Dynamic Response Analysis Research Articles

Power absorption and dynamic response analysis of a hybrid system with a semi-submersible wind turbine and a Salter's duck wave energy converter array

A multi-energy system that integrates a floating offshore wind turbine (FOWT) with wave energy converters (WEC) is an effective way to commercialize new offshore energy and the levelized cost of energy in the future. This paper proposes a FOWT-WEC hybrid system concept consisting of a semi-submersible FOWT with a Salter's duck (SD) WEC array. A coupling framework is established based on OpenFAST and ANSYS-AQWA. A preliminary feasibility study is conducted on the power absorption and motion response of the hybrid system to evaluate the interaction between the SD WEC array and the FOWT. Systematic studies demonstrate that the SD WEC array significantly reduces the motion response of the hybrid system in terms of pitch and heave. An increase in the equilibrium position of the platform in the surge direction does not have a large effect on the stability of the system. The WEC array improves the stability of wind power output and can be used as an effective supplement to power generation. The effect of wave direction shows that the SD WEC has a high sensitivity to the angle of incident waves, and the diffraction and radiation from the platform have a large impact on the power absorption of the SD WEC array.

Dynamic response analysis of high-speed train gearboxes excited by wheel out-of-round: experiment and simulation

Due to the special characteristics of rail vehicles, wheel–rail excitation has always had a huge impact on the stable operation of the vehicle system and the dynamic performance of each component structure. This paper takes high-speed train gearbox as the research object and establishes a rigid-flexible coupling dynamics model and analyses the dynamic response and fatigue damage of the gearbox under the excitation of wheel flat and wheel polygon. Combined with the analysis of test data from the gear transmission testrig and actual line operation of high-speed trains, it shows that high-speed train gearboxes are different from those applied in other fields, where the gear meshing excitation is no longer its main excitation source, but the wheel–rail excitation instead. The comparison analysis between the wheel flat and wheel polygon conditions indicates that the response of the gearbox to the wheel flat excitation is similar to the operational modal test and is capable of causing multi-order modal vibration of the gearbox. The effect of the wheel polygon on the gearbox is similar to that of single-frequency excitation, which lead to certain order modal resonance in the gearbox under frequency coupling situations. The impact of both conditions on gear box fatigue damage increases with the vehicle operating speed.

Analysis of the dynamic response for Kirchhoff plates by the element-free Galerkin method

Dynamic response analysis involves examining structural behavior under dynamic loading conditions. Transient dynamic analysis emerges as a method employed to assess the responses of deformable bodies. Due to the depth analysis of transient responses for thin plates, the associated error analysis work becomes particularly important. In this work, we conduct stability and convergence analysis of the element-free Galerkin (EFG) method for the dynamic response of Kirchhoff plate model. We start by discretizing the thin plate dynamics using the EFG method for the spatial domain and the central difference scheme for the temporal domain. Stability and convergence analysis for transient responses, including deflection and moment responses, are derived similarly to those in two-dimensional transient structural dynamic analysis. The key to the analysis is transforming the governing equations and clamped boundary conditions into a weak formulation with penalty terms using the penalty method. The main results demonstrate a significant correlation between the error estimate and both nodal spacing and time step size. Additionally, the continuity of the approximation functions and the selection of penalty factors significantly affect numerical accuracy. To validate the theoretical results, we conduct numerical experiments involving clamped square and L-shaped plates with uniform and nonuniform node distributions, as well as a perforated plate model. Furthermore, we investigate the impact of node influence domains and penalty factors on numerical accuracy, facilitating parameter selection for practical engineering applications.

KT-Biologics I (KTB1): A dynamic simulation model for continuous biologics manufacturing

The pharmaceutical industry's shift towards biological therapeutics has led to a transition from conventional batch production to continuous manufacturing. This change highlights the crucial need for effective process monitoring and control strategies to ensure consistent product quality and stability. Open-source benchmark simulation models have become essential tools for refining these processes, offering a platform for testing research hypotheses. This study uses the production of Lovastatin as a case study for continuous biopharmaceutical production. A comprehensive dynamic model covering upstream and downstream components provides an integrated perspective of the production process. The study introduces a basic control system emphasizing realistic sensor and actuator integration to enhance simulation accuracy. It assesses the benchmark through open-loop and closed-loop simulations, offering an in-depth analysis of the KTB1 model's dynamic response and functionality. KTB1 represents a model-driven decision support tool that enables the evaluation of monitoring strategies, process design, process optimization, and control for biomanufacturing.

