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Conference Papers by Anu Hanish Nithin

Research paper thumbnail of Optimization of Monitoring and Inspections in the Life-cycle of Wind Turbines

The past decade has witnessed a surge in the offshore wind farm developments across the world. Al... more The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

Papers by Anu Hanish Nithin

Research paper thumbnail of An approach to improve asset maintenance and management priorities using machine learning techniques

Safety and Reliability, Nov 23, 2022

Research paper thumbnail of Reliability and Cost Estimation for Maintenance Planning of Oil and Gas Assets

Volume 2: Structures, Safety, and Reliability, 2021

Safety and reliability of the assets in the Oil and Gas sector is considered critical to maximize... more Safety and reliability of the assets in the Oil and Gas sector is considered critical to maximize availability and minimize downtime in production and operations. The industry, due to ageing assets, are re-visiting the maintenance planning of critical equipment through Reliability-Centered Maintenance (RCM). The RCM process comprises of the hierarchical structuring of technical objects according to their functional locations and further dividing them into their maintainable items and components. Generally, a criticality matrix is developed that would identify the highly critical assets based on criteria such as cost, production, safety, and environment. The Failure Modes and Effects Analysis (FMEA) is then performed for the identified functions, functional failures, and likely failure modes of each component of the asset. The failure modes can be identified from first principles and historical failure data from the asset owner or databases such as the Offshore Reliability Database (...

Research paper thumbnail of A multi-objective framework for the optimisation of life-cycle costs of wind turbines

Multi-objective optimization of the life-cycle costs and reliability of offshore wind turbines (W... more Multi-objective optimization of the life-cycle costs and reliability of offshore wind turbines (WTs) is an area of immense interest due to the widespread increase in wind power generation across the world. Though there has been significant research done in this field for structures such as bridges and offshore oil and gas platforms, less research has been conducted for the costs and reliability optimization of offshore WTs. Most of the existing studies have addressed the conjunction of structural reliability and the Bayesian preposterior analysis for multi-objective optimization. This paper proposes and extension of the previous approaches as a novel framework for multi-objective probabilistic optimization of the total life-cycle costs and reliability of WTs by combining the elements of structural reliability analysis, Bayesian pre-posterior analysis with neuro-fuzzy and evolutionary algorithms. The output of this framework would determine the optimal inspection, monitoring and main...

Research paper thumbnail of Scheduling structural health monitoring activities for optimizing life-cycle costs and reliability of wind turbines

Smart Materials and Nondestructive Evaluation for Energy Systems 2017, 2017

Optimization of the life-cycle costs and reliability of offshore wind turbines (OWTs) is an area ... more Optimization of the life-cycle costs and reliability of offshore wind turbines (OWTs) is an area of immense interest due to the widespread increase in wind power generation across the world. Most of the existing studies have used structural reliability and the Bayesian pre-posterior analysis for optimization. This paper proposes an extension to the previous approaches in a framework for probabilistic optimization of the total life-cycle costs and reliability of OWTs by combining the elements of structural reliability/risk analysis (SRA), the Bayesian pre-posterior analysis with optimization through a genetic algorithm (GA). The SRA techniques are adopted to compute the probabilities of damage occurrence and failure associated with the deterioration model. The probabilities are used in the decision tree and are updated using the Bayesian analysis. The output of this framework would determine the optimal structural health monitoring and maintenance schedules to be implemented during the life span of OWTs while maintaining a trade-off between the life-cycle costs and risk of the structural failure. Numerical illustrations with a generic deterioration model for one monitoring exercise in the life cycle of a system are demonstrated. Two case scenarios, namely to build initially an expensive and robust or a cheaper but more quickly deteriorating structures and to adopt expensive monitoring system, are presented to aid in the decision-making process.

Research paper thumbnail of Optimization of monitoring and inspections in the life-cycle of wind turbines

Smart Materials and Nondestructive Evaluation for Energy Systems 2016, 2016

The past decade has witnessed a surge in the offshore wind farm developments across the world. Al... more The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

Research paper thumbnail of Reliability-centered maintenance and cost optimization for offshore oil and gas components

Journal of Physics: Conference Series, 2021

Reliability-Centered Maintenance (RCM) is widely used for enterprise asset management in the Oil ... more Reliability-Centered Maintenance (RCM) is widely used for enterprise asset management in the Oil and Gas sector. The traditional RCM process encompasses the development of equipment hierarchy, the determination of the functional failure of assets, identification of the critical failure modes and the development of suitable maintenance strategies for these failure modes through RCM logic tree analysis. However, the current industry standards and conditions call for greater strides of production availability and reliability of the assets. The aim of the paper is to deliver RCM oriented cost optimization framework for the assets through the implementation of probabilistic and statistical analysis. Probabilistic analysis of the most critical components predicts the failure over time. The mean time to failure, mean time between failure and mean time to repair parameters are determined from the failure history. The parameters of the probability distribution, for instance, the shape and sc...

