Vortex-induced Vibration Amplitude Research Articles

Experimental and numerical study on vibration response, VIV mechanism and aerostatic coefficients of triple-separated decks under different vertical distances

In this study, aerodynamic interference effects (AIE) on the vibration response, aerostatic coefficient (AC) and vortex-induced vibration (VIV) mechanism of the triple-separated decks under different incoming wind directions and vertical distances were investigated via wind tunnel tests and numerical simulations, respectively. The test results show that the AIE increases the displacement of VIV, and the VIV responses reaches maximum value under S/H = −1.0 (S is the vertical distance between the centers of RB and HB decks, and H is the height of RB deck) when the RB deck is on the windward side (the maximum displacements of VIV are 193.86% and 37.30% higher than the case of single RB deck and S/H = 0.0, respectively). The pressure distribution and flow structure show that the scale of vortex that alternately shed off from the tail of the deck becomes stronger and the fluctuating pressure coefficient increases under AIE, which increase the VIV amplitude of the RB deck and cause the VIV of HB decks. The experimental and numerical results indicated that the aerostatic coefficients (AC) of the leeward girder are more affected by the AIE. The interference factor (IF) of drag coefficient (CD) is far less than 1.0 under the case of F-5 (S/H = 0.0).

Vortex-induced vibration dynamic characteristics monitoring with AI-based target object detection for long-span bridges

This research proposes an innovative framework for monitoring bridge Vortex-induced Vibration (VIV) dynamic characteristics utilizing AI-based machine-learning target object detection and tracking techniques with keypoint detection. Two camera calibration methods are implemented for cases with and without intrinsic and extrinsic camera setup information based on homography matrix conversion and distance-based conversion. The framework is verified on a video recording of a real-bridge VIV event and a simulation animation of bridge VIV with a peak/trough-based statistical method for calculating VIV frequency and amplitude. Accurate detection is achieved in both cases with short video durations. The framework demonstrates great potential for real-time bridge VIV monitoring, requiring minimal camera calibration and a straightforward device setup. It offers reliable and accurate results while remaining cost-effective.

Effects of vertical and lateral riser-soil interactions on vortex-induced vibration of a steel catenary riser

A numerical model for computing the vortex-induced vibration (VIV) and fatigue damage of steel catenary risers (SCRs) was developed. The structural dynamics were accurately simulated using an absolute nodal coordinate formulation (ANCF). The Van der Pol wake oscillator is applied to generate the fluctuating lift, which is further transformed into the cross-flow direction by considering the structural deformation. The Randolph-Quiggin (RQ) model and the Coulomb friction ‘bilinear’ model are employed to simulate the vertical and lateral riser-soil interactions, respectively. After case validations, the effects of riser-soil interaction on the VIV amplitude, frequency, mode, and fatigue of the SCR at different current angles are investigated, and a sensitivity study of different seabed model parameters is discussed. The bands of significant VIV frequencies were broadened by riser-soil interactions, accompanied by more frequency components of disturbance and more abundant vibration modes. Severe fatigue damage cannot be captured by the truncated model, and seabed models that require improvement are ignored. It is suggested that vertical and lateral riser-soil interactions should be considered in the evaluation of VIV fatigue damage for SCRs.

Experimental study of wind-field characteristics and torsional vortex-induced vibrations for a split three-box deck sitting above water waves

The wind-field characteristics of a split three-box deck sitting above water waves and its torsional vortex-induced vibrations (VIVs) were experimentally investigated using wind-tunnel and wave-flume tests. The wind field was measured using turbulent flow instrumentation (TFI) Cobra probe. To test the VIVs of the split three-box deck, a test system that could elastically suspend the deck sectional model by eight springs and guarantee free oscillation of the deck sectional model only in the heaving and torsional directions was constructed. The test results indicated that the regular wave height (H) and regular wave period (T) mainly promoted the overall turbulence-intensity (Iuvw) and turbulence-intensity component (Iw). These contributions were further strengthened by an increase in H and a decrease in T, respectively. In general, the variations in Iuvw and Iw, particularly the latter, should be regarded as the major cause of the change in the maximum torsional VIV amplitudes of the deck sectional model with a scale ratio of 1:60 when compared to the mean local wind speed (U) and wind-speed component (w). The differences in these amplitudes under different cases in the first lock-in regions were not evident, whereas those in the second lock-in regions were significant. In the second regions, the smaller the relative bridge clearance (a/H), the smaller the maximum torsional VIV amplitudes, and the maximum torsional VIV amplitudes increased with T, which were all smaller than those in the corresponding wind-only case. Moreover, the larger the bridge clearance (a), the larger the maximum torsional VIV amplitudes in the wind-only cases (a = 0.30, 0.42, 0.50, and 0.58 m). Evidently, the presence of water waves is conducive to the suppression of torsional VIVs of the split three-box deck when VIVs occur.

