring, performance assessment

Number of pages 8; References 31

Enhancement of Mining Machinery Performance through Supportability

B. Ghodrati, T. Markeset and A. Ahmadi

Abstract: Cost analysis of mining operations in general shows that 30 to 50 percent of direct mining costs are related to maintenance and losses related to lost production during equipment downtime. To reduce these losses one first needs to improve the equipment reliability and thereafter to reduce the downtime losses through improved maintainability and supportability. The mining operational environment is often harsh and may severely impact all three of these abilities.  In this paper the authors focus on how to improve the estimation of spare parts by taking into account the operating environment in the estimation models. In this investigation the authors have developed an improved statistical-reliability (S-R) analysis approach that takes into account the system/machine operating environment. This analytical approach is based on multiple regression based on Cox’s proportional hazards modelling (PHM).

Key Words: Mining machinery, performance monitoring, proportional hazards modelling

Number of pages 9; References 16

Rock Mass Characterisation using Drill and Crushability Monitoring: A Case Study

H. Schunnesson and T. Kristoffersson

Abstract: This paper presents the application of drill and crushability monitoring to predict detailed rock mass characterisation in the Swedish surface copper mine (Aitik). Both monitoring methods can provide relevant rock mass information to support production and production planning. Furthermore the necessary geometrical connection between drill hole position, loading position and the related crushing activities later in the process can be solved by the mine planning system, MineStarTM

Key Words: Copper mining operation, drill and crushability monitoring

Number of pages 9; References 15

Volume 14, Number 3, July 2011

Lean, Clean, Green and Intelligent infrastructure for Sustainable Cities