Numerical and experimental investigations on dynamic response of twin-barge floatover system in standby phase

The twin-barge floatover installation method is an efficient method for the mega topsides installation for the offshore platform because of the large capacity and the gap-free for the substructures. This paper develops the dedicated software TBF-TJU (Twin-Barge Floatover by TJU) for dynamic response analysis of the twin-barge floatover installation system. A numerical model of the elastically-connected twin-barge floatover installation system was developed to analyze the coupled dynamic response of topsides and barges. The motion equations of the twin-barge and the topsides with consideration of the mechanical connections and the hydrodynamic interactions are derived and then solved in the time domain. The loads on mating units DSU(Deck Support Unit) in head and beam seas are numerically and experimentally investigated in detail. The numerical results are compared to the results of the corresponding tests in regular and random waves. Time-series and statistical comparisons of the motions and loads indicate that the numerical model can provide a reasonable estimation of the dynamic response of the twin barges and the topsides. The motion of the upwind barge is significantly larger than that of the leeward barge in beam sea due to the shielding effect and the hydrodynamic interactions.

Wind-Induced Response Analysis and Fatigue Reliability Study of a Steel–Concrete Composite Wind Turbine Tower

Taking an actual 3MW steel–concrete composite wind turbine tower as an example, a finite element model of the tower structure was established, and static bearing capacity and dynamic time history response analyses were performed to identify the locations where the structure is prone to failure. On this basis, the fatigue lives of the turbine tower at the most unfavorable locations were predicted using linear cumulative damage theory, and the fatigue reliability at the corresponding locations of the structure was calculated using the kriging–subset simulation method. The most dangerous locations of the tower that are most prone to failure are as follows: the bottom of the leeward side of the upper steel tube, the flange of the steel tube, the bolt-hole imprinting surface of the flange, the leeward side of the transition tube, and the top of the leeward side of the concrete tube. The failure risk of the flange and bolt-hole imprinting surface of the upper steel tube is relatively high, followed by that of the transition tube. This indicates that special attention should be given to the design and daily maintenance of this part. The fatigue resistance of the tower can be enhanced by improving the strength of the flange plate or increasing the number of bolts and strengthening the transition tube.

Dynamic response, durability, and carbon footprint analysis of the marl clay treated with sodium lignosulfonate as a sustainable-environmentally friendly approach

In the current study, the marl clay was improved by different contents of sodium lignosulfonate (NLS) and cured at different times and then, all samples were subjected to Bender Element (BE), Unconfined Compressive Strength (UCS), and Brazilian Tensile Strength (BTS) tests considering two different dry condition (DC) and wet condition (WC). The durability of the samples was further controlled by a special technique, namely the soaking test. The carbon footprint analysis was undertaken for a low-volume trench project to address the sustainability benefits associated with replacing cement and lime as traditional stabilizers with NLS. The results show that the reuse of NLS as a non-traditional alternative for stabilizing marl soil can play an influential role in improving dynamic parameters as well as sustainable development. It has been observed that the CO2 emission decreases up to 5.6 and 4.4 times compared to lime and cement, respectively. Additionally, the use of NLS enhances the UCS by 249%, BTS by 208%, and small strain shear modulus by 117%. Furthermore, reducing the adverse effects of the WC on soil properties, among others, was the main finding of utilizing the NLS in marl stabilization with curing time. NLS-treated marl samples were able to preserve the integrity of their particles even after being soaked in water for a period of 3 weeks. In contrast, the particles of the untreated sample started to disintegrate within a few seconds of initiating the soaking test. Finally, possible equations correlating the dynamic and static moduli were reported in this study.

