We aim to enhance the stability of finite element models of dynamic structural contact with multi... more We aim to enhance the stability of finite element models of dynamic structural contact with multiphase granular soils which are described by advanced soil plasticity models that can simulate monotonic and cyclic behaviour of multiphase soils. Often, numerical oscillations cannot be avoided in these contact models and can cause advanced soil models to significantly overshoot stress, leading to unrealistic discontinuities in the stress paths. This situation can challenge the stability of the stress integration scheme and the global finite element solver and lead to the early termination of the analysis. We specifically address the issue of stress overshooting by presenting novel solutions and the corresponding stress integration schemes for a representative soil model for unsaturated granular soils. Also, several examples are provided to evaluate the integration scheme and show the advantages and limitations of the proposed overshooting solutions in solving a contact-impact problem in...
This study aims to develop an innovative retrofittable platform with cutting-edge hardware and so... more This study aims to develop an innovative retrofittable platform with cutting-edge hardware and software tools to advance the current state of intelligent compaction technology. We built a prototype of this platform from the ground up, hereafter referred to as the Intelligent Compaction Analyser (ICA) platform. This platform is designed to provide the following novel features: [i] simultaneous visualisation of multiple intelligent compaction measurement values (ICMVs) in real-time during compaction; [ii] versatility to retrofit to an existing conventional roller; [iii] ability to incorporate corrections for different ICMV parameters reflecting variable field conditions; [iv] customization of construction specifications as needed for performance-based compaction; [v] ability to record key roller parameters such as speed, vibration frequency and amplitude for further analysis; and (vi) capability to monitor the raw vibration signal pattern and its frequency spectrum. In this paper, we ...
A substantial proportion of roads, especially in developing countries, remain unsealed. Monitorin... more A substantial proportion of roads, especially in developing countries, remain unsealed. Monitoring of traffic-induced dust is an essential part of unsealed road maintenance. The measurement of the degree of severity of dust emissions is a challenging task due to dust's spatio-temporal characteristics, the requirement for expensive equipment, and rapidly changing environmental conditions. The next evolution of mobility solutions for unsealed roads calls for more robust, time-efficient and smart methods, such as machine learning techniques to solve dust-related road problems. This paper investigates the performance of current semantic segmentation machine learning models on the identification of dust clouds using the previously published URDE dataset. Based on static image performance, the selected models are then used to identify and segment dust clouds in video recordings of road dust emissions. These are used to visually analyse the segmentation quality of the best-performing m...
Unmanned aerial vehicle (UAV) assisted photogrammetry has been used to perform a non-contact meas... more Unmanned aerial vehicle (UAV) assisted photogrammetry has been used to perform a non-contact measurement of the covers on the anaerobic wastewater lagoons at Melbourne Water Corporation’s Western Treatment Plant (WTP). These floating covers are valuable assets that eliminate odour and greenhouse gas emissions and harvest the methane-rich biogas as a renewable resource to generate electricity. Hence, the state of deformation of the floating covers becomes an important engineering factor for structural integrity assessment. UAVs have been deployed to scan these covers and photogrammetry has been used to process the aerial images to construct the floating covers’ orthophoto and digital elevation model (DEM). This paper proposes to adopt the finite element formulation to improve the quantification of the in-plane movement of a floating cover. Distinguishable features on the floating cover are first identified and their (x, y and z) coordinates are recorded over time. The results show th...
Water pipeline condition monitoring is a challenging task that requires in-depth research and inv... more Water pipeline condition monitoring is a challenging task that requires in-depth research and investigation. Leakages in pipelines can waste large quantities of water daily and affect the quality of the water supply. Detection, quantification, and accurate localisation of leaks can significantly improve the service delivered. In this context, a ‘contact-less’ optical fibre sensor package was developed with the ability to measure pressure and detect vibration in pipe. This study provides a description of the developed sensor and presents the findings from a set of experiments with the sensor package deployed inside a pressurised pipe. Results indicate that the proposed sensing strategy for leak detection and quantification is robust and promising.
Transient based technique is known as one of the most economical ways for pipeline condition asse... more Transient based technique is known as one of the most economical ways for pipeline condition assessment. This technique involves monitoring and analysing pressure transient profiles at multiple points in a distributed system. Its application is restricted due to its low spatial resolution (10 m). It is hypothesised that by increasing the number of pressure transducers and reducing the gauge length (distance between the transducers), the spatial resolution of the measurements would highly be improved. However, the deployment of pressure transducers is restricted to the location of the hydrants. In this paper, a submersible quasi-distributed optical fibre based pressure sensors were proposed, constructed and tested in laboratory to verify this concept. For this context, this paper describes the proposed optical device and presents some preliminary analysis and results obtained from a set of experiments. The experimental results show that using the quasi-distributed optical fibre based...
Intelligent compaction involves using instrumented rollers to provide real-time monitoring of the... more Intelligent compaction involves using instrumented rollers to provide real-time monitoring of the compacted ground using sensors such as accelerometers and GPS. This technology has the potential to improve productivity and uniformity in construction but its advancement is currently impeded due toinaccurate estimation of the physical ground properties, such as dry density, and the absence of robust quantitative models to predict the effect of compaction on the long-term performance of unsaturated soils under repeated loads. In this study, the compaction of the soil layers and subsequent deformations under repeated traffic loads are simulated by using an advanced computational framework and model for unsaturated soils. By employing an effective stress concept, the presented computational approach allows a unified description of soils at various degrees of saturation. In addition, the model can capture plastic deformations at the initiation of loading and thereby offer accurate predict...
