Blar i NTNU Open på forfatter "Nejad, Amir R."
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Comparative analysis of rolling contact fatigue life in a wind turbine pitch bearing with different modeling approaches
Rezaei, Ashkan; Schleich, Florian; Menck, Oliver; Grassmann, Matthis; Bartschat, Arne; Nejad, Amir R. (Journal article; Peer reviewed, 2024)The load calculation for wind turbines usually does not take pitch bearings into account, and the pitch-bearing internal load distribution is calculated in a decoupled process. In the current study, a coupled wind turbine ... -
A comparative study of fully coupled and de-coupled methods on dynamic behaviour of floating wind turbine drivetrains
Wang, Shuaishuai; Moan, Torgeir; Nejad, Amir R. (Peer reviewed; Journal article, 2021)Traditionally, drivetrain responses are obtained by a de-coupled analysis, which first involves a global analysis with a simplified representation of the drivetrain, followed by a detailed analysis of the drivetrain with ... -
Comparison of Extreme Wind and Waves Using Different Statistical Methods in 40 Offshore Wind Energy Lease Areas Worldwide
Bhaskaran, Saravanan; Verma, Amrit Shankar; Goupee, Andrew J.; Bhattacharya, Subhamoy; Nejad, Amir R.; Shi, Wei (Peer reviewed; Journal article, 2023)With the ongoing global drive towards renewable energy, several potential offshore wind energy lease areas worldwide have come into focus. This study aims to estimate the extreme wind and wave conditions across several ... -
Condition Monitoring of Ship Propulsion Systems: State-of-the-Art, Development Trend and Role of Digital Twin
Nejad, Amir R.; Etienne, Purcell; Mostafa, Valavi; Roman, Hudak; Benjamin, Lehmann; Francisco Gutiérrez, Guzmán; Felix, Behrendt; Angelo Mario, Bõhm; Franz, von Bock und Polach; Brendon M., Nickerson; Anriëtte, Bekker; Withold, Drazyk (Chapter, 2021)This paper describes the current implementations and development trends of condition monitoring as it pertains to ship propulsion systems. In terms of total incidents in the shipping industry in the last five years, failures ... -
A data-driven approach for fault diagnosis of drivetrain system in a spar-type floating wind turbine based on the multi-point acceleration measurements
Dibaj, Ali; Nejad, Amir R.; Gao, Zhen (Peer reviewed; Journal article, 2022)This paper deals with the condition monitoring of a floating wind turbine drivetrain using multi-point acceleration measurements. Single sensor data obtained from drivetrain system may provide insufficient information about ... -
Design and Dynamic Analysis of a 10-MV Medium-Speed Drivetrain in Offshore Wind Turbines
Wang, Shuaishuai (Doctoral theses at NTNU;2021:124, Doctoral thesis, 2021)This thesis deals with design and dynamic analysis of 10-MW medium-speed drivetrains for large-scale offshore wind turbines. Many issues related to two main topics, drivetrain design and dynamic analysis, have been ... -
Design and Dynamic Analysis of a Compact 10 MW Medium Speed Gearbox for Offshore Wind Turbines.