Machine learning models for predicting VIV amplitude of streamlined steel box girders

The vortex-induced vibrations (VIVs) can cause severe consequences for long-span bridges, including structural fatigue, human-body comfort and vehicle safety, and become significant issues in terms of the wind-resistance. Currently, estimations of VIV amplitudes are typically based on wind tunnel tests, field monitoring, computational fluid dynamics and theoretical models. In this paper, a machine learning (ML) approach is developed for rapidly estimating the VIV amplitude of a streamlined steel box girder during preliminary structural design. The VIV amplitude forecasting models are constructed using four well-established and widely used ML algorithms, e.g., support vector machine (SVM), random forest (RF), gradient boosting decision tree (GBDT), and artificial neural network (ANN). These four models take geometric and dynamic features as inputs, and output the VIV amplitude. The hyper-parameters are optimized to attain acceptable accuracy. To address the low interpretability of complex ML models, this paper introduces the Shapley additive explanations (SHAP) method to explain the VIV prediction pattern. The results indicate that the constructed ML models with optimal hyper-parameters show excellent performance for predicting the VIV amplitude in a validated and accurate manner. The SHAP explanation supports these results and offers valuable additional insights.

Study on mechanism of VIV causing limited amplitude vibration through LES for a 4:1 rectangular cylinder

Vortex-induced vibration (VIV) is characterized as a phenomenon of limited amplitude vibration. Understanding the basic nature and underlying mechanism of VIV is necessary for predicting the vibration amplitude. In this study, using Large Eddy Simulation (LES) of forced vibration, a detailed investigation of the flow pattern and wind load during VIV of a 4:1 rectangular cylinder is conducted. The results indicate that both vibration amplitude (y0/D) and wind speed (UR) significantly influence the flow pattern and wind load. Notably, an increase in vibration amplitude leads to a predominance of motion-induced force and a corresponding amplification of the fluctuating lift coefficient. Additionally, a decrease in the phase difference between lift force and displacement is observed, establishing this phase difference as a critical parameter for predicting vibration amplitude. Regarding wind speed, it is observed that as UR increases, the predominance of motion-induced force diminishes, resulting in a concurrent decrease in the fluctuating lift coefficient. Upon further investigation into the work performed by various forces within a single vibration cycle, it has been determined that as the vibration amplitude escalates, the work of the lift force (energy input WI) initially increases, then diminishes, whereas the work of the damping force (energy dissipation WO) continuously rises. The intersection of these two trajectories signifies the point of energy equilibrium between input and output, thereby establishing the vibration amplitude of VIV. The predicted vibration amplitudes, grounded in this principle, have been corroborated by experimental results.

A Simplified Approach to Recognize Vortex-Induced Vibration Response Using Machine Learning

The vortex-induced vibration (VIV) problem has been of critical concern for the wind-resistance of long-span bridges. Usually there are four types of approach for VIV studies: wind tunnel tests, field monitoring, computational fluid dynamics and mathematical models. However, traditional approaches have shown some limitations, such as high cost and low efficiency. In order to improve the efficiency and accuracy of VIV studies, this article has taken the VIV problem of a split three-box girder in a cable-stayed and cooperative suspension system bridge as an instance, and conducted a series of VIV wind tunnel tests. An approach based on machine learning is described that is able to serve as a complement to the wind tunnel tests. The proposed approach involves two steps: firstly, based on the dataset produced by wind tunnel tests, a clustering algorithm is introduced to separate the VIV signals automatically from other vibrations. Then, an artificial neural network is utilized to recognize the VIV response and aerodynamic force in the lock-in region directly. It is shown that the clustering algorithm can be a good tool for the recognition of VIV signals. Moreover, the proposed artificial neural network models show good ability for recognizing VIV amplitude and aerodynamic lift force.

