Browsing by Author "Brighton, James L."
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Item Open Access Assess the design of lorries and quarries for aggregates transport. Report to the Minerals Industry research Organisation(2010-05-05T00:00:00Z) Brighton, James L.; Richards, Terence E.The majority of aggregates extracted in the UK are transported from the quarry to the point of sale by construction trucks of either rigid chassis or articulated vehicle design. These vehicles have a unique set of requirements for haulage logistics as many of them must be capable of driving on unmade surfaces and constructed dirt roads not only within the quarry but more importantly at the goods destination. Such vehicles have to balance the on-road requirements of minimum energy consumption, low capital cost, low maintenance and low noise with the off road requirements of maintaining overall mobility whilst minimising their impact on the environment. This project investigates the environmental impacts of these vehicles and evaluates their design and use from an environmental perspective to establish whether changes to vehicle design or the layout of the quarries could lessen the impacts. The project considered current practices used for aggregate transport by road including operational methods vehicle choice and logistics. A structured survey technique was used to gather data from quarries producing sand and gravel, limestone and igneous metamorphic rock, located throughout the UK. The predominant findings were: 85% of road going aggregate transport trucks were required to travel on unsealed surfaces within the quarry. Trucks may be required to travel on unsealed surfaces at the point of delivery. 7% of the quarries surveyed had no means of cleaning debris from trucks before they left the quarry. All quarries covered loads when travelling on the highway.The major environmental impacts were: Aggregate transport trucks generate a significant amount of noise especially when unladen. Aggregate transport trucks can contaminate the public highway, with quarry and/or delivery point acquired debris, both near to, and at some distance from the quarry depending on prevailing weather conditions. To corroborate these findings using the general public's perspective, a small public survey was conducted using a face to face structured interview technique in three villages near to quarry operations. The results of this survey confirmed that noise from unladen trucks and debris deposited on the highway were the most significant impacts. To further investigate these issues an experiment was conducted to determine how the noise level from construction trucks compared to other road vehicles on the public highway. The results highlight the potential for empty trucks to generate significantly high impulse noise when travelling over uneven surfaces including potholes, manhole covers and drains. The predominant source of this noise is from the relative movement between the body and chassis. To control this movement the design of body damping systems should be investigated as a low cost solution. The major source of material transfer into the environment was via the trucks tyres. Experimental results showed that halving the tyre's recommended inflation pressure had a significant effect on the material collected within the tyre tread on a sandy loam soil. However, the relationship between soil-tyre adhesion, axle load and the soil's initial bulk density remains unclear and requires a further detailed investigation. A chassis sheeting/enclosure system has been suggested as a low cost method of preventing material being transferred to the chassis which would otherwise fall off on the road. Considering the design of construction trucks three areas were investigated namely; the tyre choice and use, the drive train and the body design along with the vehicles use within the quarry. Tyre choice is predominantly dictated by the aggregate's destination, which is often off-road and hence an off road biased tyre is chosen. Although in reality the majority of sites will not challenge the vehicles mobility, for those that might, the risk of getting a vehicle stuck was too great to justify the use of a more road biased tyre. However, the results from a tread cleaning experiment showed that inflation pressure could be used to reduce tread clogging. It is well reported in the literature that manipulating inflation pressure can improve the tractive capability of a tyre and maintaining the correct road inflation pressure can contribute to reduced fuel consumption. Central tyre inflation systems that are commercially available, allow inflation pressure to be controlled and monitored, however, further research is required to determine the optimum tyre pressure to be used for a given set of operating conditions. Alternative methods of powering truck ancillary equipment, including load bed tipping, have been investigated to reduce the need to run the engine at high speed under low load when tipping the body. A kinetic energy recovery system has the potential to reduce the overall environmental impact of the transport operation by reducing fuel use and engine emissions, and this could be employed to power auxiliary systems, but would be far better utilised to assist with vehicle propulsion during the drive cycle. Considering quarry design three options were highlighted that reduce the environmental impact of road going trucks: 1. Upgrade roads within quarries to enable low rolling resistance on-road tyres to be used on road going trucks without sacrificing mobility. 