Blar i NTNU Open på forfatter "Rasekhi Nejad, Amir"
-
A prognostic method for fault detection in wind turbine drivetrains
Rasekhi Nejad, Amir; Odgaard, Peter Fogh; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2014)In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to ... -
A Systematic Design Approach of Gripper’s Hydraulic System Utilized in Offshore Wind Turbine Monopile Installation
Rasekhi Nejad, Amir; Li, Lin; Guachamin Acero, Wilson Ivan; Moan, Torgeir (Chapter, 2018)This paper presents a systematic approach for designing the hydraulic mechanism as a part of the gripper system employed in offshore wind turbine monopile installation. Traditionally, such equipments used in marine operation ... -
A comparative study on the dynamic behaviour of 10 MW conventional and compact gearboxes for offshore wind turbines
Wang, Shuaishuai; Rasekhi Nejad, Amir; Bachynski, Erin Elizabeth; Moan, Torgeir (Peer reviewed; Journal article, 2020)This study compares the dynamic behaviour of a conventional and a compact gearbox for the DTU 10 MW wind turbine supported on a monopile offshore structure. The conventional gearbox configuration is composed of two planetary ... -
Consequences of load mitigation control strategies for a floating wind turbine
Lee, Chern Fong; Bachynski, Erin Elizabeth; Rasekhi Nejad, Amir (Peer reviewed; Journal article, 2020)Several approaches to avoid control-induced resonances of floating wind turbines have been proposed. The main focus has been on reductions in global motions and loads in the tower base. In the present work, we examine the ... -
Correlation between Acceleration and Drivetrain Load Effects for Monopile Offshore Wind Turbines
Rasekhi Nejad, Amir; Bachynski, Erin Elizabeth; Li, Lin; Moan, Torgeir (Journal article; Peer reviewed, 2016)This paper investigates the correlation between the tower-top axial acceleration and the load effects in drivetrain components in a monopile (bottom-fixed) offshore wind turbine. In designing offshore wind turbines, it is ... -
Development of a 5 MW reference gearbox for offshore wind turbines
Rasekhi Nejad, Amir; Guo, Yi; Gao, Zhen; Moan, Torgeir (Journal article, 2016)This paper presents detailed descriptions, modeling parameters and technical data of a 5MW high-speed gearbox developed for the National Renewable Energy Laboratory offshore 5MW baseline wind turbine. The main aim of this ... -
Drivetrain load effects in a 5-MW bottom-fixed wind turbine under blade-pitch fault condition and emergency shutdown
Rasekhi Nejad, Amir; Jiang, Zhiyu; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2016)In this paper, the effect of the blade-pitch fault and emergency shutdown on drivetrain responses in a 5-MW bottom-fixed wind turbine are investigated. A 5-MW reference gearbox with 4-point support is employed and the ... -
Effects of bedplate flexibility on drivetrain dynamics: Case study of a 10 MW spar type floating wind turbine
Wang, Shuaishuai; Rasekhi Nejad, Amir; Bachynski, Erin Elizabeth; Moan, Torgeir (Peer reviewed; Journal article, 2020)This paper deals with the effect of bedplate flexibility on drivetrain dynamics of a 10 MW spar type floating wind turbine. The 10 MW drivetrain bedplate is designed based on extreme design loads and ultimate limit state ... -
Effects of floating sun gear in a wind turbine’s planetary gearbox with geometrical imperfections
Rasekhi Nejad, Amir; Xing, Yihan; Guo, Yi; Keller, Jonathan; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2015)This paper addresses the effect of gear geometrical errors in wind turbine planetary gearboxes with a floating sun gear. Numerical simulations and experiments are employed throughout the study. A National Renewable Energy ... -
Effects of induction and wake steering control on power and drivetrain responses for 10 MW floating wind turbines in a wind farm
van Binsbergen, Dirk Willem; Wang, Shuaishuai; Rasekhi Nejad, Amir (Peer reviewed; Journal article, 2020)This paper aims to investigate the drivetrain load response caused by induction and wake steering control on two floating wind turbines (FWTs) in a wind farm. In this study, two DTU 10 MW turbines, supported on the nautilus ... -