Wang, Shuaishuai; Nejad, Amir R.; Moan, Torgeir (Peer reviewed; Journal article, 2021)This paper deals with the design of a compact gearbox for the DTU 10 MW reference offshore wind turbine. An innovative gearbox concept consisting of a fixed planetary stage and a differential compound epicyclic stage is ... -
Development and validation of a coupled aero-hydro-servo-elastic-mechanical model for a 10 MW offshore wind turbine utilizing multi-body simulation software
Monnac, Jean-Mark M. (Master thesis, 2021)This thesis details the development and validation of a fully coupled aero-hydro-servo-elastic-mechanical multi-body simulation (MBS) model with gearbox dynamics for a bottom fixed offshore wind turbine based on a reference ... -
Digital twin based virtual sensor for online fatigue damage monitoring in offshore wind turbine drivetrains
Mehlan, Felix Christian; Nejad, Amir R.; Gao, Zhen (Peer reviewed; Journal article, 2022)In this article a virtual sensor for online load monitoring and subsequent remaining useful life (RUL) assessment of wind turbine gearbox bearings is presented. Utilizing a Digital Twin framework the virtual sensor combines ... -
Digital twin modeling for predictive maintenance of gearboxes in floating offshore wind turbine drivetrains
Khazaeli Moghadam, Farid; de Souza Rebouças, Geraldo Francisco; Nejad, Amir R. (Peer reviewed; Journal article, 2021)This paper presents a multi-degree of freedom torsional model of drivetrain system as the digital twin model for monitoring the remaining useful lifetime of the drivetrain components. An algorithm is proposed for the model ... -
Dynamic Model Development of Wind Turbine Drivetrains by Using Sensor Measurements
van Binsbergen, Diederik; Nejad, Amir R.; Helsen, Jan (Chapter, 2021)This paper aims to analyze the feasibility of establishing a dynamic drivetrain model from condition monitoring measurements. In this study SCADA data and further sensor data is analyzed from a 1.5MW wind turbine, provided ... -
Effect of wind speed distribution and site assessment on pitch bearing loads and life
Rezaei, Ashkan; Nejad, Amir R. (Peer reviewed; Journal article, 2023)In this paper, the wind speed distribution at thirteen onshore and offshore wind sites has been studied. Different probability distributions are used to estimate the wind speed distribution. Several goodness-of-fit indicators ... -
Effects of wind field characteristics on pitch bearing reliability: a case study of 5 MW reference wind turbine at onshore and offshore sites
Rezaei, Ashkan; Guo, Yi; Keller, Jonathan; Nejad, Amir R. (Peer reviewed; Journal article, 2023)This paper presents a study on pitch bearing basic rating life affected by wind field characteristics at both onshore and offshore wind sites. The National Renewable Energy Laboratory 5 MW reference wind turbine is selected ... -
Estimation of Wind Turbine Gearbox Loads for Online Fatigue Monitoring Using Inverse Methods
Mehlan, Felix Christian; Nejad, Amir R.; Gao, Zhen (Chapter, 2021)In this article a novel approach for the estimation of wind turbine gearbox loads with the purpose of online fatigue damage monitoring is presented. The proposed method employs a Digital Twin framework and aims at continuous ... -
Evaluation of PMSG-based drivetrain technologies for 10 MW floating offshore wind turbines: pros and cons in a life-cycle perspective
Khazaeli Moghadam, Farid; Nejad, Amir R. (Peer reviewed; Journal article, 2020)This paper presents an in depth evaluation and comparison of three different drivetrain choices based on permanent‐magnet synchronous generator (PMSG) technology for 10‐MW offshore wind turbines. The life cycle approach ... -
Experimental field study of floater motion effects on a main bearing in a full-scale spar floating wind turbine
Torsvik, Jone; Nejad, Amir R.; Pedersen, Eilif (Peer reviewed; Journal article, 2021)In this paper we present a full-scale experimental field study of the effects of floater motion on a main bearing in a 6 MW turbine on a spar-type floating substructure. Floating wind turbines are necessary to access the ... -
Fault Detection and Diagnosis of Induction Motor for Ship Propulsion by utilizing Electrical Signature and Finite Element Method
Breivik, Andreas (Master thesis, 2021)Induksjonsmotoren studert i denne masteroppgaven er en av to fremdriftsmotorer installert ombord polarforsynings- og forskningsfartøyet SA Agulhaus II og arbeidet er et bidrag til HealthProp-prosjektet (HealthProp 2020). ... -
Fault Detection of Drive Trains in 10 MW Offshore Wind Turbines using Non-Traditional Methods
van der Drift, Maarten Johan Gerben (Master thesis, 2020)One of the world’s biggest concerns is global warming, a solution to this can be wind energy. Offshore wind energy has advantages over onshore wind energy, however, the levelized cost of energy is higher. The maintenance ... -
Fault Detection of Offshore Wind Turbine Drivetrain, State-of-the-Art, Development Trend and Role of Digital Twin
Elmies, Elisa (Master thesis, 2019)Denne masteroppgaven gjennomgår noen av utfordringene vindmøller møter på og hvordan en modellbasert tilstandsovervåking og bruk av en digital tvilling vil være gunstig for lønnsomheten. Avhandlingen viser utviklingen av ... -
Fault Detection of Offshore Wind Turbine Drivetrain. State-of-the-Art, Development Trend and Role of Digital Twin
Elmies, Elisa (Master thesis, 2019)Denne masteroppgaven gjennomgår noen av utfordringene vindmøller møter på og hvordan en modellbasert tilstandsovervåking og bruk av en digital tvilling vil være gunstig for lønnsomheten. Avhandlingen viser utviklingen av ...