2. Adopt a demountable body system 3. Employ a flexible conveyor system from excavation face to quarry exitEach option reduces the distance a truck must move within the quarry on un-sealed surfaces. The use of a demountable system would permit a clear segregation between on-road and off road vehicle use within the quarry, but the practical issues associated with the system such as reduced payload and container storage would prevent its widespread adoption where off road capability remains a requirement at the delivery point. The ultimate solution could be considered to be a flexible conveyor system, and low carbon goods transit thereafter. This could be achieved by an advance in conveyor design to allow it to follow the excavator's movements, and transfer the material to the edge of the quarry for onward movement by low carbon transport.Item Open Access Design of a novel punch planter capable of producing equidistant seed spacing of irregular shaped seeds(2002-09) De Resende, Ricardo Capucio; Brighton, James L.Plants uniformly spaced in the field have a more efficient use of resources, due to their even distribution. There are also a better ability to compete against weeds, less spread of disease and lodging. Consequently the yield should be improved. Precise seed placement and seed location in the field are important for the management of the crop at a plant-scale level, for such operations as mechanical weeding or herbicides applications. A novel concept of a precision drill was developed to achieve an advanced control of seed placement and location in the soil. The fundamental principle adopted, was to trap seeds inside holes in the soil, to eliminate seed bounce and roll in the furrow. The concept is simple and consists of only three moving parts, two punch wheels and a fen, to precisely place the seeds in the soil. A rotary punch planter prototype was designed and built, including a vacuum operated seed metering unit and an air delivery system. The prototype was tested under laboratory conditions to determine its performance in relation to seed placement, when planting wheat and pelleted sugar beet seeds. The experiments were done in a soil bin at 4, 6 and 8 km/h Seed spacing and depth were set to 18 cm and 3 cm, respectively. The results show that, once a seed had been successfully selected the prototype had the ability to precisely place seeds in the soil for wheat and sugar beet seeds, at all speeds tested. The grand mean for precision was 12.2%. The CP3 value for wheat and sugar beet at 8 km/h were 26.2 % and 60.8 %, respectively. The main problems encountered were seed selection at higher speeds, and incorrect seed transfers from the seed metering unit to the delivery punches, which occurred for both seeds at all speeds. The concept has proved to be effective and modifications of the seed metering mechanism to improve its performance is recommended to further improve upon the concept.Item Open Access The design of an improved efficiency lavender harvester(2005-01) Dimitriadis, Christos I.; Brighton, James L.The introduction of new methods to solve a specific task was always the ignition for the human mind to find new solutions. Considering the new demands in mechanical lavender harvest for oil production a novel harvester has been developed employing the stripping technique (Klinner et al., 1986a,b,c,d; Hobson et al., 1988) developed for the harv~~ting of cereals. The harvester works in a unique way for this crop by removing the flower :~eads_ in the field, leaving the majority of the stems intact. Convention~! harvesting methods such as hand harvest and mechanical harvest using a . cutting mechanism collects both the flower head and a cut length of the stem. This was found to be an inefficient method for the harvest of lavender because most of the oil produced by the plant (97.5 % by weight - Venskutonis, 1997) is located on the flower. Also using these methods the amount of stem collected increases the transportation and the distillation costs, generates more demanding designs, and removes the stem from the field that could otherwise be left as a natural nutrient. Taking this into account and that the British Pharmacopoeia directs that in making the most refined lavender oil (for medicinal use) it should be distilled from the flowers after they have been separated (stripped) from their stalks (Grieve, 2001) the proposed harvesting technique is ideal for the production of high quality lavender oil.Item Open Access Development of CNC prototype for the characterization of the nanoparticle release during physical manipulation of nanocomposites(Taylor & Francis, 2016-02-18) Gendre, Laura; Marchante, Veronica; Abhyankar, Hrushikesh; Blackburn, Kim; Temple, Clive; Brighton, James L.This work focuses on the release of nanoparticles from commercially used nanocomposites during machining operations. A reliable and repeatable method was developed to assess the intentionally exposure to nanoparticles, in particular during drilling. This article presents the description and validation of results obtained from a new prototype used for the measurement and monitoring of nanoparticles in a controlled environment. This methodology was compared with the methodologies applied in other studies. Also, some preliminary experiments on drilling nanocomposites are included. Size, shape and chemical composition of the released nanoparticles were investigated in order to understand their hazard potential. No significant differences were found in the amount of nanoparticles released between samples with and without nanoadditives. Also, no chemical alteration was observed between the dust generated and the bulk material. Finally, further developments of the prototype are proposed.Item Open Access Driver behaviour characterization using artificial intelligence techniques in level 3 automated vehicle.