Experimental Validation of Angular Velocity Measurements for Wind Turbines Drivetrain Condition Monitoring
Khazaeli Moghadam, Farid; Rasekhi Nejad, Amir (Chapter, 2019)Drivetrain bearings are seen as the most common reason of the wind turbine drivetrain system failures and the consequent downtimes. In this study, the angular velocity error function is used for the condition monitoring ... -
Fatigue Damage Comparison of Mechanical Components in a Land-based and a Spar Floating Wind Turbine
Rasekhi Nejad, Amir; Bachynski, Erin Elizabeth; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2015)This paper investigates the fatigue damage of the gears and bearings in a land-based and a spar-type floating wind turbine. The reference 5 MW NOWITECH gearbox is used on a land-based and a floating spar wind turbine. ... -
Fatigue Reliability-Based Inspection and Maintenance Planning of Gearbox Components in Wind Turbine Drivetrains
Rasekhi Nejad, Amir; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2014)This paper introduces a reliability-based maintenance plan for wind turbine gearbox components. The gears and bearings are graded based on their fatigue damage and a maintenance map is developed to focus on those components ... -
Frequency based Wind Turbine Gearbox Fault Detection applied to a 750 kW Wind Turbine
Odgaard, Peter Fogh; Rasekhi Nejad, Amir (Journal article, 2014)Reliability and availability of modern wind turbines are of increasing importance, for two reasons. The first is due to the fact that power grids around in the world depends at a higher and higher degree on wind energy, ... -
Learning from non-failure of Onagawa nuclear power station: an accident investigation over its life cycle
Ibrion, Mihaela; Paltrinieri, Nicola; Rasekhi Nejad, Amir (Peer reviewed; Journal article, 2020)This article investigates the successful survival of the Onagawa nuclear power station during and after the 2011 Tohoku earthquake and tsunami. As a research method, a system approach investigation and analysis— CAST (Causal ... -
Long-term Analysis of Gear Loads in Fixed Offshore Wind Turbines Considering Ultimate Operational Loadings
Rasekhi Nejad, Amir; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2013)The long-term extreme value analysis of gear transmitted load due to the main shaft torque is presented. Two methods, the multibody simulations (MBS) and a simplified method, are demonstrated for the gear transmitted load ... -
Numerical modeling of the hydraulic blade pitch actuator in a spar‐type floating wind turbine considering fault conditions and their effects on global dynamic responses
Cho, Seongpil; Bachynski, Erin Elizabeth; Rasekhi Nejad, Amir; Gao, Zhen; Moan, Torgeir (Peer reviewed; Journal article, 2020)This paper deals with numerical modeling of the hydraulic blade pitch actuator and its effect on the dynamic responses of a floating spar‐type wind turbine under valve fault conditions. A spar‐type floating wind turbine ... -
On Design and Analysis of a Drivetrain Test Rig for Wind Turbine Health Monitoring
Balestra, Lorenzo; Rasekhi Nejad, Amir; Naldi, Giovanni (Chapter, 2019)The reliability of offshore wind turbines is a key factor when estimating maintanence costs, downtime due to component failure and overall efficiency during operational life. Offshore wind turbines have limited accessibility ... -
On design, modelling, and analysis of a 10‐MW medium‐speed drivetrain for offshore wind turbines
Wang, Shuaishuai; Rasekhi Nejad, Amir; Moan, Torgeir (Peer reviewed; Journal article, 2020)Utformingen av et drivverk med middels hastighet for 10-MW referanse offshore vindturbin for Danmarks Tekniske Universitet (DTU). Det foreslås en fire-punkts drivlinjeoppsett som er utstyrt med en girkasse med to planetrinn ... -
On Digital Twin Condition Monitoring Approach for Drivetrains in Marine Applications
Johansen, Sigrid S.; Rasekhi Nejad, Amir (Chapter, 2019)A digital twin is a virtual representation of a system containing all information available on site. This paper presents condition monitoring of drivetrains in marine power transmission systems through digital twin approach. ...