Response Characteristics and Suppression of Vortex-Induced Vibration of the Flexible Cable

To investigate the vortex-induced vibration (VIV) of a flexible cable in the uniform flow, experiments were conducted using a flexible cable with an external diameter of 80[Formula: see text]mm and a length of 10.48[Formula: see text]m in the wind tunnel. The characteristics of multi-modal VIV, time-frequency and traveling wave behavior of the flexible cable were analyzed. Moreover, the effects of twist direction, diameter and the single/double helical wire on the VIV characteristics of the flexible cable were investigated. It is found that the flexible cable experiences single and multi-modal VIVs in uniform flow at different incoming wind speeds, respectively. For the multi-modal VIV of the flexible cable, the vibration over the time history is dominated by two adjacent modal frequencies and shows a phenomenon of beat vibration. The multi-modal VIV responses of the flexible cable show a mix of standing and traveling wave behaviors, in which the effects of standing wave are more pronounced near both ends and the effects of traveling wave are more dominant in the middle region of the flexible cable. The twist direction of the helical wire has little effect on the VIV responses of the flexible cable. The VIV amplitudes of the flexible cable can be reduced by a single helical wire. With the diameter of the helical wire increases, the suppression effects of the single or double helical wire on the VIV of the flexible cable can be improved. Particularly, the double helical wire with diameter 0.10D can effectively suppress the VIV of the flexible cable.

Influence of non-uniform grid plates on the vortex-induced vibration performance of twin-box girder section

The wind resistance design of long-span bridges necessitates addressing the issue of vortex-induced vibration (VIV) and implementing appropriate counter measures to mitigate it. The present study focused on the examination and comprehensive analysis of a self-anchored suspension bridge. Wind tunnel tests were conducted on sectional models to analyze the effect of wind attack angles on the VIV performance of the girder. Moreover, the investigation examined the impact of opening slot ratio and the configuration of grid plates on the trigger mechanism and performance of VIV. From the results, it is observed that the main girder displays vertical VIV when the damping ratio reaches 0.25%. At wind attack angle of − 3°, 0°, and + 3°, the dimensionless maximum amplitude of the vertical VIV normalized by the height of the girder section, represented as ymax/D, is measured to be 0.032, 0.033, and 0.023 correspondingly. When the opening slot ratio of the grid plates reaches 50%, and the grid plates are non-uniformly arranged on the opening slot, that is the sides of the opening slot position, the vertical VIV becomes non-existent. Furthermore, it is observed that when the grid plates are arranged uniformly with the same opening slot ratio, the suppression effect on VIV is relatively worse and the dimensionless maximum amplitude of the vertical VIV is reduced to 0.013 from 0.032. The flow structure mechanism is that the upside airflow is separated at the windward edge of the girder section, leading to the formation of a large upper vortex. The upper vortices interact with the airflow passing through the upper and lower portions of the central slot, colliding with the top and bottom surfaces of the downstream section. Eventually, the vortices are shifted towards the tail side of the girder section and eventually shed, causing VIV. After implementing grid plates, vortices with a certain size still form at the gap. The grid plate effectively separates the vortices from the upper and lower sections of the girder, reducing their impact on the downstream section and optimizing the VIV performance of the main girder. These research findings could serve as a guide for designing the two-box girder section.

Simultaneous energy utilization and vibration suppression study of a rolling-structured triboelectric nanogenerator for the vortex-induced vibration of a cylinder

Vortex-induced vibration (VIV) is a prevalent phenomenon observed in marine submersible buoys subjected to ocean currents, significantly compromising the structural fatigue life and sensor stability. Meanwhile, the provision of in-situ energy supply and long-term sustainability pose significant challenges for marine submersible buoys. To tackle these issues, this paper presents a novel approach that entails the simultaneous utilization of VIV energy and suppression of VIV through the implementation of a rolling-structured, freestanding triboelectric-layer-based nano-generator (RF-TENG). An experimental investigation has been conducted to explore the power generation mechanism of RF-TENG when subjected to VIV excitation, as well as the vibration suppression effect of RF-TENG on VIV. The following conclusions have been drawn: (1) The maximum power generation is observed within the filling rate range of 50%–60%, where the conversion of kinetic energy to electrical energy resulting from particle friction prevails. Correspondingly, the maximum vibration suppression rate is achieved within the filling rate range of 60%–90%, primarily attributed to energy dissipation due to particle collisions. Notably, at approximately 60%–70% filling rate, RF-TENG exhibits a relatively efficient and balanced performance in terms of both energy utilization and vibration suppression. (2) Particle motion irregularity is a prominent factor that greatly influences the power conversion efficiency, which is manifested as the presence of the third harmonic component in the output voltage and current. The power conversion efficiency of RF-TENG attains its peak value at a filling rate of 50%. (3) Within a certain range, an increase in particle diameter contributes to enhancing the robustness and VIV suppression efficiency of RF-TENG. However, it comes at the cost of reduced power generation capacity. In this study, under the excitation of VIV experienced by a cylinder with an effective amplitude of approximately 1.56 cm and a frequency of approximately 1.62 Hz, RF-TENG achieves a power generation density of 80 mW/m3 and a VIV amplitude suppression rate of 24%. These results suggest that RF-TENG is an effective method for synchronously collecting energy and suppressing VIV in marine structures.

