Structural Dynamic Response Analysis Research Articles

An Arbitrary Polygonal Stress Hybrid Element for Structural Dynamic Response Analysis

An Arbitrary Polygonal Stress Hybrid Element for Structural Dynamic Response Analysis

Comparative Analysis of Dynamic Response of Damaged Wharf Frame Structure under the Combined Action of Ship Collision Load and Other Static Loads

In the long-term service, the wharf structure can be damaged by ship impact, wave load, and even earthquake, which will affect the safe production and smooth operation of the port. Based on the theory of structural dynamic response analysis and wavelet packet analysis principle, this paper established the damage identification index of the wharf frame structure. Combining with the finite element method and the dynamic response theory of the wharf frame structure, it set up a finite element analysis model of the dynamic response of the wharf frame structure under the action of multiple loads, with the impact load of the ship as the dynamic load under the non-damaged state and the different damaged states. In addition, the characteristic response point location was drawn up. Furthermore, the transient dynamic analysis and damage index analysis of the frame structure in the non-damaged and damaged state were conducted respectively. In addition, the model test and numerical simulation results were combined to compare and analyze the identification of damage indicators, so as to verify the identification effect of the established damage identification indicators on the structural damage, which lays a foundation for the next step of structural damage identification.

A combined finite element and deep learning network for structural dynamic response estimation on concrete gravity dam subjected to blast loads

Social infrastructures such as dams are likely to be exposed to high risk of terrorist and military attacks, leading to increasing attentions on their vulnerability and catastrophic consequences under such events. This paper tries to develop advanced deep learning approaches for structural dynamic response prediction and dam health diagnosis. At first, the improved long short-term memory (LSTM) networks are proposed for data-driven structural dynamic response analysis with the data generated by a single degree of freedom (SDOF) and the finite numerical simulation, due to the unavailability of abundant practical structural response data of concrete gravity dam under blast events. Three kinds of LSTM-based models are discussed with the various cases of noise-contaminated signals, and the results prove that LSTM-based models have the potential for quick structural response estimation under blast loads. Furthermore, the damage indicators (i.e., peak vibration velocity and domain frequency) are extracted from the predicted velocity histories, and their relationship with the dam damage status from the numerical simulation is established. This study provides a deep-learning based structural health monitoring (SHM) framework for quick assessment of dam experienced underwater explosions through blast-induced monitoring data.

Structural Topology and Dynamic Response Analysis of an Electric Torque Vectoring Drive-Axle for Electric Vehicles

Structural Topology and Dynamic Response Analysis of an Electric Torque Vectoring Drive-Axle for Electric Vehicles

Calibration of Adjustment Coefficient of the Viscous Boundary in Particle Discrete Element Method Based on Water Cycle Algorithm

The viscous boundary has a direct influence on the accuracy of structural dynamic response analysis, and the absorbing effect of the viscous boundary is controlled by the adjustment coefficient. Therefore, a calibration model of the viscous boundary’s adjustment coefficient based on the water cycle algorithm is established for the particle discrete element to improve the accuracy of dynamic response analysis. First, the traditional viscous boundary theory is utilized to realize the viscous boundary’s application method in the particle discrete element via programming. This avoids the reflection and superposition of seismic waves at the boundary and makes the structural dynamic response with the particle discrete element more real and accurate. Second, for the complex and time-consuming adjustment coefficients determination, a calibration model based on the water cycle algorithm and Latin hypercube sampling is established for the adjustment coefficients in the particle discrete element method. Finally, this calibration model is employed for the seismic response analysis of a rockfill slope, the maximum velocity of rock in this rockfill slope being about 1.30 times that of a seismic wave. Comparing the rockfill slope response with fixed and viscous boundaries, the calibration’s accuracy and the viscous boundary’s feasibility are demonstrated, further expanding the research and application of the particle discrete element method in dynamic response analysis.

Parameter identification and dynamic response analysis of a modified Prandtl–Ishlinskii asymmetric hysteresis model via least-mean square algorithm and particle swarm optimization

Hysteresis is a nonlinear phenomenon observed in the dynamic response behavior of numerous structural systems under high intensity cyclic or random loading, as well as in numerous mechanical and electromagnetic systems. For several decades, hysteretic response analysis of structural systems has been widely studied and numerous hysteresis models have been proposed and utilized in order to reproduce and better understand the complex hysteretically degrading behavior of structural systems. An important area of research in this regard has been the parameter identification of hysteretic systems. In this paper, we propose a modified Prandtl–Ishlinskii model to simulate the asymmetric hysteresis, which is the complex behavior in structural systems. In addition, a new approach based on particle swarm optimization and least-mean square algorithm is utilized for parameter identification of this hysteresis model. Finally, the model is applied in structural dynamic response analysis of a base isolated structural model under seismic load.

