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A framework for improving pump reliability and availability in air separation industry

  • Authors: Maphosa, Ibo
  • Date: 2017
  • Subjects: Pumping machinery industry , Gases - Separation , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/269843 , uj:28671
  • Description: M.Ing. (Engineering Management) , Abstract: The quest for a sustainable Asset strategy is gaining substantial momentum in modern day enterprises, especially in air separation plants where hundred percent process reliability and plant availability is no compromise. In order to achieve such levels of operational excellence and integrity, Asset strategy and equipment maintenance strategy systems must be properly integrated. Although many different maintenance programmes exists in the current industrial domain, unintended downtime due to failures of centrifugal pumps remains a major source of downtime in air separation plants. This phenomenon is investigated here in the context of the implementation of reliability centred maintenance (RCM) framework in air separation environment, based upon the available organisational standards and processes. The main objectives of this study are to identify the factors that affect centrifugal pump reliability and identify the ways to improve the reliability of centrifugal pumps in air separation industry. Two Case studies (plants) in the same company were selected for this research. The case study method was considered the appropriate method for this research. This was based upon the type of the research questions posed and in-depth understanding of business operational processes the method provides to the candidate. Computer Assisted Qualitative Data Analysis (CQADAS) software (ATLAS.ti Version 8) was used to analyse the data from the participants. All the questionnaires that were completed by the participants were loaded into the data analysis software. Data reduction, data coding, grouping and theme generation was accomplished. It was found that effective two-way communication or lack thereof between the plant personnel and the Reliability Engineers affects knowledge sharing and quality of pump strategies. An updated RCM framework and an asset strategy model that was developed provide the clarity and improvement of communication that is required to improve centrifugal pump reliability.
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A mechanistic dynamic simulation for predicting the bottom of the line corrosion rate of mild steel in metal mine effluent and synthetic seawater flow

  • Authors: Mothiba, Matsobane Phillip
  • Date: 2020
  • Subjects: Alloys - Corrosion , Reliability (Engineering) , Hydrodynamics
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/480440 , uj:43493
  • Description: Abstract: This study was structured on the uncertainty of events that comes with internal pipe corrosion. Hitherto, the study of corrosion was structured on the combined effect of electrochemical activities (chemical dissolution) and flow properties (hydrodynamics) being the main parameter controlling the physical characteristics by forming semi-permeability or partial protective corrosion product barrier between the steel surface and the flowing MME/SSW solution. To disseminate the knowledge and raise the level of understanding, a multi specimen electrochemical test-rig prototype was developed to study the corrosion behaviour of mild steel in mine effluent (MME) and synthetic seawater (SSW). The electrochemical impedance spectroscopy (EIS) data showed the SSW corrosion-product charge transfer resistance (R2) decreased from 18597 Ohm to 3.367 Ohm with flow rate. The lower the charge transfer resistance indicates a high mild steel dissolution rate. Hence, a decrease in charge transfer (R3) with exposure time. The MME experiments were marked by a low charge transfer resistance (R3), hence the high corrosion rate (CR). The (a) factor indicated the permeability of the multi-layered corrosion film, thus, whether or not the multi-layer film behaved like a capacitor. The behaviour was supported by the constant phase element (Q3) which increased with CR... , M.Tech. (Engineering Metallurgy)
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An investigation into the improvement of maintenance quality in a production plant through the use of reliability management