Nonlinear dynamical modeling and response analysis of complex structures based on assumed mode weighting

The assumed mode method (AMM) is widely used for dynamical modeling but faces increasing challenges in developing low-dimensional and high-precision models of complex structures for investigations of nonlinear dynamical responses and active vibration control. This is mainly because the current complex structure has an increasing number of components, each of which needs to be discretized by multiple assumed modes in dynamical modeling, leading to increasing degrees of freedom for the system. To address this issue, this paper proposes a dimension-reduced method based on the assumed mode weighting method, referred to as Mode Weighting Method (MWM). The modeling process of a multi-beam structure is fully presented as an example to show the strategy of the MWM. During this process, the assumed mode (AM) model (the dynamic model derived in terms of a set of assumed modes) is developed first where the joints of the structure between its components are considered as artificial springs and each component is discretized by its vibration modes without constraints. The components of the eigenvector of the characteristic equation derived from the AM model are taken as the weighting coefficients to get the approximate analytical global modes of the structure by multiplying the corresponding assumed modes. Consequently, a nonlinear dynamic model with a few degree of freedom is obtained by discretizing the structure with the weighted modes. Moreover, a technique for simply obtaining the weighted mode (WM) models by directly processing the AM model through a transformation matrix is presented. To validate the proposed method, the simulations on the natural characteristics and the dynamical responses for both linear and nonlinear models, are performed respectively based on the WM and the finite element models, where both results are well matched each other. This work provides a new way of developing advanced dynamical modeling methods for structural dynamics design, optimization, and active vibration control.

Dynamic Response Analysis of Moving Loads over Tension Cables of Connected Tower Cable-Stayed Bridge

Due to its strong crossing ability, cable-stayed bridges have become the mainstream bridge type for large and medium spans. The connected tower cable-stayed bridge is different from traditional single span cable-stayed bridges, integrating the characteristics of split frame structure and connected tower design, and has better structural mechanical properties. However, the complex cable layout, multi tower structure, and segmented bridge deck of the cable-stayed bridge with connected towers result in essential differences in its mechanical behavior compared to traditional bridges. Therefore, studying the dynamic response of cable-stayed bridge cables when vehicle loads pass through the bridge is of great practical significance. This article comprehensively considers two factors: vehicle weight and vehicle speed, and introduces the parameter of dynamic amplification factor. The numerical simulation method is used to analyze the dynamic response of the cable when a vehicle load passes through a cable-stayed bridge with a connected tower. In order to provide key data support and important references for the construction and operation monitoring of cable-stayed bridges with connected towers.

Numerical Modeling and Dynamic Response Analysis of an End-Anchored Floating Bridge With a Damaged Pontoon Under Repair Operation

Abstract Floating bridges face potential hazards due to ship collisions throughout their operational lifetime. In a situation where a pontoon is significantly damaged from an accident, a floating drydock may be used to compensate for the lost buoyancy and provide a dry atmosphere for operations. As the repair might take months, a primary concern is whether the repair can be in-site conducted without shutting down the road traffic. This study aims to investigate the feasibility of using a drydock for the repair. The numerical model of the in-operation damaged bridge is established for a comparative dynamic analysis with the intact end-anchored bridge. Eigenvalue analysis is conducted, and pendulum modes of oscillation are found with an eigen-period of around 15 s. The dynamic responses are analyzed through a series of fully coupled time-domain simulations under various environmental conditions. The results indicate that the standard deviation of the moment about the girder weak axis increases significantly at the damaged pontoon axis due to the excitation of low-frequency resonant response. Swell wave loads might induce dynamic amplification to the damaged bridge, even with a relatively small wave height. In addition, the internal stress of the bridge girder is investigated and found to be larger, especially, at the lower locations of the cross section. It is suggested that the responses can be managed by limiting the excitation of pendulum modes or providing special damping devices in practical engineering.

Numerical Analysis of Dynamic Response in Large Caissons during Wet-towing after Cable Breakage

Variable and complex marine environmental loads combined with wave resistance and the insufficient controllability of large caisson structures pose serious challenges during maritime towing. Cable breakage events are common, and improper behaviors could give rise to a variety of accidents. This work explored the dynamic responses of large caisson structures following towing cable breakage under irregular waves combined with harsh currents. Two types of cable breakage, i.e., main bridle and towing bridle breakage, were taken into account. Four potential wave–current combinations were assumed for each situation according to direction. The obtained results show that drag rope breakage could give rise to lateral shifts in the structure, which can become a serious condition when exposed to angled waves. Additionally, following breakage, significant force fluctuations took place in the remaining intact cables. For main cable breakage, both lateral and backward displacements were observed in the structure, which gradually entered a ‘flowing with the wave’ state. Furthermore, under the two abovementioned cable breakage conditions, the structure air gap consistently exceeded 2.3 m, ignoring the possibility of a wave slamming event.

