Doctoral Degrees (Mechanical Engineering)

Permanent URI for this collectionhttps://hdl.handle.net/10413/6861

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Contractible arms elevating search and rescue (Caesar) robot : improvements and modifications for urban search and rescue (Usar) robots.
(2010) Stopforth, Riaan.; Bright, Glen.; Harley, Ronald G.
Rescuers have lost their lives in events requiring them to go into dangerous areas that have unstable structures and gases. Robots are necessary for search and rescue purposes, to access concealed places and environments to which fire fighters and rescue personnel cannot gain entry. Robots that were previously used encountered problems with communication, chassis design, traction and sensory systems. Improvements are required for the successful localization of victims. Research on improvements in these areas were carried out for the use in the CAESAR (Contractible Arms Elevating Search And Rescue) robot. Contributions were made in the area of Urban Search And Rescue (USAR) robots focusing on antenna design, communication protocols, chassis design, traction system and artificial intelligence on decisions relating to gas danger levels for humans and the robot. The capabilities of CAESAR is audio, video and data communication irrespective of the orientation of the robot and the antennas. Penetration of radio frequencies through building material is possible. Reliable data communication is achieved with the designed Robotics Communication Protocol (RCP). The chassis is designed to have traction on unstable terrain and autonomously transform flipper arms for the best orientation. Materials for the body were selected and constructed to be able to withstand the unstable environments and high temperatures which they will encounter. The control station display gives the rescuers immediate indication of the gas concentrations detected by the on-board gas sensors. Developed analytical models determine the danger of the gas concentrations for victims, rescuers and the robots.
Design and testing of a composite material for modelling wind turbine blade structures in tropical region.
(2018) Tefera, Getahun Akulu.; Adali, Sarp.; Bright, Glen.; Davidson, Innocent Ewean.
Currently large wind turbine blades have been installed in several offshore and onshore wind farms around the world, particularly in the desert areas of North East Africa where wind turbine blades and nacelles are affected by elevated temperatures. The aim of this study is to investigate the effect of temperature variation on the mechanical behaviour of composite wind turbine blades installed in tropical wind farms. The blades are constructed from unidirectional carbon fibre/epoxy, glass fibre/epoxy and hybrids of these two composite materials. ASTM standards were taken into account when the composite specimens were manufactured for testing purposes. Short Beam Shear (SBS), Dynamic Mechanical Analysis (DMA) and tensile tests were conducted under increasing temperatures to investigate the mechanical behaviour of composite materials when used for structural modelling of wind turbine blades. Experimental findings revealed that the strength and stiffness properties of composite specimens were reduced when temperatures increased. Betz’s element momentum theory and Glauert’s modelling methods were used to investigate the characteristics of composite wind turbine blades measuring 54m and generating 2MW power. Flap-wise loading was taken into account along the length of the wind turbine blades when they were analysed using the Blade Element Momentum (BEM) theory. The wind turbine blades were developed using carbon fibre/epoxy, glass fibre/epoxy, glass-carbon fibre/epoxy and carbon-glass fibre/epoxy composite materials. The tip deflection of the blades was analysed allowing for different flap-wise and thermal loadings. Simulation results indicated that a glass/epoxy blade has the highest and a carbon/epoxy blade the lowest tip deflection. The values for the tip deflections of the blades