  • Authors: Munzhelele, Fulufhelo E.
  • Date: 2019
  • Subjects: Plant maintenance - Management , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/437484 , uj:37988
  • Description: Abstract: Extensive research has been conducted on plant reliability maintenance. However, getting the maintenance system in place remains the core of maintenance improvement. The purpose of this research dissertation is to investigate the impact reliability management has within production industries and its role in improving the quality of maintenance. This study will assist management to reflect on the costeffectiveness and influence that the maintenance management system has within the organisation. The study will also contribute to existing knowledge in plant reliability maintenance. It is, therefore, significant for an organisation to establish good management practices and set maintenance as an integral part of their overall plant strategy. The approach that was followed by this research is a mixed method – a combination of quantitative and qualitative. Data collection was carried out through a literature review, observations, a questionnaire, a survey, interviews and from company documentation. An employee questionnaire was prepared and distributed to 25 participants to conduct gap analysis and evaluate the maintenance practices within the observed company. A benchmark study was also performed using an online survey, based on 85 responses from employees in other processing plant industries within South Africa. The empirical study conducted with Company A’s employees (mainly from the maintenance and operation departments) identified possible blunders, which transpired during the reliability management system implementation phase. Based on this sample the results obtained indicated that maintenance is done unnecessarily on the plant on average. The study also found issues regarding maintenance financial planning ineffectiveness, unavailability of spares and lack of skillsets to perform jobs. The online survey revealed that organisations do make use of Computerised Maintenance Management System (CMMS) to facilitate their maintenance. CMMS also has a positive impact on the overall maintenance processes and productivity. The study identified the importance of planning and scheduling shutdowns in advance, as a significant part of the maintenance annual budget and cost reduction. .. , M.Phil. (Engineering Management)
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Analysis of factors undermining the reliability of railway track in South Africa

  • Authors: Mukwena, Mulalo
  • Date: 2018
  • Subjects: Railroads - Maintenance and repair , Railroad tracks , Railroads - South Africa - Reliability , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/284872 , uj:30782
  • Description: M.Phil. (Engineering Management) , Abstract: Various factors have been highlighted as causes of reliability deficiency for railway track, globally. It is rather opaque as to which of these factors are prevalent in the South African railway industry. The study develops a framework for identifying and classifying causes of reliability deficiency for Railway Track (also referred to as Permanent way Infrastructure). The researcher employed the exploratory sequential mixed methods; a qualitative research in a form of structured interviews was conducted and the subsequent results were used to build a quantitative research survey through which, the researcher solicited responses from 52 respondents. Target respondents were mainly engineers, project managers, and Technicians experienced in the management of Railway infrastructure. Findings reveal that Poor maintenance policies, strategies and implementations is the most pervasive factor causing reliability deficiency of railway Track in South Africa whilst, Insufficient funding and Aging rail network became the second and third prevalent factors, respectively. The research also concluded, among other things, that; Track components used in South Africa are as good as those used by other major railway organizations globally. The study recommended that; railway organizations in the country should priorities the replacement of old infrastructure, adequate funding should be made available for construction of new railway lines, maintenance and rehabilitation projects, and as part of continuous improvements, railway organizations should realign and modernize their maintenance strategies and implementations.
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Application of reliability engineering in the chemical process plant, to improve reliability and maintainability of equipment

  • Authors: Mamatlepa, Makgomo Thelma
  • Date: 2017
  • Subjects: Chemical plants - Equipment and supplies , Chemical plants - Equipment and supplies - Maintenance and repair , Plant maintenance , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/242393 , uj:24999
  • Description: M.Phil. (Engineering Management) , Abstract: By definition, reliability is the probability that a system (could be equipment, vehicle, machine or even a product) performs its intended function, under specified conditions or environment for a set period of time. The Chemical plant at Company X has been struggling to produce PGM salts in a specified time duration due factors such as equipment failure, process related issues and product quality. This paper addresses the importance and value of reliability engineering to the Company X Chemical plant and reasons for considering reliability engineering more fundamentally in the management of operations and maintenance in the plant. The study focused on production loss; factors that contribute to production loss and reliability theory that can be applied to the plant with special focus on equipment failures. The study achieved the research objectives through an extensive study of literature related to the research topic and implementation of practical research. Practical research was carried out through the collection of empirical data from the day to running of the plant, whereby every production stoppage was captured with causes of the interruption. The study employed qualitative method through review of literature to compare what other authors have discovered about different reliability tools and effective maintenance strategies. A case study method was employed to satisfy the other two objectives whereby data was collected, analysed and interpreted to identify factors that contributes to production loss. The results revealed equipment failures as the main contributing factor to production loss in the plant; this was further broken down to individual vessels to see which ones experience the most failures or have shorter MTTF. The findings of the study revealed further that; in order to improve reliability, availability and maintainability of equipment in the plant, a proper RCM process could add value in the plant. RCM analysis will identify most problematic equipment with most failures, analyse failure modes through FMEA process and suggest maintenance strategies that can be implemented to improve performance of the plant. It is concluded that current corrective maintenance approach in the plant is ineffective because it fails to pre-empt or prevent failures before they occur, instead opting for a more proactive preventative maintenance approach will be cost effective for the company. And that reliability theory should be applied specifically for each plant and not use a holistic approach because plants are unique and operate under different conditions...
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Applying the predictable maintenance approach to DC traction substations in South Africa