(Cranfield University, 2021-09) Yang, Lichao; Zhao, Yifan; Brighton, James L.Autonomous vehicles free drivers from driving and allow them to engage in some non-driving related activities. However, the engagement in such activities could reduce their awareness of the driving environment, which could bring a potential risk for the takeover process in the current automation level of the intelligent vehicle. Therefore, it is of great importance to monitor the driver's behaviour when the vehicle is in automated driving mode. This research aims to develop a computer vision-based driver monitoring system for autonomous vehicles, which characterises driver behaviour inside the vehicle cabin by their visual attention and hand movement and proves the feasibility of using such features to identify the driver's non-driving related activities. This research further proposes a system, which employs both information to identify driving related activities and non-driving related activities. A novel deep learning- based model has been developed for the classification of such activities. A lightweight model has also been developed for the edge computing device, which compromises the recognition accuracy but is more suitable for further in-vehicle applications. The developed models outperform the state-of-the-art methods in terms of classification accuracy. This research also investigates the impact of the engagement in non-driving related activities on the takeover process and proposes a category method to group the activities to improve the extendibility of the driving monitoring system for unevaluated activities. The finding of this research is important for the design of the takeover strategy to improve driving safety during the control transition in Level 3 automated vehicles.Item Open Access The evaluation and calibration of pressure mapping system for the measurement of the pressure distribution of agricultural tyres(Elsevier, 2015-01-06) Misiewicz, Paula A.; Blackburn, Kim; Richards, Terence E.; Brighton, James L.; Godwin, RichardThe accuracy of a commercial pressure mapping system was evaluated and a number of techniques for the improvement of pressure measurements were developed. These were required in order to use the pressure mapping system in a tyre/surface interaction study which involved determination of the tyre contact pressure distribution on, both, hard and soil surfaces. In the evaluation of the system, the effect of sensor calibration procedures on the accuracy of the system in measuring pressure was investigated. A purpose built pressure calibration chamber was used to calibrate the sensors, which enabled the proprietary built-in calibration system to be evaluated along with a novel calibration procedure employing, both, an individual and multi-point calibration of each sensing element and the rejection of sensing elements that did not conform to the sensitivity of the majority of the sensing elements. These measures reduced the uncertainty in pressure measurements from ±30% to ±4%. Further, evaluation of the compliance of the material was also conducted to enable the sensors to be used for interface pressure measurements between two different surface materials other than those used during sensor calibration. As a result, a procedure for normalising the recorded pressure by adjusting the recorded load output to equal the applied load was established. The improvement of the accuracy of the sensors made it possible for the system to be used to determine the pressure distribution resulting from a range of tyres on a hard surface and in the soil profile.Item Open Access Evaluation and proposal for a new PMC Pea Harvester Support System(Cranfield University, 2008-01-02) Coalter, Neil; Brighton, James L.PMC Harvesters Ltd is an OEM (Original Equipment Manufacturer) for the pea and bean market. Their primary product line is a self propelled harvester known as the 979 CT harvester. The 979 CT is of considerable proportions being 4m x 4m x 12m in overall dimensions, six wheel drive and weighs 29,620 kg GVW (Gross Vehicle Weight) when fully laden. The aim of this work was to identify and outline possible solutions for the support system (tyre or track and undercarriage), quantify the performance of each system, produce a design and evaluation method to determine an optimal structural specification and to produce a design recommendation for the application. Analysis of the current 979 CT harvester wheel configuration highlighted many constraining factors in tyre choice. The most pertinent of these was that the wheels have a very limited operating space and following a study of the possible tyre options it became apparent only two manufactures, Michelin and Trelleborg, could provide tyres which met the vehicle parameters. An experiment was conducted to evaluate the performance of the three chosen tyre options. From the findings of these tests it was clear that the optimal tyre for the PMC configuration was the Trelleborg Twin Radial tyre, operating at minimum road inflation pressure (1.6 bar) as designated by Trelleborg. When operating the harvester in its normal working environment the tyre pressure should be set at minimum road inflation for in-field conditions with a DBD (Dry Bulk Density) of > 1.3 g/cm3, as excess damage caused by operating above minimum field operating pressure is superficial. The use of low compaction equipment such as CTIS (Central Tyre Inflation System) or tracks would not be beneficial to the PMC application. The track tested created a hardened track pan, thus requiring more effort to rectify post harvest. A CTIS increases the consumption of diesel and offered no reduction in soil compaction below plough depth as shown by the findings from operating the optimal tyre at minimum field inflation pressure (1.2 bar). The primary objective of this project was to offer solutions to reduce the effects of the PMC harvester’s weight on its operating medium. The first natural step was to assess the vehicles main structure in order to improve its performance to weight ratio. The initial phase of this process was to validate the modelling and analyses techniques used to assess the structure. This was done within a