Stochastic seismic dynamic response analysis for coupled transmission tower-insulator-line systems considering soil-structure interaction

The conventional seismic analysis and design of transmission tower-insulator-line systems usually ignore the effects of soil-structure interaction (SSI) and the randomness of ground motions, which might lead to an unreasonable estimation of the system's seismic performance. In addressing this issue, this paper proposes two effective simplified models of coupled transmission tower-insulator-line systems considering soil-structure interaction (CTILSs-SSI), for stochastic seismic dynamic response analysis. In these models, the foundation and tower are simulated by single and multiple degree of freedom models, respectively; meanwhile, the insulator is simulated by a single pendulum model, and the effect of SSI is considered using the swing-rocking (S-R) model. Specifically, for the in-plane vibration, the transmission line is simulated by a multiple degree of freedom rigid-bar assemblage with lumped masses; for the out-of-plane vibration, the transmission line is simulated by a multiple pendulum model. On this basis, the equations of motion for CTILSs-SSI under both in-plane and out-of-plane vibrations are derived utilizing the Euler-Lagrange equation. Subsequently, a non-stationary stochastic seismic dynamic response analysis framework for CTILSs-SSI is proposed by incorporating the proposed simplified models with the probability density evolution method (PDEM). An ultra-high voltage (UHV) transmission tower-insulator-line system is taken as an example. The simplified models of this exemplar system are established and validated using ANSYS software. In addition, the deterministic and stochastic seismic dynamic response analyses of this exemplar system are conducted. The analysis results demonstrate that the dynamic response amplitudes of the tower top and the tower's natural periods increase considering the effect of SSI, and the impact of SSI increases as the subsoil softens. Furthermore, the probability density function (PDF) of the tower top displacement of the CTILS-SSI exhibits distinct shapes at various moments. The mean value of the tower top displacement of the CTILS-SSI fluctuates around zero over time, while the standard deviation increases within approximately 0s–10s and then decreases.

An attention-based deep learning method for safety of uncertain vehicle-bridge system with random near fault earthquakes

In this paper, a novel approach, based on the principle of the deep learning method, is proposed to study the stochastic responses of vehicle-bridge system (VBS) subjected to near fault earthquakes (NFEs), which also considers the effects of uncertain parameters. To generate the training data as the input of the proposed deep learning model, the dynamic formulas of the VBS are deduced by Newmark-β method. The proposed analysis model comprises three modules: the CNN module for seismic data feature extraction, the Attention Mechanism module for enhancing the selection for information between time series to improve the accuracy and efficiency of the final prediction, and the Bidirectional Gated Recurrent Unit (BiGRU) for predicting VBS responses. The mapping connection between earthquake action and the system response is established. The BiGRU model is capable of conveying both the excitation's randomness and the system's uncertain parameters. An actual railway cable-stayed bridge subjected to the running railway vehicle and NFEs is utilized to verify the proposed model. The uncertain train weight, bridge damping ratio and the randomness of NFEs are incorporated into the dynamic responses analysis of VBS. As a result, the time-varying responses obtained by the proposed model show significant agreement with results from a validated dynamic VBS framework. The mean value and standard deviation (STD) of the responses obtained by the proposed method are also compared with those by the Monte Carlo method and probability density evolution method. Therefore, both the individual sample of the dynamic response and the statistical data from diverse stochastic responses are chosen to validate the model's accuracy and efficiency in the VBS analysis under NFEs. In addition, the effects of the stochastic characteristics on the system's random vibrations are also explored through the time-histories of statistical data and the probability density function of the absolute maximum of responses.

Random dynamic response analysis of an asphalt concrete core wall dam on deep overburden with double random factors

The spatial variability of material parameters and the randomness of ground motion are factors that influence the seismic response of a dam. To obtain more reliable seismic response results, it is crucial to study the influence of various uncertain factors on the response to earthquakes. In this paper, the K-L series expansion method and LH sampling technique are combined to characterize the spatial correlation of material parameters using a Gaussian autocorrelation function. This allows for the simulation of random fields of material parameters. By improved the Clough-Penzien power spectrum model and incorporating the concept of a random function, it becomes possible to generate nonstationary random ground motion that accurately reflects the site conditions. Taking an asphalt concrete core dam on deep overburden as an example, a random dynamic response analysis was conducted, considering various random factors. Statistical analysis and distribution testing were conducted on the horizontal acceleration and vertical permanent deformation responses. The process of the evolution of the probability density of the horizontal acceleration at the top of the dam was determined using the generalized probability density evolution method. This method helps to reveal the influence of various random factors on the response of the dam body. The research results show that among the spatial variability of material parameters and the randomness of ground motions, the randomness of ground motions is the main influencing factor of the random response results of the dam body. The mean response of two random factors is significantly larger than that of a single random factor. When considering dual random factors simultaneously, the complexity of the random factors increases, resulting in statistical properties that differ from those of single random factors. Therefore, to obtain more reliable random seismic response results, it is necessary to consider both the spatial variability of material parameters and the randomness of ground motions.