  • Authors: Sprong, Willem
  • Date: 2010-03-10T06:20:01Z
  • Subjects: Reliability (Engineering) , Electric railroads substations , Electric substations
  • Type: Thesis
  • Identifier: http://ujcontent.uj.ac.za8080/10210/383805 , uj:6651 , http://hdl.handle.net/10210/3058
  • Description: D. Ing. , This dissertation deals with the important issue of reliability management for 3kV DC Traction Substations used by the national railway company in South Africa. Maintenance is one of the critical and most costly phases in the lifecycle of any plant. It looks at the total life cycle of the equipment in a typical substation, but the focus in the latter chapters is on the maintenance. Through improved maintenance management, the reliability of the system can be improved. The approach to maintenance is addressed as a predictive strategy, avoiding even more costly nonproductive time due to downtime caused by failure or induced by maintenance. Condition monitoring and assessment is described as one of the effective tools in the maintenance engineer’s armoury to apply a predictive approach. A direct link between predictable maintenance and reliability is explored. In the definition of reliability, concepts such as time and expected performance can be linked to a predictable delivery of the designed function. In other words, if down time is expected and can be prepared for, it is more acceptable than the unexpected. In essence, the system is still reliable as it performs according to expectation. The concept of predictable maintenance can be applied wider than just the 3kV traction substation. The process of identifying critical equipment, to measure the condition and to take decisions based on the rate of change in the condition can be used in any maintenance environment, even outside electrical. The crucial ingredient to this is to understand that condition monitoring is not based on fixed values, but the rate at which these values change. This is called Fuzzy logic. Can we predict the future? If yes, how accurate will the predictions be?
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Asset modelling framework for use in computerised physical asset management systems

  • Authors: Henry, C.A.
  • Date: 2017
  • Subjects: Assets (Accounting) - Management , Engineering - Management , Information technology , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/269606 , uj:28642
  • Description: M.Ing. (Engineering Management) , Abstract: The objective of the research is to formulate a simplified physical asset modelling framework that is universal to any industry or any asset type, for use in the chosen Computerised Physical Asset Management System (CPAMS) such that it provides the benefit of improved management of physical assets over its lifecycle. The research highlights that there are numerous CPAMS, whether branded as ERPS, CMMS, EAMS or CFMS as example, however the track record of providing organisational benefit given the significant initial and ongoing investment, is limited. The literature review highlights that the configuration of the CPAMS is one of the contributors to limited benefit, where configuration refers to the structuring and organisation of the CPAMS to do that which the user require. One aspect of the CPAMS configuration is the physical asset modelling framework within which the physical assets are recorded in the CPAMS along with its myriad of data, information and various settings. In addition to that which is entered by the user, the processing of various performances and reporting against the asset modelling framework is equally critical. The development of the physical asset modelling framework involved two independent approaches, firstly deriving a framework from literature review of reliability and logistics engineering theory, and secondly, a framework derived from the research of existing industry asset and asset hierarchy naming conventions, standards or frameworks. The theory-derived framework was validated by the existing industry frameworks with the difference that majority of the existing industry frameworks has an additional organisation level in the hierarchy. A single physical asset modelling framework was derived from the nine existing industry frameworks and since this also validated the theory-derived framework, the industry-derived framework was concluded as the universal simplified physical asset modelling framework. A CPAMS is a necessity for the optimised management of physical assets over its lifecycle to achieve levels of sustained performance required by the organisation’s long-term business strategy and real-time operations. A CPAMS has the potential to realise this optimised management, however, and this is to be emphasised, this potential is only realisable when the CPAMS is configured and maintained by skilled asset management professionals having detailed understanding of what is required for lifecycle asset management, and therefore how the CPAMS must enable this management. This research has developed one such critical requirement which is a universal simplified physical asset modelling framework.
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Case study of preventive maintenance carried out at Sebokeng Hospital in radiology department

Challenges affecting the reliability of diesel locomotives within the South African railway industry