Structural dynamic response of a locomotive hydraulic damper with welding imperfections

Railway vehicle hydraulic dampers are usually subject to premature structural failures, so it is meaningful to investigate the dynamic response of its welded main structure. FEA modelling of the welded rod-and-attachment assembly with imperfections of a Chinese electric locomotive axle-box hydraulic damper is performed, and load spectra of the axle-box hydraulic damper both under nominal and actual in-service conditions are obtained. Structural dynamics response analysis of the welded rod-and-attachment assembly of the damper is then conducted by using the FEA model and load spectra, and demonstrates that all of the maximum dynamic stresses have increased by 40% or so when using the actual in-service load spectra regardless of the weld joint condition, if the weld joint is with imperfection of misalignment of rod and attachment, the maximum dynamic stress has increased by 41.46%. Therefore, railway hydraulic dampers are usually subject to actual in-service load spectra instead of the nominal load spectra used in the design process, if the damper also has got welding imperfections, the damper would be readily subject to premature failures, this is why many current railway vehicle hydraulic dampers are still subject to premature failures despite with ‘perfect’ designs. The FEA model, the structural dynamic response analysis approach and results obtained in this work would be instructive in improving damper structure design, welding quality control and inspection.

Structural dynamic response analysis due to the slit flow between the tailplane and the elevator

Any aircraft in flight is subjected to dynamic loads. Following vibration-related accidents, a flow field and vibration analysis can be carried out to analyze the data and study the cause of the accident. When slit airflow enters the cavity between the tailplane structure and the elevator, a mixed vortex is formed. If the vortex-induced vibrational frequency of around 50 Hz happens to be close to the natural frequency of the structure at 46 Hz, it is likely to induce structural vibration (resonance). The resonance can cause excessive fatigue damage which can ultimately lead to structural failure and the loss of the component or the aircraft. Damping methods can be employed to control vibration within the structure by reducing the amplitude of that vibrational motion by 83%. This article details a recreation of one example of structural vibration within an airborne aircraft.

Nonstationary wind speed data reconstruction based on secondary correction of statistical characteristics

Data reconstruction is usually used for lost data recovery and data supplement in structural health monitoring (SHM) system. In this paper, a data reconstruction algorithm is proposed for the entire time series data missing at dispersed and consecutive multiple observation points. Kriging-based sequence interpolation (KSI) is adopted for primary data reconstruction and probability density function (PDF) reconstruction. In terms of dispersed data missing, the reconstructed PDF is of great accuracy, which is used to calculate the exact standard deviation to correct the primary reconstructed data and obtain satisfactory performance. Regarding the consecutive data missing, the first correction is insufficient due to the missing of too much information. In addition, it is found to exist a fuzzy mapping relation between the exact standard deviation and extreme values of wind speed series. Thus, the quantile regression combined with deep neural network is proposed for probability reconstruction of the extreme values. The point estimations are adopted to the secondary correction for the reconstructed data with first correction. The effectiveness and validity of the secondary correction strategy have been testified by structural dynamic response analysis. The extreme value of the displacement response under the reconstructed data with the secondary correction is closer to that under the actual wind data, compared with the reconstructed data with first correction.

Time history analysis method for the combined action of extreme fluctuating wind and wave on the maximum double cantilever structure of rigid frame bridge considering the influence of flow velocity

Taking the maximum double cantilever structure of rigid frame bridge in construction period as the research object, the structural dynamic response analysis under the combined action of extreme wind and wave is carried out, considering the influence of flow velocity. An analysis method of short-term pulsation effect of a structure is proposed considering the influence of various adverse factors under extreme wind and wave conditions, which provides a reference for structural safety assessment under extreme conditions; The dynamic response results of the maximum double cantilever structure of rigid frame bridge show that the wave-flow effect under extreme wind and wave conditions will increase the structural response during the construction period, resulting in adverse effects.

Modal Parameter Identification Based on Hilbert Vibration Decomposition in Vibration Stability of Bridge Structures

Modal parameters are important parameters for the dynamic response analysis of structures. An output‐only modal parameter identification technique based on Hilbert Vibration Decomposition (HVD) is developed herein for structural modal parameter identification to (1) obtain the Free Decay Response (FDR) of a structure through free vibration or ambient vibration tests, (2) decompose the FDR into modal responses using HVD, and (3) calculate the instantaneous frequencies and instantaneous damping ratios of the modal responses to obtain the modal frequencies and modal damping ratios. A series of numerical examples are examined to demonstrate the efficiency and highlight the superiorities of the proposed method relative to the empirical model decomposition‐based (EMD‐based) method. The robustness of the proposed method to noises is also investigated and proved to be positive effect. The proposed method is proved to be efficient in modal parameter identification for both linear and nonlinear systems, with better frequency resolution, and it can be applied to systems with closely spaced modes and low‐energy mode.