controlled test environment at CU@S and from this work a factor of safety of 10% was designated to be applied to all analysis in order to authenticate results and generate a “worst case” answer. Revisions of the main chassis, main pivot and rear axle assemblies were created and analysed. Test metrics were defined which represented operating patterns of the harvester. The findings from these tests saw a 22.6% weight reduction, 43.1% increase in life expectancy and 10.2% reduction in peak stress in the main chassis and main pivot. Unlike the other two key assemblies, the rear axle was deemed fit for purpose and would not benefit from any further design changes.Item Open Access An investigation into the design of precision weeding mechanisms for inter or intra-row weed control(Cranfield University, 2007-10) Dedousis, Athanasios; Godwin, R. J.; Brighton, James L.There is an increasing interest in the use of mechanical intra-row weeders because of concern over environmental degradation and a growing demand for organically produced food. The aim of this study was to investigate the factors that influence the design of precision weeding mechanisms for inter-and intra-row weed control. The purpose is to increase the understanding of the dynamics of the soil-machine interactions and to develop a system for either organic farming or to reduce the environmental loading of agrochemicals in conventional agriculture. Both the graphical computer simulation studies and the use of a mathematical model (O’Dogherty et al., 2007) for the kinematics of discs were used as tools to aid the disc design to determine the optimum geometric characteristics for a rotating disc that will be able to treat the intra-row area between the crop plants undisturbed circle. The model has wide applicability for the interactive design of discs for a range of crops. A force prediction model for shallow asymmetric static and rotating discs (about a vertical axis) developed to predict the forces on rotating discs. The model takes into account the geometric parameters of the discs, the speed of operation, the working depth and the physical properties of the soil based upon those required for the general soil mechanics equation which obeys the Mohr-Coulomb failure criterion. A comparison of all experimental work encompassing the laboratory experiments with non-rotating and rotating discs, incorporating the deflection effect of the shaft when working at 0o inclination angle showed that the model is able to predict the draught force with good accuracy. The predicted forces were 3.5% more than the measured forces overall for a linear regression line (with a coefficient of determination of 0.7) and 61% of the data were within bounds of ± 25% a line of equal magnitude. The effect of working depth, inclination angle and disc geometry on draught and penetration force requirements for flat and convex discs were assessed under controlled laboratory conditions. Because of its simplicity a flat disc was an obvious one to study as it is a circular blade with incorporating a cut-out sector, whilst the convex disc has the advantage of underside clearance. The effect of the concavity on soil failure proved to be of interest by providing smaller aggregates. Four inclination angles (0o - 15o) were examined at 0.5 m s-1 (1.8 km h-1) driving speed and 1 rev s-1 rotational speed at 10 mm deep. Four depths (10 mm - 25 mm) were examined at 0.5 m s-1 driving speed and 1 rev s-1 rotational speed at 10 mm deep and 0o inclination angle were tested under controlled conditions. Inclination angle and disc geometry had a significant effect on disc forces and soil failure. A small increase in inclination angle to the direction of travel reduces the magnitude of draught and vertical force by 70% and 80% respectively on average for both flat and convex disc geometries. The convex disc requires 15% less draught force than an equivalent flat disc. This allowed the optimum working parameters for a disc to be selected to eliminate the weeds with the minimum force requirements. The results of a field experiment after 16; 23; and 33 days transplanting with a working speed of 0.5 m s-1 (1.8 km h-1) showed that the proposed novel mechanical weed control system can achieve a weed reduction within the crop row up to 87%. The disc-hoe has a lower cost for an area of 125 ha of £81 ha-1,in comparison to £139 ha-1 for the inter-row and hand weeding combination and £690 ha-1 for a six man gang manual intra-row weeding, for two passes. It is also less expensive than the cost of the 24 m tractor mounted sprayer of £100 ha-1 The use of the rotating disc-hoe for mechanical weed control would have the benefits of lower mechanical weeding cost, increased potential for organic production and reduction in the number of weeding operations through better targeting to minimise problems caused by frequent soil disturbance and reduced herbicide use having the benefits of environmental advantage.Item Open Access Localised low velocity impact performance of FLAX/PLA biocomposites(Cranfield University, 2015-06) Nassiopoulos, Elias; Njuguna, James; Brighton, James L.Natural fibre composites are fast emerging as a viable alternative to traditional materials and synthetic composites. Their low cost, lightweight, good mechanical performance and their environmentally friendly nature makes them an ideal choice for the automotive sector. The automotive industry has already embraced these composites in production of non-structural components. At present, however, research studies into composites made of natural fibres/bio-sourced thermoplastic resins are at infancy stage and such works are rare in the literature. This study therefore focuses on the mechanical properties of poly(lactic) acid (PLA) flax reinforced composites for structural loaded components. The aim was to investigate the performance of flax/PLA biocomposites