  • Authors: Dibakoane, Kgothlelelo Collet
  • Date: 2013-11-25
  • Subjects: Diesel locomotives - Reliability , Railroads - Dieselization , Reliability (Engineering)
  • Type: Thesis
  • Identifier: uj:7789 , http://hdl.handle.net/10210/8683
  • Description: M.Phil (Engineering Management) , The importance of an effective maintenance programme cannot be over-emphasized because such a programme plays such an important role in the effectiveness of lean manufacturing. Maintenance may be considered the health care of any engineering equipment and its equipment. It is required to reduce waste effectively, and to run an efficient, continuous locomotive operation within a business or service operation. The cost of regular maintenance is very small when it is compared to the cost of a major breakdown at which time production is held up. The main purpose of regular maintenance is to ensure that all equipment required for production is operating at 100% efficiency at all times. Through short daily inspections, cleaning, lubricating, and making of minor adjustments, minor problems can be detected and corrected before they become major problems that can shut down a production line. A good maintenance programme requires company-wide participation and support by everyone from top executives to shop floor personnel (Dale, 2008) The function of reliability engineering is to develop the reliability requirements for a product, establish an adequate reliability programme, and perform appropriate analyses and tasks to ensure that the product meets its requirements. These tasks are managed by a reliability engineer who usually holds an accredited engineering degree and has additional reliability-specific education and training. Reliability engineering is closely associated with maintainability engineering and logistics engineering. Many problems from other fields can also be tackled using reliability engineering techniques (O’Connor 2010). Reliability is defined as the probability that a device will perform its required function under stated conditions for a specific period of time, and quality can be defined as how the recipient of the product or service views the product (Barringer, 2006). Therefore the two cannot be viewed differently as they both have the same focus which is the end result of the product’s performance. The findings reveal that customers should form part of reliability management systems; the development of ways to identify possible failure before it actually happens is key in achieving reliability targets; and training of key personnel on engineering and quality department as well as resource planning and utilization is a key towards eliminating reliability challenges.
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Conceptual development of a centralised support function to facilitate the successful implementation of a reliability centred asset management strategy in a macro coal mining environment

  • Authors: Botha, Dirk Cornelius Petrus
  • Date: 2012-01-16
  • Subjects: Reliability (Engineering) , Maintainability (Engineering) , Total quality management , Plant maintenance , Coal mines and mining
  • Type: Thesis
  • Identifier: uj:1901 , http://hdl.handle.net/10210/4262
  • Description: M.Phil. , The implementation of a maintenance strategy without taking the uniqueness of the specific business into account, will not necessarily result in a high level of performance. The maintenance function should be developed specifically to support the particular business processes and technology in use. There is presently a large gap between the results obtained through the implementation of the maintenance strategy at a major coal-mining complex and the desired targets to be met. To close the gap, this dissertation suggests that support systems should be implemented to sustain growth and stability. The dissertation specifically proposes the creation of a Central Support Function to support the maintenance strategy, which has been implemented together with the Enterprise Management System (EMS) with the System Application Product (SAP) as an enabler.
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Corrugation wavelength fixing mechanism and its relationship to train and track geometry parameters