show minimal change under thermal loading. To study the mechanical behaviour of the blades under thermal loading, an element-wise approach was developed and the failure index for different composite materials was computed. Tsai-Wu failure criterion was employed to determine the failure index of each composite material under thermal and mechanical loadings. Blades failed when the thermal loading was above 40ºC irrespective of the flap-wise loading. This finding was similar to the experimental results mentioned above. Carbon/epoxy showed non-linear behaviour when the test temperature approached 40ºC. Generally, experimental and numerical results are comparable and can be considered valid. To conclude carbon-glass fibre/epoxy composite wind turbine blades are observed to be a better option for tropical wind farms based on experimental and simulation results. Iqoqa Njengamanje sekufakwe ophephela bomoya abakhulu emapulazini amaningi omoya asolwandle nasezweni emhlabeni jikelele, ikakhulukazi ezindaweni eziwugwadule zaseMpumalangantshonalanga Afrika lapho amazinga okushisa aphakeme enomthelela kophephela bomoya nakuzembozo zezihambisiphephela. Inhloso yalolu cwaningo ngukuhlola umthelela wokuguquguquka kwamazinga okushisa endleleni okusebenza ngayo ophephela bomoya abafakwe emapulazini asezindaweni ezishisa kakhulu. Ophephela bakhiwe ngomabhekanxazonke befayibha yekhabhoni/ ephoksi, ifayibha yengilazi/ephoksi, Kucatshangelwe amazinga e-ASTM ngenkathi kwakhiwa amasampula ayindidiyela ngenhloso yokuhlola. Kwenziwe uhlelo lwe-Short Beam Shear (SBS), Dynamic Mechanical Analysis (DMA) nokuhlola kwamathensayili ngaphansi kwamazinga okushisa anyukayo, ukuhlola indlela ezisebenza ngayo izakhi eziyindidiyela uma zisetshenziselwa ukubona ukuthi singama kanjani isakhiwo sophephela bomoya. Imiphumela yokuhlola iveze ukuthi amazinga amandla nokuqina kwamasampula ayindidiyela kwehlile uma kunyuswa amazinga okushisa. Kusetshenziswe injulalwazi ka-Betz yomthamosivinini kanye nezindlela zika-Glauret zesibonelokulinga ukuhlola izimpawu zophephela bomoya abayindidiyela, abanesikalo esingu-54m futhi esiphehla amandla angu-2MW. Kucatshangelwe isisindo sokuthwala uma ophephela bebheke phansi noma phezulu ngokunjalo nobude bophephela bomoya ngenkathi behlaziywa, kusetshenziswa injulalalwazi i-Blade Element Momentum (BEM). Ophephela bomoya benziwe kusetshenziswa izakhi eziyindidiyela zefayibha yekhabhoni/ ephoksi, ifayibha yengilazi/ ephoksi nefayibha yekhabhoni-ngilazi/ ephoksi. Impebezo yezihloko zophephela ihlaziywe kuvunyelwa okuhlukahlukene kwesisindo sokuthwala netemali, uma ophephela bebheke phansi noma phezulu. Imiphumela yokulingisa ikhombise ukuthi uphephela wengilazi/ ephoksi unempebezo yesihloko ephakene kanti uphephela wekhabhoni/ ephoksi unempebezo yesihloko ephansi. Amavelu empebezo yezihloko zophephela akhombisa uguquko olusesilinganisweni esincane, ngaphansi kokulayishwa kwetemali. Ukucwaninga okwenziwa ngophephela okuphathelene nokusebenza kwemishini uma kulayishwe itemali, kwenziwe ngokuqamba indlela evuna i-elementi, kwase kwenziwa uhlelo lokubala ngekhompyutha inkomba kwehluleka yezakhi eziyindidiyela ezihlukahlukene. Kuthathwe indlelakukhetha kuhluleka kaTsai-Wu ukubona inkomba kuhluleka yesakhi ngasinye esiyindidiyela uma kulayishwe itemali nokusebenza ngemishini. Ophephela behlulekile uma umthamo wetemali ungaphezu kuka-40ºC kungakhathaliseki izinga kulayisha elivuna ukubheka phansi noma phezulu kophephela. Okutholakele bekufana nemiphumela yokuhlola ebalulwe ngenhla. Ikhabhoni/ ephoksi ikhombise indlela okwenza ngayo ophephela engaqondile uma amazinga okushisa okuhlola esondela ku-40ºC. Ezimweni eziningi, imiphumela yokulinga neyezibalo iyaqhathaniseka futhi ingase ibhekwe njengekholakalayo. Ukuphetha, ophephela bomoya abayindidiyela yefayibha yekhabhoningilazi/ ephoksi babonakala beyisu elingalunga kahle emapulazini omoya uma kuthathelwa emiphumeleni yokuhlola nokufanisa.
Design, modelling and simulation of 2 novel 6 DOF hybrid machines.
(2012) Shaik, Ahmed Asif.; Bright, Glen.