subjected to localized low velocity impacts. To start with, a detailed literature study was conducted covering biocomposites and PLA in particular. Next, a series of composite samples were manufactured. Morphological and thermal studies were also conducted in order to develop an in-depth understanding of their thermo-mechanical properties, including crystallinity, thermal response and their related transition temperatures. This was followed by localized impact studies. The influence of temperature, water uptake and strain rates to the material tensile strength and modulus, as well as the damage characteristics and limits that lead to failure were studied. Furthermore, in the present work different methods and existing material models to predict the response of biocomposites were assessed. A case study was then performed using these models to understand, develop and improve the side crash performance of a superlight city car prototype. ...[cont.]Item Open Access Mathematical modelling and simulation of continuous, highly precise, metal/eco-friendly polymerization of Lactide using alternative energies for reaction extrusion(Cranfield University, 2016-07) Dubey, Satya P.; Abhyankar, Hrushikesh; Brighton, James L.Polylactic acid (PLA) is one of the most promising bio-compostable and biodegradable thermoplastic made from renewable sources. PLA, is typically obtained by polymerising lactide monomer. The technique mainly used for ring opening polymerization (ROP) of Lactide is based on metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts in suitable solvent. However, the PLA synthesized using such catalysts may contain trace elements of the catalyst, which may be toxic. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)2 and tri-phenyl phosphine (PPh)3 were considered to perform ROP of lactide monomer using ultrasound as an alternative energy (AE) source for activating and/or boosting the polymerization. Mathematical model of ROP of lactide, was developed to estimate the impact of reaction kinetics and AE source on the polymerization process. Ludovic® software, a commercial code was used. It was adopted for the simulation of continuous reactive extrusion of PLA. Results from experiments and simulations were compared to validate the simulation methodology. Results indicate that the application of AE source in reaction process boost the PLA formation rate. Result obtained through Ludovic simulation and experiments were validated. It was shown that there is a case for reducing the residence time distribution (RTD) in Ludovic due to the ‘liquid’ monomer flow in the extruder. This change in the parameters resulted in validation of the simulation. However, it was concluded that the assumption would have to be established by doing further validations.The simulation model includes the details of kinetics of reactions involved with in the process and helps to upscale the reaction output. This work also estimates the usefulness and drawbacks of using different catalysts as well as effect of alternative energies and future aspects for PLA production.Item Open Access Mechanical properties and impact energy absorption of hybrid thermoplastic nanocomposite structures(2016-01) Silva, Francesco; Abhyankar, Hrushikesh; Brighton, James L.This thesis focuses on the mechanical properties and the impact energy absorption capabilities of injection moulded hybrid three-phase polymer composites. Its main aim is to investigate the effect of different micro and nano sized filers on the mechanical properties; such as stiffness, strength, ductility, impact resistance and energy absorption capability; of short-fibre reinforced thermoplastic composites. Extensive experimental and numerical investigations were core to the research. Six different, three-phase composites, were manufactured by the integration of two types of nano-reinforcements (either nano-silica or nano-clay), or micro glass-spheres, into two types of short glass-fibre reinforced thermoplastic matrices (either Polypropylene (PP) or Polyamide (PA6)). The materials were characterized using Transmission Electron Microscopy (TEM), Wide Angle X Ray Diffraction (WAXD) and optical microscopy. The effect of matrix and reinforcement material on the mechanical properties and the energy absorption capabilities of polymer composites were studied in detail. The results are compared with the properties of standard two-phase glass-fibre reinforced polymer composites. Initial experiments focused on quasi-static uniaxial tensile and compression tests, as well as quasi-static crash tests of the conical structures. Subsequently, dynamic drop weight impact crash tests of the conical structures were conducted to investigate the influence of the nano reinforcement on the energy absorption capabilities of the polymer composites. To study propagation of the dynamic cracks and the energy absorbing mechanism, the impact event was recorded using a high-speed camera. The fracture surface was investigated with scanning electron microscopy (SEM). Furthermore, improved simulation tools were developed to accurately and effectively model nanocomposite structures subjected to dynamic loads. A constitutive model with orthotropic yield, strain rate sensitivity and strain energy density based failure criterion, was developed and implemented into Ls Dyna Finite Element (FE) code. The results show that by changing the filler and the matrix material, it is possible to control the mechanical properties and the energy absorption capability of the glass-fibre reinforced polymer nanocomposites. An increase in the mechanical properties (stiffness, strength or ductility) of PA6 composites was observed. Furthermore, nano-silica and glass-spheres reinforcements were found to improve the energy absorption capabilities of PA6 composites by changing the mode of failure, whereas nano-clay reinforcement caused a decrease