  • Authors: Balekwa, Bingo Masiza
  • Date: 2017
  • Subjects: Railroads - Maintenance and repair , Mechanical wear , Railroad engineering , Reliability (Engineering) , Electric railroads - Equipment and supplies - Management
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/262890 , uj:27786
  • Description: M.Tech. , Abstract: The wavelength fixing mechanism is studied by correlating natural frequencies of a locomotive wheelset to rail corrugation frequency. The bending natural frequencies of a locomotive wheelset are found to be related to a corrugation frequency at the Belfast to Steelpoort track. Modal analysis was conducted to determine the natural frequencies of the wheelset, and a corrugation frequency was calculated using captured train speeds and measured wavelengths. Due to severe curving forces, corrugation is only on curved track, particularly on the inner (low) rail of the track with wavelengths of 58 mm - 90 mm. Corrugation is understood to have occurred due to wear because there is no discernible metal flow on it at all curves. Concrete sleepers have an influence on the formation and sustaining of corrugation on rails - given the fact that corrugation was only found on curved track supported on concrete sleepers. There is a strong discernible relationship between corrugation wavelengths and train speeds; this is true especially for loaded trains. The train speeds are directly proportional to the wavelengths, whereas the tractive efforts are inversely proportional. This makes sense given the fact that in general, tractive efforts are inversely proportional to train speeds. Reference [1] states that amongst most researches that have been conducted over a century, an increase in corrugation wavelength with increasing train speed is observed. The greater the curve radius, the longer the wavelengths. In order to avoid long-pitch corrugation, the track curve radius should be reduced to less than 400 m, this means smaller radius curves have mostly short-pitch corrugation (wavelength < 80 mm) and large radius curves have mostly long-pitch (wavelength > 80 mm) [2]. There seems to be no discernible relationship between the track gauge deviation and the degree of severity of corrugation. All corrugated curves were found on curves with track gauge deviation, either narrowed or widened. Track curves with corrugation were compared with those that have no corrugation present. Track gauge deviations for curves with no corrugation are significantly less than those of curves with corrugation. This research study also looked at answering some of the common questions, regarding corrugation and its relationship with the environment and terrain.
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Digitalisation for optimisation of railway interlocking tests

  • Authors: Nzama, Sipho Ian Ntokozo
  • Date: 2019
  • Subjects: Railroads , Railroads - Safety measures , Reliability (Engineering) , Railroad engineering , Engineering systems - Testing
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/297348 , uj:32414
  • Description: M.Phil. (Engineering Management) , Abstract: Railway system interlocking testing is highly valued and it is a priority that requires stringent procedures which are guided by rail safety regulations. Historically, interlocking testing required significant protocols and efforts which resulted in expensive resource allocation in the form of personnel, equipment and time. The introduction of new technology can potentially reduce the configuration setup times and automate repetitive testing. This in turn can improve the reliability of the test results, save time and resources. This study highlights modernised technology that proposes a new automated system setup that could improve the testing process as this technology can potentially replace traditional testing methods. The findings of this study prove that; the use of digital technology in railway interlocking testing can significantly reduce the amount of time traditionally spent on this process, digital testing can increase the reliability of the test results and it can save on the required human resources to run the tests. A key additional benefit of the digital system is that it uses Siemens Computer Aided Signalling (SICAS), which is developed to comply with the Safety Integrity Level 4 (SIL4) of the European Committee for Electrotechnical Standardisation (CENELEC) Standard EN 50126 of Railway Applications.
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Factors affecting the reliability of motor coaches within Metrorail in the Gauteng Region

  • Authors: Makole, Sekhuthe James
  • Date: 2020
  • Subjects: Railroads - Maintenance and repair , Railroads - South Africa - Gauteng , Railroad engineering - South Africa - Gauteng , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/444977 , uj:38912
  • Description: Abstract: In most countries today, railway services form the backbone of the transport system. A passenger train’s service is one mode of transport that is widely used in most countries across the world. Over the past few years, PRASA, one of the passenger railway operators in South Africa has been experiencing a tremendous decline in performance of its rolling stock fleet. The direct impact of this decline in performance has led to a reduction in patronage, loss of revenue and poor company reputation. From the literature reviewed, there is less insufficient evidence regarding the challenges this organisation is facing. The purpose of this study was to explore the factors that affect the reliability of the fleet with the aim of assisting the organisation improving its fleet performance. The class 5M2A motor coaches operating in Gauteng region was used as the population of interest for this research... , M.Phil. (Engineering Management)
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Factors that can improve the reliability of the traction motor for the locomotives