Industrial robot arms are an essential part of automated manufacturing, and perform tasks such as component assembly, welding, light machining, spray painting, etc. They are highly repeatable, can be calibrated to be sufficiently accurate and they eliminate human error. The serial robot architecture is by far the most ubiquitous in modern day manufacturing, as the technology is highly refined in its current state; the machine architecture provides great dexterity and it has a large useful workspace. This architecture however does have some problems, one of which is a large machine moving mass. The primary reason for this lies in the location of its motors and gearboxes. Due to the robot's significant inertia it utilizes a large amount of energy. This thesis focused on the mechanical design, mathematical modelling and simulation of 2 robotic arm designs which had a hybrid nature. They were classified as hybrid due to the fact that their architectures departed from both the classic definitions of serial kinematics manipulators/machines (SKMs) and parallel kinematics manipulators/machines (PKMs). The primary design goal was to merge some of the advantages of both architectures, i.e. a large workspace to footprint ratio and high end-effector dexterity which was found in serial robots, combined with the low inertia of a parallel robot for improved dynamics. Serial and parallel robots were complementary, and these design goals could not co-exist in a single purist robot architecture. The designs had a full complement of 6 DOFs (degrees of freedom), 3 DOFs for spatial position of the wrist and 3 DOFs for orientation of that wrist. They also had a lower machine moving mass, a fact that was thought to improve speed and energy usage. A major contribution of this research PhD project was a comparative energy usage study, which was performed against the serial robot as a measure. This was done for both hybrid designs as well as another model which represented 2 existing patented designs. The purpose of that was to determine if lowering the machine moving mass would improve energy efficiency, and to determine which design was best.
Development of a decision support system for decision-based part/fixture assignment and fixture flow control = Ukusungulwa kohlelo lokuxhaswa kwezinqumo mayelana nokwabiwa kwezingxenye ezakhiwayo kanye nokuhanjiswa kwazo.
(2018) Kasie, Fentahun Moges.; Bright, Glen.; Walker, Anthony John.
ABSTRACT: An intense competition in a dynamic situation has increased the requirements that must be considered in the current manufacturing systems. Among those factors, fixtures are one of the major problematic components. The cost of fixture design and manufacture contributes to 10-20% of production costs. Manufacturing firms usually use traditional methods for part/fixture assignment works. These methods are highly resource consuming and cumbersome to enumerate the available fixtures and stabilise the number of fixtures required in a system. The aim of this study was to research and develop a Decision Support System (DSS), which was useful to perform a decision-based part/fixture assignment and fixture flow control during planned production periods. The DSS was designed to assist its users to reuse/adapt the retrieved fixtures or manufacture new fixtures depending upon the state of the retrieved fixtures and the similarities between the current and retrieved cases. This DSS combined Case-Based Reasoning (CBR), fuzzy set theory, the Analytic Hierarchy Process (AHP) and Discrete-Event Simulation (DES) techniques. The Artificial Intelligence (AI) component of the DSS immensely used a fuzzy CBR system combined with the fuzzy AHP and guiding rules from general domain knowledge. The fuzzy CBR was used to represent the uncertain and imprecise values of case attributes. The fuzzy AHP was applied to elicit domain knowledge from experts to prioritise case attributes. New part orders and training samples were represented as new and prior cases respectively using an Object-Oriented (OO) method for case retrieval and decision proposal. Popular fuzzy ranking and similarity measuring approaches were utilised in the case retrieval process. A DES model was implemented to analyse the performances of the proposed solutions by the fuzzy CBR subsystem. Three scenarios were generated by this subsystem as solution alternatives that were the proposed numbers of fixtures. The performances of these scenarios were evaluated using the DES model and the best alternative was identified. The novelty of this study employed the combination of fuzzy CBR and DES methods since such kinds of combinations have not been addressed yet. A numerical example was illustrated to present the soundness of the proposed methodological approach. Keywords: Decision support systems, case-based reasoning, analytic hierarchy process, fuzzy set theory, object-oriented methods, discrete-event simulation, fixtures. IQOQA LOCWANINGO : Ukuncintisana okunezinhlelo eziguquguqukayo kulesi sikhathi samanje sekwenze ukuthi kube nezidingo ezintsha ezinhlelweni zokukhiqiza. Phakathi kwakho konke lokhu izingxenye (fixtures) zingezinye zezinto ezidala izinkinga. Intengo yokwakha uhlaka lwengxenye kanye nokuyikhiqiza kubiza amaphesenti ayi-10 kuya kwangama-20 entengo yokukhiqiza. Amafemu akhiqizayo avamise ukusebenzisa izindlela ezindala zomsebenzi wokwaba izingxenye. Lezi zindlela zidla kakhulu izinsizangqangi futhi kuthatha isikhathi eside ukubala izingxenye ezikhona nokuqinisekisa ukuthi kunesibalo esanele kulokho okumele kube yikho ohlelweni lokusebenza. Inhloso yalolu cwaningo bekungukucwaninga nokusungula i-Decision Support System (DSS) ebe lusizo ekwenzeni umsebenzi wokuthatha izinqumo ngokwabiwa kwezingxenye kanye nokuhanjiswa kwazo ngezikhathi ezimiselwe ukukhiqiza. I-DSS yakhelwa ukusiza labo abayisebenzisayo ukuze basebenzise noma bazisebenzise lapho zingakaze zisetshenziswe khona lezo zingxenye ezibuyisiwe, noma kwakhiwe ezintsha kuya ngokuthi zibuyiswe zinjani lezi ezibuyisiwe nokuthi ziyafana yini nalezo ezintsha. I-DSS isebenzise amasu ahlanganise i-Case-Based Reasoning (CBR), injulalwazi echazwa ngokuthi i-fuzzy, ne-Analytic Hierarchy Process (AHP) ne-Discrete-Event Simulation (DES). I-Artificial Intelligence (AI) eyingxenye ye-DSS isebenzise kakhulu uhlelo lwe-fuzzy CBR luhlangene ne-fuzzy AHP kulandelwa imithetho yolwazi olumayelana nohlobo lomsebenzi. I-CBR isetshenziswe ukumelela lezo zimo zamanani ezingaqondakali nezingaphelele kulezo zingxenye. I-AHP e-fuzzy yasetshenziswa ukuze kutholakale ulwazi kochwepheshe olubeka phambili lezo zingxenye. Ama-oda ezingxenye ezintsha kanye namasampuli asetshenziselwa ukuqeqesha avezwe njengamasha kanye nabekade evele ekhona ngokulandelana kusetshenziswa indlela eyaziwa ngokuthi yi-Object-Oriented (OO) method lapho kubuyiswa izinto noma kunezinqumo eziphakanyiswayo. Izindlela ezijwayelekile zokulandelanisa nokufanisa zisetshenziswe ohlelweni lokubuyisa izinto. Kusetshenziswe isu eliyi-DES ukuhlaziya ukusebenza kwezisombululo eziphakanyiswe yindlela ye-CBR e-fuzzy. Le ndlela iphinde yaveza izimo ezintathu eziphakanyiswe ukuba zibe yisisombululo esibalweni sezingxenye ezihlongozwayo. Ukusebenza kwalezi zimo kuhlungwe ngokusebenzisa indlela ye-DES kwase kuvela inqubo engcono. Ukungajwayeleki kwalolu cwaningo kusebenzise ingxube yezindlela ze-fuzzy CBR ne-DES ngoba lolu hlobo lwengxube belungakaze lusetshenziswe. Kusetshenziswe isibonelo sezibalo ekwethuleni ukusebenza kwale nqubo yokusebenza ehlongozwayo.
The development of methods for the design and evolution of reconfigurable cellular manufacturing systems.
(2016) Padayachee, Jared.; Bright, Glen.
The concept of reconfigurable manufacturing is presently being researched due to the need for production systems that are able to economically respond to changes in markets and the rapid introduction of new products. Cellular Manufacturing Systems (CMS) are a central concept in just-in-time and lean manufacturing. Although CMS are able to provide a strategic operating advantage, machine cell clusters do not remain optimal over an extended period of time. The concept of a Dynamic CMS (DCMS) has received attention in recent years; a DCMS is a system where the layout of machines change in order to improve the responsiveness of CMS to changing production requirements. A deficiency in existing DCMS methods is that reconfiguration plans are generated without the consideration of an initial design of the factory floor space for future change. This research distinguishes Reconfigurable CMS (RCMS) from DCMS, as a system that is designed at the outset for changes to system layout and cell configurations. The concept of a Factory Configuration Template (FCT) is proposed in this research; the FCT is a design of the factory floor space to ensure the feasible implementation of reconfiguration plans generated by mathematical models. A nine step method for FCT design is presented that uses a Simultaneous Fuzzy Clustering Heuristic to develop manufacturing cells and part families. A Tabu Search algorithm was develop to generate the optimal arrangement of machine sites in cells. Three multi-period machine assignment models were developed that determine reconfiguration plans based on changing product demand and the introduction of new products. The models that were developed included two integer linear programs that determine the distribution of machine resources among cells over multiple periods. A quadratic zero-one programming model was developed that distributes machines among available sites in cells to promote unidirectional part flow. The results show that RCMS is able to provide a more economical solution than traditional CMS with the added advantage of improved part flow in the system.
Distributed control synthesis for manufacturing systems using customers' decision behaviour for mass customisation.
(2013) Walker, Anthony John.; Bright, Glen.