in that capability. Little or negative influence of the nano-fillers was observed, when combined with PP based composites. The experimental findings were used to generate, calibrate and validate the user defined material model. The structural FE modelling proved that the model was capable of accurately and effectively representing the nanocomposite structures subjected to static and dynamic loads. Furthermore, it provided a valuable input for better understanding of the structural failure mechanism, observed in the three-phase nanocomposite structures.Item Open Access Microwave energy assisted synthesis of poly lactic acid via continuous reactive extrusion: modelling of reaction kinetics(Royal Society of Chemistry, 2017-03-27) Dubey, Satya P.; Abhyankar, Hrushikesh; Marchante, Veronica; Brighton, James L.; Bergmann, Björn; Trinh, Giang; David, ChantalThe most commonly used batch process to manufacture PLA is ring opening polymerization (ROP) of lactide monomer in a suitable solvent, in the presence of a metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts. However, this process does not lend itself to safer/cleaner and high throughput (and high volume) manufacturing. Continuous reactive extrusion of lactide monomer using a suitable reaction input has the potential to increase the throughput, and this route has been explored in the literature. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)2 and tri-phenyl phosphine (PPh)3, were considered to perform ROP of lactide monomer using the microwave as an alternative energy (AE) source for activating and/or boosting the polymerization. Implementation of a microwave generator in a section of the extruder is one of the novelties of this research. A simulation model of ROP of PLA was formulated to estimate the impact of reaction kinetics and AE source on the polymerization process. Ludovic® software was used for the simulation of continuous reactive extrusion of the process. Experimental and simulated results were compared for the validation of the methodology. This work also highlights the advantages and drawbacks of most conventional metal catalysts, the effect of alternative energies on reaction mechanism, and safe and efficient production of PLA.Item Open Access Modelling and validation of synthesis of poly lactic acid using an alternative energy source through a continuous reactive extrusion process(MDPI, 2016-04-22) Dubey, Satya P.; Abhyankar, Hrushikesh; Marchante, Veronica; Brighton, James L.; Blackburn, Kim; Temple, Clive; Bergmann, Björn; Trinh, Giang; David, ChantalPLA is one of the most promising bio-compostable and bio-degradable thermoplastic polymers made from renewable sources. PLA is generally produced by ring opening polymerization (ROP) of lactide using the metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts in a suitable solvent. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)2 and tri-phenyl phosphine (PPh)3 were considered to perform ROP of lactide. Ultrasound energy source was used for activating and/or boosting the polymerization as an alternative energy (AE) source. Ludovic® software, designed for simulation of the extrusion process, had to be modified in order to simulate the reactive extrusion of lactide and for the application of an AE source in an extruder. A mathematical model for the ROP of lactide reaction was developed to estimate the kinetics of the polymerization process. The isothermal curves generated through this model were then used by Ludovic software to simulate the “reactive” extrusion process of ROP of lactide. Results from the experiments and simulations were compared to validate the simulation methodology. It was observed that the application of an AE source boosts the polymerization of lactide monomers. However, it was also observed that the predicted residence time was shorter than the experimental one. There is potentially a case for reducing the residence time distribution (RTD) in Ludovic® due to the ‘liquid’ monomer flow in the extruder. Although this change in parameters resulted in validation of the simulation, it was concluded that further research is needed to validate this assumption.Item Open Access Nanoparticle reinforced polyamide 66 glass fibre composites for automotive under-the-bonnet-applications.(2016-10) Butterworth, Ian; Abhyankar, Hrushikesh; Brighton, James L.This work focus on an engine oil pan application which expects component materials operate at elevated temperatures due to returning oil heating up during operation. Mechanical properties of thermoplastic composites are known to be temperature dependent with performance losses elevated temperatures. A pilot study was conducted to benchmark the current state-of-the-art glass reinforced polyamide materials at elevated temperatures to address a gap in this knowledge. Experiments included tensile, 3-point flexural, and gas gun impact where conducted at elevated temperatures 23°C, 65°C, 90°C and 120°C. Experimental results demonstrated the trade-off in the mechanical properties of the two materials especially when one of the materials had been impact modified with an elastomer (PA66-GF-E). PA66-GF-E mechanical and impact performance can be considered fit of purpose as a suitable material for an oil pan application but is more expensive. As an extra compounding step is required to graft the elastomer to the PA66 matrix. Literature studies into replacements for the elastomer suggested nanoparticles as they can be compounded at the same time as the GF and in turn eliminate secondary compounding costs. Six 3-phase nanocomposite where then compounded using a twin screw extruder. Additions of OMMT and SiO2where done in 2, 3 and 4wt.% for each nanocomposite. Testing of the 3-phase nanocomposites indicated the GF reduction has reduced mechanical strength in all results, but still demonstrates each nanomaterial and volume has been successful. Thermomechanical testing and aging suggests an optimised SiO2 in wt.