  • Authors: Bopape, Thulare Kgaugelo
  • Date: 2018
  • Subjects: Locomotives , Railroads , Reliability (Engineering)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/393621 , uj:32574
  • Description: Abstract : In recent years, many customers are willing to pay product or service that will last them for a long time without disturbing their day to day run of business. Reliability management for the physical resources has to turn out to be the highly important aspect of running the business, especially in the logistics industry. It is vital for the customer to have a full understanding of the product lifecycle for the purpose of knowing the lifespan of a purchased product. Reliability development is directly linked to the product lifecycle cost (PLCC). Unreliability motor unit causes PLCC to increase and it is affecting the manufacturer’s revenue profits and their reputation. This study presents an approach of identifying factors that increase the reliability of traction motors and reduces its life cycle costs by quantifying the reliability of motor units in the rail environment, collecting data of failure statistics. This stats will be used to determine defect severity and how they affect the overall reliability of the system when components failed. The determination of the quantitative pilot survey was to examine the concept reliability management such as mean time between failures (MTBF), failure rate, projected PLCC for the duration of the warranty period for traction motor of Railway locomotives. Original Equipment Manufacturers are odd to investigate the potential means of dropping PLCC and improve the reliability of the product. Components such as brushes, commutator, brush rings, bearing and winding were identified as the main failures that occur frequently according to the stats collected at company X. Those components were scrutinized using reliability techniques such as Root Causes Analysis (RCA), Failure Mode and Effective Analysis (FMEA) and MTBF to determine the causes and effects of parts failing during their operational period. The risk was measured in the process. The Reliability was defined as the probability that the product or system performs its intended function in a specified time and environmental conditions at without changes its physical characteristics. Reliability can be expressed as the possibility of attainment. It is measured in terms of Mean Time between Failures (MTBF). The definition is broken down into three points which are as follows:  Probability–Consumers expect the probability to be 100 percent. “Useable”  Intended Function –Goods needs to be suitable to carry out its main activity without failing.  Stated Conditions –Goods should be able to withstand environmental conditions without error. The findings reveal that finite training for operators that assemble the motor unit takes places. The periodic inspection must be conducted to prevent failure from occurring. Customers should be included in the reliability management program to educate them on how to use the product efficiently without causing unnecessary faults. Find ways of identifying possible failure can save a lot of time and effort for both manufacturers and endusers. , M.Phil. (Engineering Management)
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Factors that cause engine failuire on diesel locomotives

  • Authors: Mayoyo, Aobakwe Reginald
  • Date: 2015
  • Subjects: Diesel locomotives - South Africa - Maintenance and repair , Diesel locomotives - South Africa - Reliability , Railroads - Dieselization - South Africa , Reliability (Engineering) , Transnet (Firm : South Africa)
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/213045 , uj:21071
  • Description: Abstract: The aim of the research is to find the factors that cause engine failures in diesel locomotives within Transnet. The research will focus on the diesel locomotives in the region of Thabazimbi and Pretoria. Diesel locomotives need to be in good working order for them to be able to haul goods for the growth of the economy. The company must deliver everything on time according to customer demand. The failures affect the company financially: they have to repair the engine, which costs about R1.2 million to rebuild, and a new engine costs R 3.2 million. Corrective actions play an important role in coal transportation. Reliable engineering and maintenance ensures that the product is always available. Reliability is known as the probability that an item or device can perform the required functions without failures for a specific period of time. Maintenance and reliability engineers should know all the techniques to solve engineering issues. The research shows that the company had the same problem as China and Ukraine. The failures were caused by maintenance that was not done properly on the diesel locomotive. The company has a maintenance strategy that they used on the diesel locomotive. It was found that the major cause of engine failures was using the wrong type of cylinders on the 39 200 class diesel locomotive. The 39 200 class uses millmille cylinders, not chrome cylinders. These cylinders differ from the usual material used to make cylinders. It was found that most artisans and the logistics department did not know which cylinders were supposed to be used on the 39 200 class diesel locomotive. The locomotives were newly built in South Africa, but not all the artisans, planners and trade hands were aware of the different cylinders used on the locomotive. The reliability and maintenance engineers, including the logistics department, have to work together in purchasing new material by making sure the specifications are clear to the supplier. The company had to do root cause analyses because they wanted to be competitive in the railway industry. The company should increase resources in the Thabazimbi depot to avoid locomotives having to be hauled to Koedoespoort owing to the insufficient number of artisans and trade hands they have at Thabazimbi. The workshop in Thabazimbi should do all the lifting work required on the locomotive, change radiators, change out compressors and change out cylinders. , M.Ing. (Engineering Management)
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Fuzzy logic and condition-based maintenance approaches to machine failure analysis