Experimental studied on suppressing vortex-induced vibration of closed-box girder bridges with various moveable guide vanes

A new moveable guide vane with the combination of the spring and guide vane was proposed to suppress the vortex-induced vibration (VIV) of closed-box girder bridges. This paper studies the influence of two important parameters (i.e., horizonal length and spring stiffness) of a moveable guide vane on controlling the VIV of a super long-span suspension bridge with closed-box girder by using VIV control tests. The VIV test of 1:50 scaled ratio of sectional model of the original closed-box girder under three wind attack angles were firstly conducted. The suppression ratios of vertical and torsional VIV displacements of the closed-box girder as well as the movement characteristics of moveable guide vane were then analyzed, respectively. The results show that the movable guide vane could significantly reduced the Root Mean Square (RMS) values of VIV displacement of the closed-box girder are after installing, especial for the torsional VIV displacement. A moveable guide vane with a relative smaller horizontal lengths or a relative larger spring stiffness could produce a better outcome of VIV control. The double VIV amplitude of the moveable guide vanes results in the energy dissipation of the closed-box girder in the lock-in VIV wind speed region, while the vertical displcement of the moveable guide vane are close to those of the closed-box girder in non-VIV wind speed region. Besides, the nonlinear exponential fitting function could effectively reflect the relationship among the wind speed, the VIV displacement of the MGV and the closed-box girder.

Improving the aerodynamic performance of Trans-Tokyo Bay Bridge using reliability-based design optimization

ABSTRACT The Vortex-Induced Vibration (VIV) phenomenon can cause fatigue damage. Usually, countermeasures are implemented to mitigate the VIV amplitudes. However, its cost is high. Therefore, approaches have been developed to avoid VIV at an early stage of design. Most such studies have focused on avoiding the coincidence of the vortex shedding frequency with the natural frequency of the structure and delaying VIVs by including geometrical changes to the leading and trailing edges in order to divide the oncoming flow. In this study, a new framework is proposed to find the optimal deck cross-sectional shape of Trans-Tokyo Bay Bridge, based on Reliability-Based Design Optimization (RBDO) and aiming to mitigate the VIV effects under uncertainty. Validation of the optimal designs is conducted via Computational Fluid Dynamics (CFD) simulations for different target reliability indices.

Modulation and hysteresis in vortex-induced vibration of a spring-mounted cylinder in a slowly varying oscillatory stream

The response of a spring-mounted circular cylinder constrained to vibrate with a single degree of freedom transverse to an oscillating stream is investigated using two-dimensional flow simulations. The Keulegan–Carpenter number was set at large values with the ratio of the oscillatory flow frequency fo to the natural frequency of the cylinder fn assuming values of fo/fn=0.01, 0.02, and 0.04, so as to investigate the effect of very-slowly-varying reduced velocity on the transient response. A maximum reduced velocity of 5, corresponding to a maximum Reynolds number of 150, was employed in all cases. Under these conditions, the cylinder underwent intermittent vortex-induced vibration (VIV) with amplitude modulations at the period of the oscillatory flow. Maximum VIV amplitudes of approximately half diameter occurred near the end of the flow acceleration stage. Pronounced hysteresis was observed in the plots of the ensemble-averaged amplitude and frequency, both being greater during the deceleration stage than during the acceleration stage at the same instantaneous reduced velocity over a significant part of the flow half period. The hysteresis was found to be related to ‘transient’ operating points that, in the space of normalized amplitude and frequency, join smoothly the distinct branches of steady-VIV where operating points do not exist (for the same system with varying the reduced velocity). The main deterministic VIV features were similar at all three frequency ratios examined but the stochastic features became more pronounced as fo/fn was increased. We also found that the cylinder motion and the driving fluid force sometimes were not synchronized around the point of maximum flow velocity, although this point corresponds to well within the synchronization range in steady-VIV.