% of 2 or 3 could replace an elastomer as an impact modifier. OMMT grades did not have a significant improvement to over the SiO2 grades to consider suitable for the oil pan application. However this work does builds a strong case for further work to continue developing 3-phase nanocomposites by improving the compounding setup.Item Open Access Pontryagin's Minimum Principle based model predictive control of energy management for a plug-in hybrid electric bus(Elsevier, 2018-12-17) Xie, Shaobo; Hu, Xiaosong; Xin, Zongke; Brighton, James L.To improve computational efficiency of energy management strategies for plug-in hybrid electric vehicles (PHEVs), this paper proposes a stochastic model predictive controller (MPC) based on Pontryagin’s Minimum Principle (PMP), which differs from widely used dynamic programming (DP)-based predictive methods. First, short-time speed forecasting is achieved using a Markov chain model, based on real-world driving cycles. The PMP- and DP-based MPCs are compared under four preview horizons (5 s, 10 s, 15 s and 20 s), and the results show that the computational time of the DP-MPC is almost four times of that in the PMP-MPC. Moreover, the influence of predication horizon length on computational time and energy consumption is examined. Given a preview horizon of 5 s, the PMP-MPC holds a total energy consumption cost of 7.80 USD and computational time per second of 0.0130 s. When the preview horizon increases to 20 s, the total cost is 7.77 USD with the computational time per second increasing to 0.0502 s. Finally, DP, PMP, and rule-based strategies are contrasted to the PMP-MPC method, further demonstrating the promising performance and computational efficiency of the proposed methodology.Item Open Access Progress in environmental-friendly polymer nanocomposite material from PLA: synthesis, processing and applications(Elsevier, 2017-07-10) Dubey, Satya P.; Thakur, Vijay Kumar; Krishnaswamy, Suryanarayanan; Abhyankar, Hrushikesh; Marchante, Veronica; Brighton, James L.The disposal of large amounts of waste from daily use polymers is among one of the foremost concerns in the current era. Effective utilization of bio-renewable materials procured from natural sources has been proposed as a potential solution to this problem. Among such different polymers, Poly lactic acid (PLA) which is a bio-degradable polymer, resembles quite promotable features, which can be polymerized from sustainable sources as chips sugarcane, starch and corn. Ring-opening polymerization (ROP) of Lactide (LA) monomer considering catalysts such as Al, Sn or Zn is one of the efficient methods for the PLA synthesis. However, the PLA polymerized through this type of catalysts may contain trace elements of the catalyst. Due to their carcinogenic nature, the traces of such catalysts should be (ideally) removed from the synthesis process. The use of alternative energy (AE- UV, Microwave) sources could be a potential route. Alternative development of non-metal catalysts is best alternatives for the processing of PLA through ROP. PLA layer based composite materials are gaining huge interest due to their multiple application (food, medical etc.) as eco-friendly material. In this article, we review on the implementation of AE sources for PLA processing and to populate the current state-of-the-art associated with the PLA research, especially application in nanocomposite materials field.Item Open Access A study of emission of nanoparticles during physical processing of aged polymer-matrix nanocomposites(Cranfield University, 2016-11) Gendre, Laura; Abhyankar, Hrushikesh; Brighton, James L.Nanotechnology research and its commercial applications have experienced an exponential rise in the recent decades. Although there are a lot of studies with regards to toxicity of nanoparticles, the exposure to nanoparticles, both in terms of quality and quantity, during the life cycle of nanocomposites is very much an unknown quantity and an active area of research. Unsurprisingly, the regulations governing the use and disposal of nanomaterials during its life cycle are behind the curve. This work aims to assess the quantity of nanoparticles released along the life cycle of nanocomposites. Machining operations such as milling and drilling were chosen to simulate the manufacturing of nanocomposites parts, and impact testing to recreate the end-of-life of the materials. Several studies have tried to simulate different release scenarios, however these experiments had many variables and in general were not done in controlled environments. In this study, a reliable method was developed to assess the release of nanoparticles during machining and low velocity impact of nanocomposites. The development and validation of a new prototype used for measurement and monitoring of nanoparticles in a controlled environment is presented, as along with release experiments on different nanocomposites. Every sample tested was found to release nanoparticles irrespective of the mechanical process used or the type of material tested. Even neat polymers released nanoparticles when subjected to mechanical forces. The type of matrix was identified to play a major role on the quantity of nanoparticles release during different process. Thermoset polymers (and especially polyester) were found to release a higher number concentration of particles, mainly due to their brittle properties. A polyester sample was found to release up to 48 times more particles than a polypropylene one during drilling. The nanofiller type and percentage used to reinforce the polymer is also a key point. For example, the addition of 2 wt.