  • Authors: Mushiri, Tawanda
  • Date: 2017
  • Subjects: Fuzzy logic , Fuzzy systems - Industrial applications , System failures (Engineering) , Reliability (Engineering)
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/243068 , uj:25088
  • Description: D.Ing. (Engineering Management) , Abstract: When the complexity of the controller plant is a non-linear system, the production process cannot be fulfilled by the control effect and it is not easy to manipulate the parameters on Proportional-Integral-Derivative Controller. The major objective under study is simulating and modelling machinery then come up with a suitable intelligent Condition Based Maintenance system (i.e to develop a suitable intelligent system using fuzzy logic and artificial intelligence). The area under study of Fuzzy Logic came as a concern of nonlinear systems which fail to give correct information since machines use conventional Proportional-Integral-Derivative and hence this is for linear systems. Considering vibrations and continuous failure of machines, this will cause incorrect data portraying. Three companies were done in this thesis and all were analysed using fuzzy logic and some finite element analysis of components to monitor the parameters. Root cause analysis was also done to determine what was failing on different equipments. Three companies in a developing country were used as case studies for testing fuzzy logic approaches and models to machinery failure analysis. The three companies are designated as follows: Beverages Production Company, Hydro Power Generating Company and Water Distributing Company. The overall effectiveness of the companies were heavily affected due to many breakdowns. The main problem was found to be resulting from failure to monitor nonlinear systems that naturally exist in such environments. On the bottle washer at Beverages Production Company, fuzzy logic with Model Reference Adaptive Control to prevent failure on the bottle washer and introduce an intelligent Condition Based Maintenance program was done, a solution to come up with a control system that monitors water in the dam as well as protecting the equipment from failure and do stability control of machinery for Water Distributing Company as well as apply the concept of Maintenance Free Operating Period reliability metric to determine maintenance intervals as opposed to Mean Time Between Failure to the Hydro-Power Generation Company and also do a Simulink control on the governor. The results of the simulation of the control strategy of Fuzzy Logic Proportional-Integral-Derivative Controller have much preferred performance as compared to the general Proportional-Integral-Derivative Controller. This was done in the Simulink/Matlab simulation environment. The innovations behind this thesis at Beverages Production Company, the pneumatic valve of the bottle washer which controls the discharge of clean bottles was occasionally sticking or failing resulting in significant loss of production in the plant since all the other processes which follow depend on the bottle washer. The main causes of failure were caused by poor control of temperature and pressure. Excessive moisture and abrasive particles also caused failures. In order to solve this problem a Model Reference Adaptive Fuzzy Controller was designed for the pneumatic valve using the Matlab software. The error resulting from the difference between the actual system output and that of the reference model was executed by the Fuzzy Logic Controller. At company Hydro-Power Generation Company, the administering system of a 150 Megawatts Francis Turbine was developed using fuzzy logic. The representative framework parameters were mirrored with the real information accessible in the power plant. At Water Distributing Company the problem of corroding gates and failure was solved using solid works, Matlab, Programmable Logic Controller and Simulink. The sluice gate valve was controlled and done stability by Matlab to avoid failure. After fuzzy logic is applied in each and every company under study, the breakdowns will be less and machinery can be diagnosed and prognosis is easy to foresee the failures. A new gate was designed by the researcher. The research has shown that fuzzy logic being intelligent, machinery can last longer and production is high. The limitations are that although it is good in monitoring but in some machinery and companies may not work well because of environment like in the water gates. It is also expensive to implement and difficult to convince management to do the research for a start.
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Improving the reliability of 3kV DC traction substations

  • Authors: Sprong, Willem
  • Date: 2008-07-18T13:41:02Z
  • Subjects: Reliability (Engineering) , Electrical railroads , Electrical substations
  • Type: Thesis
  • Identifier: uj:7329 , http://hdl.handle.net/10210/806
  • Description: This dissertation deals with the important issue of reliability management for 3kV DC Traction Substations. A general introduction explaining the changes that took place in the railway environment is followed by a description of the system. Understanding the components of the system is important but care must be taken not to go into too much detail. The level at which the system is broken down will be sufficient for this study. Some relevant reliability theory is discussed and applied to the 3kV DC system. An analysis of the failure modes and criticality helps to identify the components that need special focus during the inspections. With a good understanding of the above aspects a process for the inspection of substations is formulated. To design a process that can be used throughout an organisation, certain test must be done. The tests include determining the influence of expertise and experience of the person carrying out the inspections. The result of this study is an inspection process for 3kV DC traction substations that can be used to obtain a good idea of the condition of the system in order to make maintenance decisions that will improve the reliability of the system. , Prof. J.H.C. Pretorius Prof. W.A. Cronje
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Improving the reliability of a chemical process plant