We aim to enhance the stability of finite element models of dynamic structural contact with multi... more We aim to enhance the stability of finite element models of dynamic structural contact with multiphase granular soils which are described by advanced soil plasticity models that can simulate monotonic and cyclic behaviour of multiphase soils. Often, numerical oscillations cannot be avoided in these contact models and can cause advanced soil models to significantly overshoot stress, leading to unrealistic discontinuities in the stress paths. This situation can challenge the stability of the stress integration scheme and the global finite element solver and lead to the early termination of the analysis. We specifically address the issue of stress overshooting by presenting novel solutions and the corresponding stress integration schemes for a representative soil model for unsaturated granular soils. Also, several examples are provided to evaluate the integration scheme and show the advantages and limitations of the proposed overshooting solutions in solving a contact-impact problem in...
This study aims to develop an innovative retrofittable platform with cutting-edge hardware and so... more This study aims to develop an innovative retrofittable platform with cutting-edge hardware and software tools to advance the current state of intelligent compaction technology. We built a prototype of this platform from the ground up, hereafter referred to as the Intelligent Compaction Analyser (ICA) platform. This platform is designed to provide the following novel features: [i] simultaneous visualisation of multiple intelligent compaction measurement values (ICMVs) in real-time during compaction; [ii] versatility to retrofit to an existing conventional roller; [iii] ability to incorporate corrections for different ICMV parameters reflecting variable field conditions; [iv] customization of construction specifications as needed for performance-based compaction; [v] ability to record key roller parameters such as speed, vibration frequency and amplitude for further analysis; and (vi) capability to monitor the raw vibration signal pattern and its frequency spectrum. In this paper, we ...
A substantial proportion of roads, especially in developing countries, remain unsealed. Monitorin... more A substantial proportion of roads, especially in developing countries, remain unsealed. Monitoring of traffic-induced dust is an essential part of unsealed road maintenance. The measurement of the degree of severity of dust emissions is a challenging task due to dust's spatio-temporal characteristics, the requirement for expensive equipment, and rapidly changing environmental conditions. The next evolution of mobility solutions for unsealed roads calls for more robust, time-efficient and smart methods, such as machine learning techniques to solve dust-related road problems. This paper investigates the performance of current semantic segmentation machine learning models on the identification of dust clouds using the previously published URDE dataset. Based on static image performance, the selected models are then used to identify and segment dust clouds in video recordings of road dust emissions. These are used to visually analyse the segmentation quality of the best-performing m...
Unmanned aerial vehicle (UAV) assisted photogrammetry has been used to perform a non-contact meas... more Unmanned aerial vehicle (UAV) assisted photogrammetry has been used to perform a non-contact measurement of the covers on the anaerobic wastewater lagoons at Melbourne Water Corporation’s Western Treatment Plant (WTP). These floating covers are valuable assets that eliminate odour and greenhouse gas emissions and harvest the methane-rich biogas as a renewable resource to generate electricity. Hence, the state of deformation of the floating covers becomes an important engineering factor for structural integrity assessment. UAVs have been deployed to scan these covers and photogrammetry has been used to process the aerial images to construct the floating covers’ orthophoto and digital elevation model (DEM). This paper proposes to adopt the finite element formulation to improve the quantification of the in-plane movement of a floating cover. Distinguishable features on the floating cover are first identified and their (x, y and z) coordinates are recorded over time. The results show th...
Water pipeline condition monitoring is a challenging task that requires in-depth research and inv... more Water pipeline condition monitoring is a challenging task that requires in-depth research and investigation. Leakages in pipelines can waste large quantities of water daily and affect the quality of the water supply. Detection, quantification, and accurate localisation of leaks can significantly improve the service delivered. In this context, a ‘contact-less’ optical fibre sensor package was developed with the ability to measure pressure and detect vibration in pipe. This study provides a description of the developed sensor and presents the findings from a set of experiments with the sensor package deployed inside a pressurised pipe. Results indicate that the proposed sensing strategy for leak detection and quantification is robust and promising.
Transient based technique is known as one of the most economical ways for pipeline condition asse... more Transient based technique is known as one of the most economical ways for pipeline condition assessment. This technique involves monitoring and analysing pressure transient profiles at multiple points in a distributed system. Its application is restricted due to its low spatial resolution (10 m). It is hypothesised that by increasing the number of pressure transducers and reducing the gauge length (distance between the transducers), the spatial resolution of the measurements would highly be improved. However, the deployment of pressure transducers is restricted to the location of the hydrants. In this paper, a submersible quasi-distributed optical fibre based pressure sensors were proposed, constructed and tested in laboratory to verify this concept. For this context, this paper describes the proposed optical device and presents some preliminary analysis and results obtained from a set of experiments. The experimental results show that using the quasi-distributed optical fibre based...
Intelligent compaction involves using instrumented rollers to provide real-time monitoring of the... more Intelligent compaction involves using instrumented rollers to provide real-time monitoring of the compacted ground using sensors such as accelerometers and GPS. This technology has the potential to improve productivity and uniformity in construction but its advancement is currently impeded due toinaccurate estimation of the physical ground properties, such as dry density, and the absence of robust quantitative models to predict the effect of compaction on the long-term performance of unsaturated soils under repeated loads. In this study, the compaction of the soil layers and subsequent deformations under repeated traffic loads are simulated by using an advanced computational framework and model for unsaturated soils. By employing an effective stress concept, the presented computational approach allows a unified description of soils at various degrees of saturation. In addition, the model can capture plastic deformations at the initiation of loading and thereby offer accurate predict...
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Papers by Jayantha Kodikara