Effects of superhydrophobicity on VIV control of a circular cylinder

We conducted an experimental study on the vortex-induced vibration (VIV) dynamics of cylinders featuring a specific superhydrophobic band. The superhydrophobic band refers to the pattern where the cylinder's surface is featured with equispaced bands of normal surface and superhydrophobic coating in an alternate manner. The experiments were conducted over a range of reduced velocities from Ur = 3 to 11, corresponding to Reynolds numbers between 1500 and 5900. To capture the near-field wake of the cylinders, a time-resolved particle image velocimetry (TR-PIV) system was employed, while the hydrodynamic forces were acquired using a six-component load cell. We found that the fully coated cylinder consistently displays the smallest amplitude of oscillation in the VIV initial branch, achieving a maximum reduction of approximately 38.9% at Ur = 5.0. Upon applying a superhydrophobic coated band, the patterned cylinder experiences a substantial enhancement in VIV amplitude (about 22.5% at Ur = 5.0) compared to the normal cylinder. On the other hand, in the VIV lower branch, the patterned cylinder effectively suppresses oscillation, whereas the fully coated cylinder exhibits slightly larger oscillation amplitudes than the normal cylinder. This finding agrees well with the trend of lift forces. The analysis of phase-averaged flow structures suggests that this difference can be attributed to the delayed vortex shedding from the superhydrophobic surface and the emergence of three-dimensional vortex structures created by the superhydrophobic band.

Investigations on lock-in vortex-induced vibration of an airfoil at a high angle of attack based on detached eddy simulation

Large-scale modern wind turbines at standstill are prone to vortex-induced vibration (VIV). In this study, coupled fluid–solid dynamics of the wind turbine airfoil at a 90° attack angle are performed using the detached eddy simulation. The fully developed vibration responses with different structural dampings are explored in detail. The frequency lock-in regime is determined, and the corresponding phase differences between the lift and displacement are presented with the Lissajous curve. The dominant surface pressure mode and wake flow exhibit significant three-dimensional flow characteristics in unlock-in conditions, while a strong spanwise correlation in lock-in conditions is detected. The pressure fluctuation on the suction side in the lock-in state is observed to be more significant than in the unlock-in state. The effect of the distributed airfoil surface pressure on VIV is evaluated by considering the contribution value and the cyclic aerodynamic work density. With the decrease in structural damping, the aerodynamic work near the leading edge gets enhanced and the negative work region is reduced, leading to a higher amplitude of VIV. The beat vibration and hysteresis behavior at the critical reduced velocity are also analyzed in both the time domain and frequency domain.

Research on Mechanism of Vortex-Induced Vibration Railing Effect of Double-Deck Large-Span Suspension Bridge

Large-span suspension bridges are susceptible to wind loads. Therefore, a more precise analysis of their wind-induced vibration response is necessary to ensure the structure’s absolute safety. This investigation conducted wind tunnel tests for the construction and completion stages to reveal the vortex-induced vibration (VIV) phenomenon of a double-deck suspension bridge. The results showed that no VIV occurred during the construction stage. However, the inclusion of railings significantly deteriorated the aerodynamic performance of the suspension bridge, leading to significant VIV at +3° and +5° wind angles of attack. Additionally, reducing the railing ventilation rate can significantly suppress the VIV amplitude. A new analysis method based on computational fluid dynamics (CFD) simulation is proposed to investigate the VIV mechanism of the double-deck truss girder. Twenty-nine measurement points were used to explore the vortex that causes VIV. The numerical simulations found that the area above and aft of the upper deck dominated the vertical VIV, while the aft of the lower deck dominated the torsional VIV. Furthermore, the intensity of the vortex in these areas was significantly lower during the construction stage. Moreover, reducing the railing ventilation rate significantly suppresses the torsional VIV by reducing the intensity of the vortex in the region behind the lower deck.

Vortex-induced vibration performance and mechanism of long-span railway bridge streamlined box girder

To investigate the vortex-induced vibration (VIV) characteristics of a narrow-streamlined railway box girder and optimize its VIV performance, a long-span railway cable-stayed bridge was analyzed. Based on sectional model wind tunnel tests, the influence of the wind attack angle and the damping ratio on the VIV performance of the girder was investigated. The main inducing factors of the VIV of the narrow railway box girder were explored and a series of corresponding optimization schemes was put forward. The results show that there is no VIV when the wind attack angles are −5°, −3° and 0°, and the damping ratio is 0.2%. The non-dimensional maximum amplitudes 1000 y/ D of the girder at wind attack angles of +3° and +5° are 14.4 and 19.4, respectively. The maximum amplitudes decrease with the increase of the damping ratios. The railing base is the influence factor that induces the vertical VIV, because the separation vortices between the railing base and ballast wall, as well as behind the railings, cause the VIV of the railway steel box girder. Compared with that of the girder section with the ballastless track board, the non-dimensional maximum vertical VIV amplitude of the girder without the ballastless track board greatly increases from 19.4 to 63.5, which could effectively suppress the VIV of the main girder. Lastly, in the construction state, vertical VIV occurs for girder sections I and II, which have respective aspect ratios of 4.3 and 4.6, at wind attack angles of +3° and +5°. Girder section III, which has a 6.7 aspect ratio and is more streamlined, does not have a VIV. The greater the aspect ratio of the bridge girder, the better the VIV performance. The relevant results could serve as a guide for wind resistance design of railway streamlined box girders.