% of nano-alumina into polyester increases the number concentration of particles by 106 % following an impact. The nanofiller chosen and its quantity affect the mechanical properties and machinability of the composites and therefore its nanoparticles release potential. The mechanical process and the process parameters chosen were also found to be crucial with regards to the nanoparticles released with different trends observed during drilling and impact of similar materials. Finally, thermal ageing of nanocomposites increases the number concentration of nanoparticles released (by 8 to 17 times after 6 weeks).Item Open Access Tractive performance of 4x4 tyre treads on pure sand.(2002-12) Eatough, Kieron; Brighton, James L.This thesis examined the difficulties of generating traction from 4x4 (light truck) tyres in pure sand conditions. Investigations conducted in the Cranfield University Soil Dynamics Laboratory measured the tractive performance of a range of production and prototype 4x4 tyre tread patterns to quantify the effect of tread features upon tractive performance. The investigation also quantified the amount of sand displacement instantaneously occurring beneath the tyre, by a novel application of radio frequency identification (RFID) technology, which determined sand displacements to an accuracy of ±5.5 mm. A limited number of normal contact stress measurements were recorded using a TekScan normal pressure mapping system. This technology was employed in a new manner that allowed pressure distributions to be dynamically recorded on a deformable soil surface. Models were developed or adapted to predict rolling resistance, gross thrust of a tyre and the gross thrust effect due to its tread. Net thrust was predicted from refined versions of equations developed by Bekker to predict gross thrust and rolling resistance. These were modified to account for dynamic tractive conditions. A new tread model proposed by the author produced a numerical representation of the gross thrust capability of a tread based on factors hypothesised to influence traction on loose sand. This allowed the development of a relationship between the features of the tread and its measured gross thrust improvement (relative to a plain tread tyre), from which a total relationship was developed. The tread features were also, in combination with the wheel slip, related to the sand displacements and net thrusts simultaneously achieved. The sand displacement results indicated that the majority of the variation in displacement between the different treads occurred in the longitudinal (rearward) direction. This effect was influenced by the wheel slip, as increased slip caused greater displacements, so the differences between the treads were greater at higher slips. The treads that generated the highest relative displacements also derived the higher gross thrusts (up to +5% extra gross thrust compared to a plain tread), although at the higher slips this also caused increased sinkage. As sinkage increased, the rolling resistance increased at a fester rate then the gross thrust, and thus the net thrust reduced. To prevent this effect the wheel slip should be limited to a maximum of 20% at low forward speeds (approximately 5 km/h). Current market forces dictate that the biggest benefit that tyre manufacturers could offer in desert market regions would be to optimise road-biased tyres to suit loose sand conditions. The modelling developed indicated that this could be achieved by maximising the number of lateral grooves (and thus lateral edges) featured on a tread, however care would have to be exercised so as not to compromise the necessaiy on-road capability. The models could also be used to quantifiably determine from a choice of possible tyre treads, the tread that would offer most traction on pure loose sand.Item Open Access Tyre / soil interaction modelling within a virtual proving ground environment(Cranfield University, 2012-01) Wright, A.; Brighton, James L.Off-road mobility defines the ability of land-based vehicles to accelerate, pull loads and climb gradients. Historically, much of the work completed to relate mobility to vehicle and terrain characteristics has been empirical in nature, and has therefore been susceptible to errors caused by the inherent variability of naturally occurring soils. This thesis addresses the off-road mobility of wheeled vehicles, and in particular the use of a finite element (FE) based approach to predict performance metrics such as rolling resistance, drawbar pull and tractive efficiency. Tools to predict these measures of performance have a wide range of applications, including military, agricultural and leisure vehicles, aircraft operating from temporary airfields and planetary landing craft. The current study extends the virtual proving ground (VPG) concept, where a single vehicle model can be subjected to a series of virtual test conditions, to include the assessment of off-road mobility. Throughout, modelling has been carried out using LS-DYNA, a commercially available non-linear dynamic analysis code. Unlike previous studies using FE techniques to investigate wheel / soil interaction, an Eulerian representation of the soil has been employed, which permits a consistent approach to be applied to both purely cohesive and purely frictional soils, as well as those displaying a combination of cohesive and frictional behaviour. At each stage of the research, the validity of the FE-based modelling approach has been assessed using data from controlled experimental testing at Cranfield University’s off-road dynamics facility. A key finding of the work completed is that rate sensitivity in moisture containing soils can significantly affect the accuracy of (empirical, analytical and numerical) model predictions, even at low translational speeds (less than 0.1m/s). This finding highights the adverse impact of simplifications in many previous experimental and modelling studies, which have assumed that rate effects may be ignored providing the translational speed of the vehicle is low.