Research on noise reduction and data mining techniques for pavement dynamic response signals

Purpose This study aims to ensure reliable analysis of dynamic responses in asphalt pavement structures. It investigates noise reduction and data mining techniques for pavement dynamic response signals. Design/methodology/approach The paper conducts time-frequency analysis on signals of pavement dynamic response initially. It also uses two common noise reduction methods, namely, low-pass filtering and wavelet decomposition reconstruction, to evaluate their effectiveness in reducing noise in these signals. Furthermore, as these signals are generated in response to vehicle loading, they contain a substantial amount of data and are prone to environmental interference, potentially resulting in outliers. Hence, it becomes crucial to extract dynamic strain response features (e.g. peaks and peak intervals) in real-time and efficiently. Findings The study introduces an improved density-based spatial clustering of applications with Noise (DBSCAN) algorithm for identifying outliers in denoised data. The results demonstrate that low-pass filtering is highly effective in reducing noise in pavement dynamic response signals within specified frequency ranges. The improved DBSCAN algorithm effectively identifies outliers in these signals through testing. Furthermore, the peak detection process, using the enhanced findpeaks function, consistently achieves excellent performance in identifying peak values, even when complex multi-axle heavy-duty truck strain signals are present. Originality/value The authors identified a suitable frequency domain range for low-pass filtering in asphalt road dynamic response signals, revealing minimal amplitude loss and effective strain information reflection between road layers. Furthermore, the authors introduced the DBSCAN-based anomaly data detection method and enhancements to the Matlab findpeaks function, enabling the detection of anomalies in road sensor data and automated peak identification.

Rapid dynamic aeroelastic response analysis of the highly flexible wing with distributed propellers influence

Abstract A rapid nonlinear aeroelastic framework for the analysis of the highly flexible wing with distributed propellers is presented, validated and applied to investigate the propeller effects on the wing dynamic response and aeroelastic stability. In the framework, nonlinear beam elements based on the co-rotational method are applied for the large-deformation wing structure, and an efficient cylinder coordinate generation method is proposed for attached propellers at different position. By taking advantage of the relatively slow dynamics of the high-aspect-ratio wing, propeller wake is modeled as a quasi-steady skewed vortex cylinder with no updating process to reduce the high computational cost. Axial and tangential induced velocities are derived and included in the unsteady vortex lattice method. For the numerical cases explored, results indicate that large deformation causes thrust to produce wing negative torsion which limits the displacement oscillation, and slipstream mainly increases the response values. In addition, an improvement of flutter boundary is found with the increase of propeller thrust while slipstream brings a destabilising effect as a result of the increment of dynamic pressure and local lift. The great potential of distributed propellers in gust alleviation and flutter suppression of such aircraft is pointed out and the method as well as conclusions in this paper can provide further guidance.

Numerical Simulation of a Submerged Floating Tunnel: Validation and Analysis

The dynamic response analysis of submerged floating tunnels (SFTs) under seismic action is a complex two-way fluid–structure coupling problem that requires expertise in structural dynamics, fluid mechanics, and advanced computational methods. The coupled Eulerian–Lagrangian (CEL) method is a promising method for solving fluid–structure interaction problems, but its application to SFTs is not well established. Therefore, it is crucial to verify the accuracy and reliability of the CEL method in fluid–structure coupling simulations. This study verified the applicability of the CEL method for simulating one-way and two-way fluid–structure coupling cylindrical flow problems, and then applied the CEL method for the analysis of a shaking table test of a model SFT. A comparison of results obtained with the CEL method with those obtained in a previous indoor model test of an SFT demonstrates the agreement between the results of the CEL method and the overall trend of the experimental results, indicating the reliability of the method for the seismic analysis of SFTs. Moreover, the analysis of the dynamic response characteristics of SFTs under seismic conditions provides data support and a technological means for the seismic design of SFTs.