Research paper thumbnail of Optimization of Monitoring and Inspections in the Life-cycle of Wind Turbines

The past decade has witnessed a surge in the offshore wind farm developments across the world. Al... more The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

Research paper thumbnail of An approach to improve asset maintenance and management priorities using machine learning techniques

Safety and Reliability, Nov 23, 2022

Research paper thumbnail of Reliability and Cost Estimation for Maintenance Planning of Oil and Gas Assets

Volume 2: Structures, Safety, and Reliability, 2021

Safety and reliability of the assets in the Oil and Gas sector is considered critical to maximize... more Safety and reliability of the assets in the Oil and Gas sector is considered critical to maximize availability and minimize downtime in production and operations. The industry, due to ageing assets, are re-visiting the maintenance planning of critical equipment through Reliability-Centered Maintenance (RCM). The RCM process comprises of the hierarchical structuring of technical objects according to their functional locations and further dividing them into their maintainable items and components. Generally, a criticality matrix is developed that would identify the highly critical assets based on criteria such as cost, production, safety, and environment. The Failure Modes and Effects Analysis (FMEA) is then performed for the identified functions, functional failures, and likely failure modes of each component of the asset. The failure modes can be identified from first principles and historical failure data from the asset owner or databases such as the Offshore Reliability Database (...

Research paper thumbnail of A multi-objective framework for the optimisation of life-cycle costs of wind turbines

Multi-objective optimization of the life-cycle costs and reliability of offshore wind turbines (W... more Multi-objective optimization of the life-cycle costs and reliability of offshore wind turbines (WTs) is an area of immense interest due to the widespread increase in wind power generation across the world. Though there has been significant research done in this field for structures such as bridges and offshore oil and gas platforms, less research has been conducted for the costs and reliability optimization of offshore WTs. Most of the existing studies have addressed the conjunction of structural reliability and the Bayesian preposterior analysis for multi-objective optimization. This paper proposes and extension of the previous approaches as a novel framework for multi-objective probabilistic optimization of the total life-cycle costs and reliability of WTs by combining the elements of structural reliability analysis, Bayesian pre-posterior analysis with neuro-fuzzy and evolutionary algorithms. The output of this framework would determine the optimal inspection, monitoring and main...

Research paper thumbnail of Scheduling structural health monitoring activities for optimizing life-cycle costs and reliability of wind turbines

Smart Materials and Nondestructive Evaluation for Energy Systems 2017, 2017

Optimization of the life-cycle costs and reliability of offshore wind turbines (OWTs) is an area ... more Optimization of the life-cycle costs and reliability of offshore wind turbines (OWTs) is an area of immense interest due to the widespread increase in wind power generation across the world. Most of the existing studies have used structural reliability and the Bayesian pre-posterior analysis for optimization. This paper proposes an extension to the previous approaches in a framework for probabilistic optimization of the total life-cycle costs and reliability of OWTs by combining the elements of structural reliability/risk analysis (SRA), the Bayesian pre-posterior analysis with optimization through a genetic algorithm (GA). The SRA techniques are adopted to compute the probabilities of damage occurrence and failure associated with the deterioration model. The probabilities are used in the decision tree and are updated using the Bayesian analysis. The output of this framework would determine the optimal structural health monitoring and maintenance schedules to be implemented during the life span of OWTs while maintaining a trade-off between the life-cycle costs and risk of the structural failure. Numerical illustrations with a generic deterioration model for one monitoring exercise in the life cycle of a system are demonstrated. Two case scenarios, namely to build initially an expensive and robust or a cheaper but more quickly deteriorating structures and to adopt expensive monitoring system, are presented to aid in the decision-making process.

Research paper thumbnail of Optimization of monitoring and inspections in the life-cycle of wind turbines

Smart Materials and Nondestructive Evaluation for Energy Systems 2016, 2016

The past decade has witnessed a surge in the offshore wind farm developments across the world. Al... more The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

Research paper thumbnail of Reliability-centered maintenance and cost optimization for offshore oil and gas components

Journal of Physics: Conference Series, 2021

Reliability-Centered Maintenance (RCM) is widely used for enterprise asset management in the Oil ... more Reliability-Centered Maintenance (RCM) is widely used for enterprise asset management in the Oil and Gas sector. The traditional RCM process encompasses the development of equipment hierarchy, the determination of the functional failure of assets, identification of the critical failure modes and the development of suitable maintenance strategies for these failure modes through RCM logic tree analysis. However, the current industry standards and conditions call for greater strides of production availability and reliability of the assets. The aim of the paper is to deliver RCM oriented cost optimization framework for the assets through the implementation of probabilistic and statistical analysis. Probabilistic analysis of the most critical components predicts the failure over time. The mean time to failure, mean time between failure and mean time to repair parameters are determined from the failure history. The parameters of the probability distribution, for instance, the shape and sc...