Machine learning-based deep data mining and prediction of vortex-induced vibration of circular cylinders

By means of numerical, experimental and field measurements, an unprecedented amount of data regarding vortex-induced vibration (VIV) of circular cylinders has become accessible recently. In this study, machine learning (ML) models are developed to predict the transverse VIV amplitude Y* and amplitude-velocity relations. First of all, an ML database is established by aggregating reliable, published data. Then, three ML techniques are developed, including support vector regression with particle swarm optimization (PSO + SVR), extreme learning machine (ELM), and improved ELM combined with preprocessed least squares QR decomposition (PLSQR + ELM). Three crucial parameters, mass damping ratio α, Reynolds number (Re) and mass ratio m*, are extracted by the partial least square (PLS) method to characterize VIV. The results show that the prediction accuracy of all algorithms is acceptable in the absence of noise, with the ELM-type being the highest. When noise is taken into account, PLSQR + ELM is the most efficient and robust. A new linear relation between the VIV amplitude Y* and log10(α/Re) is proposed, which is demonstrated to be better than published ones.

Prediction of Vortex-Induced Vibration Response of Open Bridge Girder Based on Machine Learning Method

The [Formula: see text]-shaped open section girder is a very common section, which has been widely used in the construction of modern bridges. However, compared with a streamlined box girder, it is easy to cause vortex-induced vibration (VIV) in bridges due to its bluff section shape and poor aerodynamic stability. In this paper, a typical open section with a height–width ratio of 10:1 is taken as the research object. Through wind tunnel tests and numerical simulation technology, the time-history data of VIV of the [Formula: see text]-shaped section are obtained. By selecting three different neural network models to establish the relationship between external parameters (wind attack angle, wind speed, turbulence) and structural response parameters (the onset wind speed of VIV, the length of the lock-in interval). After comparing different machine learning methods, the most suitable machine learning model is selected to predict the VIV response characteristics of the main girder. The research results show that the typical open section has a serious VIV phenomenon. The BP neural network model has the best performance in predicting the VIV performance of the open section in terms of calculation speed, prediction accuracy and solving nonlinear adaptability. At the same time, it is found that different characteristic parameters of the incoming wind field have different influences on the prediction results of the VIV response. Among them, the wind attack angle is the key parameter that affects the onset wind speed of VIV, but the turbulence intensity has a greater impact on the maximum amplitude of VIV. At the same time, the optimized BP model can predict the characteristic parameters of VIV response under unknown wind fields. This paper provides a new idea to study the effect of different incoming flow parameters on the performance of section VIV and further improves people’s understanding of VIV system.

RBF-PSO-IS: An innovative metamodeling for reliability analysis of bridge's vortex-induced vibration

The complexity of vortex-induced vibration (VIV) instability analysis originates from the variability of the wind environment, the randomness of the analytical model, the ambiguity of the failure criterion, and the high-dimensional nonlinearity and non-explicitness nature of the instability function. This paper addresses the low sampling efficiency and challenges in approximating failure probability in prior research on reliability. By integrating an adaptive sampling strategy with particle swarm optimization (PSO), an initial VIV reliability metamodel is established, which is subsequently resampled to create a more refined metamodel. A combination of multiple reliability algorithms is then employed to calculate the maximum amplitude of VIV and the failure probability of the VIV interval. The validity and accuracy of the proposed method are demonstrated through two representative numerical examples. The results indicate that the proposed radial basis function (RBF)-PSO-importance sampling (IS) analysis method and its adaptive random sampling strategy can significantly reduce the computational cost associated with extensive finite element model operations and the complexity arising from the high-dimensional nonlinearity and non-significance of the limit state function (LSF). This method enables researchers to achieve more accurate and time-saving solutions for VIV in steel–concrete composite bridges.