  • Authors: Tomo, Zonwabele Zweli Simon
  • Date: 2012-06-05
  • Subjects: Reliability (Engineering) , Plant maintenance - Management , Chemical plants - Equipment and supplies , SASOL WAX , Engineering instruments , Chemical engineering - Safety measures
  • Type: Thesis
  • Identifier: uj:2427 , http://hdl.handle.net/10210/4887
  • Description: M.Phil. , In modern society, professional engineers, technologists and technical managers are responsible for the planning, design, manufacture, maintenance and operation of the processes and systems ranging from simple processes to complex systems. The failure of these can often cause effects that range from inconvenience and irritation to severe impact on the society and its environment. Users, customers and society in general expect that products be reliable and safe at all times (Allan & Ballinton 1992). The biggest investment in any plant is, arguably, on individual plant equipment. It is therefore reasonable to give the greatest attention possible to the health and integrity of equipment that form part of the chemical process plant.Most of plant failures occur without warning and this result in equipment breakdowns, huge production losses and expensive maintenance. The reaction to plant failures has, in most cases, been a reactive maintenance which means that the plant equipment must fail before the cause of fault is investigated and the equipment is repaired. Reactive maintenance has shortcomings in that it is successful in solving problems temporarily but does not guarantee prevention of fault recurrence. Equipment and process failures waste money on unreliability problems. The question that arises is. ‘How reliable and safe is the plant during its operating life?’ This question can be answered, in part, by the use of quantitative reliability evaluation. The growing need to achieve high availability for large integrated chemical process systems demands higher levels of reliability at the operational stage. Reliability is the probability of equipment or processes to function without failure when operated correctly for a given interval of time under stated conditions. This research dissertation is aimed at developing equipment optimisation program for the chemical process plant by introducing a logical approach to managing the maintenance of plant equipment. Some relevant reliability theory is discussed and applied to the Short – Path Distillation (SPD) plant of SASOL WAX. An analysis of the failure modes and criticality helps to identify plant equipment that needs special focus during inspection.
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Management of the diagnosis, specification and execution of concrete repairs for reliability

  • Authors: Bester, Johannes Jacob
  • Date: 2011-02-28T06:08:29Z
  • Subjects: Concrete maintenance and repair , Reliability (Engineering) , Maintainability (Engineering) , System failures (Engineering)
  • Type: Thesis
  • Identifier: uj:7034 , http://hdl.handle.net/10210/3556
  • Description: M. Phil. , Concrete is worldwide the most commonly used construction material and, although concrete is durable when exposed to aggressive conditions, it requires some maintenance. If this maintenance is neglected for a prolonged period of time, intrinsic and extrinsic factors will cause the concrete to degrade necessitating repair and rehabilitation. The correct diagnosis of the root cause of degradation, proper specification of repair materials and quality execution of the concrete repairs all contribute to the reliability of the repairs. The correct management of the repair process is necessary to ensure reliability in order for the structure to be returned to an acceptable state.
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Optimisation of mechanised maintenance management of railway track infrastructure

  • Authors: Zaayman, Leon
  • Date: 2017
  • Subjects: Railroad tracks - Maintenance and repair , Railroads - Management , Reliability (Engineering) , Railroad engineering
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/285908 , uj:30928
  • Description: Abstract: Railway track infrastructure is a complex system consisting of various subsystems which require incremental maintenance from all engineering disciplines; all of whom are competing for the limited time and number of available maintenance windows. The constant demand for higher traffic volumes, increased train speeds and heavier axle loadings all result in an exponential increase in maintenance requirements but the time available for maintenance is as a result even further reduced. This requires a more scientific lifecycle approach to infrastructure maintenance management. It also requires increased performance from mechanised construction, maintenance and renewal machines to keep the infrastructure reliable, available, maintainable, affordable and safe within the short windows. The objectives of this thesis are to address the optimisation of infrastructure maintenance management and to provide a model with selection criteria for maintenance machinery and their features for the prevailing circumstances. , D.Phil. (Engineering Management)
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