A Machine Learning Model to Predict the Seismic Lifecycle Behavior of a Cross-Sea Cable-Stayed Bridge

Cross-sea cable-stayed bridges encounter challenges associated with cable corrosion and cable-force relaxation during their service life, which significantly affects their structural performance and seismic response. This study focuses on a cross-sea cable-stayed bridge located in Hainan Province. Utilizing an LSTM deep learning model, this study aims to fill in the gaps in short-term cable-monitoring data from the past year using the available cable-force-monitoring data from the same period. The authors of this study interpolated the cable-force data in the absence of sensors and employed a SARIMA machine learning time-series-prediction model to predict the future trends of all cable forces. A finite-element model was constructed, and a dynamic time-history analysis of the seismic response of the cross-sea cable-stayed bridge was conducted, considering the influence of cable-force relaxation and cable corrosion in the future. The findings indicate that the LSTM-SARIMA model predicted an average decrease of 11.81% in the cable force of the cable-stayed bridge after 20 years. During the lifecycle of the cables, cable corrosion exerts a significant impact on the variation in cable stress within the bridge structure during earthquakes, while cable-force relaxation has a more pronounced effect on the vertical displacement of the main beam of the bridge structure during seismic events. Compared to when using the traditional model that only considers cable corrosion, the maximum negative vertical displacement of the main beam increases by 29.7% when using the proposed model if the earthquake intensity is 0.35 g after 20 years, which indicates that the proposed machine learning model can exactly determine the seismic behavior of the lifecycle cross-sea cable-stayed bridge, considering the impacts of both cable-force relaxation and cable corrosion.

Study on the coupling calculation method for the launch dynamics of a self-propelled artillery multibody system considering engraving process

The launch dynamics theory for multibody systems emerges as an innovative and efficacious approach for the study of launch dynamics, capable of addressing the challenges of complex modeling, diminished computational efficiency, and imprecise analyses of system dynamic responses found in the dynamics research of intricate multi-rigid-flexible body systems, such as self-propelled artillery. This advancement aims to enhance the firing accuracy and launch safety of self-propelled artillery. Recognizing the shortfall of overlooking the band engraving process in existing theories, this study introduces a novel coupling calculation methodology for the launch dynamics of a self-propelled artillery multibody system. This method leverages the ABAQUS subroutine interface VUAMP to compute the dynamic response of the projectile and barrel during the launch process of large-caliber self-propelled artillery. Additionally, it examines the changes in projectile resistance and band deformation in relation to projectile motion throughout the band engraving process. Comparative analysis of the computational outcomes with experimental data evidences that the proposed method offers a more precise depiction of the launch process of self-propelled artillery, thereby enhancing the accuracy of launch dynamics calculations for self-propelled artillery.

Dynamic response analysis of a semisubmersible floating offshore wind turbine subjected to mooring line failure under normal and extreme environmental conditions

Floating offshore wind turbines (FOWTs) offer a significant opportunity for harnessing wind energy and achieving clean energy goals. This paper investigates the effects of mooring line failure in semisubmersible FOWTs under normal and extreme environmental conditions. The OC4 DeepCwind type semisubmersible with an NREL 5 MW wind turbine is considered for investigating the behavior of FOWT under intact and failed mooring lines. This study covers a wide range of environmental conditions, operational conditions of wind turbines, and mooring line failure scenarios. This paper investigates the mooring line failure effects on platform responses, mooring line fairlead tensions, and tower responses. The results show that the platform surge, heave, pitch responses, tower fore-aft displacement, base shear force in X-direction, and base moment in Y-direction are increased for upwind side mooring line failure during the operational condition of FOWT. Subsequently, the platform sway, roll, yaw responses, tower side-to-side displacement, base shear force in Y-direction, and base moment in X-direction are more during downwind side mooring line failure in the same environment. On the other hand, the impact of upwind side mooring line failure affects all 6 Degrees of Freedom (DOF) platform responses significantly during the parked state of FOWT. The maximum fairlead tensions observed in the remaining mooring lines remain below the mooring line breaking strength even after a mooring line failure during both operational and parked states of FOWT. It is also observed that the platform responses (excluding heave), tower responses, and fairlead tensions exhibit greater values when an extreme turbulence wind model is employed. The platform surge, heave, pitch responses, maximum fairlead tension, tower fore-aft displacement, and tower base moment in Y-direction show higher values under severe sea state condition.