The mass customisation manufacturing (MCM) paradigm has created a problem in manufacturing control implementation, as each individual customer has the potential to disrupt the operations of production. The aim of this study was to characterise the manufacturing effects of customers’ decisions in product configuration, in order to research steady state control requirements and work-in-process distributions for effective MCM operations. A research method involving both analytic and empirical reasoning was used in characterising the distributed control environment of manufacturing systems involved in MCM. Sequences of job arrivals into each manufacturing system, due to customers’ decisions in product configuration, were analysed as Bernoulli processes. A customer model based on this analysis captured the correlation in product configuration decisions over time. Closed form analytic models were developed from first principles, which described the steady state behaviour of flow controlled manufacturing systems under generalised clearing policy and uncorrelated job arrival sequences. Empirical analysis of data sets achieved through discrete event simulation was used in adjusting the models to account for more complex cases involving multiple job types and varying correlation. Characteristic response surfaces were shown to exist over the domains of manufacturing system load and job arrival sequence correlation. A novel manufacturing flow control method, termed biased minimum feedback (BMF) was developed. BMF was shown to posses the capability to distribute work-in-process within the entire manufacturing facility through work-in-process regulation at each manufacturing system, so as to increase the performance of downstream assembly stations fed from parallel upstream processing stations. A case study in the production of a configurable product was used in presenting an application for the models and methods developed during this research. The models were shown to be useful in predicting steady state control requirements to increase manufacturing performance.
EEG artefact identification and extraction in autonomic wireless network for future coordination and control of semi-autonomous systems.
(2015) Onunka, Chiemela.; Bright, Glen.
Electroencephalographic signals is used to show correlations between specific forms of cognitive activities and robotic hand motion. This research presents EEG artefact identification, extraction and classification for use in the development of a robotic hand. The findings from the study were used to control a robotic arm and develop a suitable communication network that has no dependence on the human nervous system communication pathways. The research was focused at modelling bio-sensing and bio-monitoring feedback system using electroencephalographic (EEG) as the source signal. An EEG communication system was developed for implementation on the robotic hand developed by the Mechatronics and Robotics Research Group (MR2G). Neuronal activities produce electrical signals on surface of scalp in human beings. EEG the raw material for robot command development was generated from the neuronal activities. Specific techniques were used in modelling the EEG analysis system for implementation on the robotic hand. The techniques used include the Radial Basis Function (RBF) neural network, Linear Discriminant Analysis (LDA), Principal Component Analysis (PCA), Singular Value Decomposition (SVD), Wavelet Packet Transform (WPT), Multilayer Perceptron Neural Network (MLPNN), Learning Vector Quantization (LVQ) neural network, Bayesian and probabilistic paradigms in developing the EEG artefact identification, extraction and classification model. These techniques were investigated and implemented in order to have an efficient EEG artefact identification and extraction system for controlling the robotic hand. The main contribution of the research was the identification, extraction and classification of electroencephalographic (EEG) artefacts in controlling a robotic hand. The specific contribution made in the research included the development of augmented EEG signal and EEG artefact extraction process using mathematical models. The models were used to develop integrated coordination and control architecture for the robotic arm. The research also made significant contribution to the development of modular Brain-Computer Interface (BCI) communication network. The BCI was augmented in autonomic wireless neural network activated by various EEG artefacts. The robotic hand control command codes were developed and they were modular in their application strategy. This was consolidated with adequate software and hardware architecture which were reconfigurable and leveraged using neuro-symbolic behaviour language in controlling the robotic hand developed by the Mechatronic and Robotic Research Group (MR2G).
The impact of disruptive technology on the manufacturing process, and productivity, in an advanced manufacturing environment.
(2022) Salawu, Ganiyat Abiodun.; Bright, Glen.; Onunka, Chiemela.
Disruptive technology plays a critical role in the performance of mechatronic systems in an advanced manufacturing environment. Robots were used to perform pick and place task in a virtual manufacturing environment. Newton-Raphson model, renewal theorem and queuing theory were used to model the disruptive technology and develop decision-making algorithms in an advanced process. The motion of the conveyor belt system starved modeled and simulated to determine suitable design parameters that were compatible with the tasks of the pick and place robot. MATLAB and Engineering Equation Solver (EES) were used to determine static solutions and simulated solutions to the pick and place problem in the advanced manufacturing process. The results from the simulations were used to develop suitable task-dependent operational conditions in the advanced manufacturing environment. The simulation results were used to determine the optimal conveyor speeds required for the robotic tasks. Comparing the throughput rate of the developed system with the simulated system indicated that optimal productivity was achieved when the decision-making algorithms were implemented at the early stages of the manufacturing process.
Manufacturing planning and operations optimisation for mass customisation manufacturing using computational intelligence.
(2015) Butler, Louwrens Johannes.; Bright, Glen.
This study determined whether an Advanced Manufacturing System could be optimised, more effectively than by traditional methods, using new and novel computational intelligence techniques. An Advanced Manufacturing System can be described as highly automated and highly complex systems that strive for global competitiveness. In the context of this study, these systems aim to compete in a Mass Customisation Manufacturing market. Traditional optimisation methods refer to methods based on mathematical models, experience, or industry best practice. Computational Intelligence refers to computational methods inspired by natural systems and processes. This includes, but is not limited to, evolutionary intelligence, Artificial Neural Networks, swarm intelligence, and fuzzy systems. This study investigated the optimisation of the manufacturing system from both a planning and an operations perspective. Research was carried out to identify Computational Intelligence paradigms and algorithms for Advanced Manufacturing System planning and operations optimisation. Static and dynamic simulation models of an Advanced Manufacturing System, for the respective perspectives, have been developed in order to simulate a manufacturing system designed to produce a hypothetical range of customisable men’s wristwatches on a mass scale at a competitive cost. A new Biogeography-Based Optimisation algorithm was developed to optimise an aggregate production plan using static simulation models. This algorithm was implemented to find the lowest production cost for the wristwatch production system case study. This algorithm produced a lower cost plan than a Simulated Annealing algorithm with a lower impact on workforce. A new Distributed Dynamic Selection Rule Strategy was developed for optimising production scheduling using dynamic simulation models. This new strategy was inspired by the Harmony Search principle and was based on traditional selection rules for scheduling. This strategy was able to produce statistically significantly lower average order lead times than three out of four traditional selection rules tested.
Trip steels as smart sensor alloys.
(2013) Bemont, Clinton Pierre.; Bright, Glen.; Cornish, Lesley.
Upon deformation, TRIP steels undergo progressive irreversible transformation from paramagnetic austenite to more thermodynamically stable, ferromagnetic αʹ-martensite. The change in magnetic permeability is readily detectable, and since TRIP steels also have excellent mechanical properties, this presents the opportunity for implementing cheap, robust structural health monitoring systems. However, the extent of martensitic transformation in TRIP steels is affected not only by the degree of deformation, but by environmental temperature at the time of deformation and strain rate. This creates inherent inaccuracy when implementing TRIP steels as sensor materials. In this thesis it has been demonstrated that it is possible to design TRIP steels that are less susceptible to these factors, show good deformation induced transformation, and can function simultaneously as sensors and structural elements. As-cast alloys were tested in compression, while annealed, hot-rolled and warm-rolled alloys were tested primarily in tension. There was considerable variation between alloys in rate of transformation with deformation. Martensitic transformation was evaluated magnetically and correlated with optical and scanning electron microscopy and X-ray diffraction results. Changes in magnetisation and magnetic permeability curves with deformation were characterised to ensure optimal electronic monitoring. Equations from literature for determining characteristic transformation temperatures, Ms and Md30 were evaluated experimentally for the alloy range of interest, and the best equations were selected to aid in the design of high alloy TRIP steels exhibiting strong transformation and low temperature sensitivity. Temperature sensitivity between alloys was found to vary as predicted. Temperature sensitivity was also compared in annealed, hot rolled and warm rolled conditions; the annealed condition showed the lowest sensitivity, and this is thought to be related to lower dislocation densities. Mining was targeted as a primary industry for application of these sensor systems because of the pressing need for greater safety and more efficient structural support at low cost. Two distinct devices for monitoring the structural health of mines were designed, built and tested, and a third was developed for the aerospace industry. Better understanding and control of the temperature sensitivity of martensitic transformation in TRIP steels is expected to aid not only structural health monitoring, but also the application of such materials to other areas of technology, such as sheet forming and high impact resistance applications. Although there are limitations on the extent to which TRIP steel transformation characteristics can be controlled, it was shown that they can be manipulated to enable successful implementation of new alloys for smart load or damage sensors. Practical, robust, low cost structural health monitoring sensors based on the smart properties of TRIP steels were shown to be feasible.

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Browsing Doctoral Degrees (Mechanical Engineering) by Author "Bright, Glen."