Kriging based sequence interpolation and probability distribution correction for gaussian wind field data reconstruction

Data reconstruction is an important research topic for missing data recovery and data supplement. Spatial interpolation is often used for data reconstruction. The interpolation for time series is usually conducted at each time point by common methods, which is sometimes inefficient. Additionally, statistical characteristics recovering may not be taken into account together during interpolation, which affects the utilization of data in structural design and safety assessment. In this paper, supposing that the data of a potential observation point are completely missing (no historical observation information at all), Kriging based Sequence Interpolation (KSI) combined with probability distribution correction is proposed for data reconstruction. KSI is proposed for two purposes. First, the primary interpolation results can be obtained by KSI, namely global interpolation once. Second, the Probability Density Function (PDF) of missing points can be reconstructed by KSI and subsequently provide a reference to correct the primary interpolation results. The proposed method is verified by both the simulated and field monitoring data, and the results show that the calculation efficiency is greatly improved compared with common methods. The fusion of data reconstruction and PDF reconstruction is novel and the effectiveness is verified via the structural dynamic response analysis. The RMS of structural displacement responses induced by the reconstructed wind load is almost coincide with that by the actual wind load.

Experimental Study on Dynamic Properties of UHMWPE and PVA Fibers Concrete

The purpose of this paper is to examine the dynamic three-point bending performance of UHMWPE and PVA fiber concrete specimens by means of density variation (0, 0.6, 1.2, 1.8, 2.4 kg/m3). Additionally, the difference in performance between UHMWPE and PVA fiber concretes, as well as the impact characteristics and the damage evolution law exhibited by these fiber concretes under repeated dynamic loading were studied and discussed. A Split Hopkinson pressure bar (SHPB) apparatus was used to determine the concrete behavior at different strain rates; the accuracy of which was achieved by conducting a structural transient dynamic response analysis. The dynamic failure strength and strain rate of the specimen were derived to investigate the rate effect with different quantities of UHMWPE and PVA fiber concretes. The experimental results were then compared with those predicted from available equations, verifying the validity of the results obtained. A theoretical model for analyzing the transient elastic response of the specimen was then proposed. This paper concludes by proposing an analytical equation for predicting the dynamic compression and tensile properties of these new-type fibers.

Discrete analytical mode decomposition with automatic bisecting frequency selection for structural dynamic response analysis and modal identification

Analytical mode decomposition (AMD) is one of dynamic response decomposition methods. However, the discretization of the dynamic responses and the selection of the bisecting frequency may cause the failure of the decomposition. In this study, the discrete analytical mode decomposition (DAMD) is investigated. In addition, an automatic bisecting frequency selection algorithm based on the auto-regressive power spectrum is proposed to effectively extract modal responses from the measured dynamic response. The efficiency of the proposed method is verified by a simulated dynamic signal with amplitude decays. Moreover, a 36-story frame structure with closely spaced modes subjected to a Gaussian white noise is simulated as a numerical example, and the dynamic responses of the frame structure are obtained based on the numerical simulation. The individual modal responses of the frame structure considering noise effect are effectively extracted by using the proposed method. Finally, the dynamic responses of a steel-concrete composite girder bridge are measured in the field under operational conditions. It is demonstrated that the measured dynamic responses are effectively decomposed into the modal responses. Based on the extracted modal responses, the modal parameters including natural frequencies, damping ratios and modal shapes of the 36-story frame structure and the tested bridge are further successfully identified accordingly.

Dynamic response analysis of structure with hybrid random and interval uncertainties

With the increasing complexity of uncertain parameters, the single uncertainty modeling is challenged for structures involving multiple types of uncertainties. However, in the contrast to research on static problems with hybrid uncertainties, dynamic mixed uncertainty problems have not been well addressed. A novel dynamic analysis of structure with hybrid uncertainties is developed for the expressions for the lower and upper bounds of the mean value and standard deviation of the dynamic response. Within this approach, interval variables are adopted to quantify the non-probabilistic uncertainty associated with objective limited information. Some other parameters are considered as random variables. Based on series expansion of random and interval quantities with respect to uncertain parameters, the proposed method evaluates the lower and upper bounds of the first- and second-order moments of the structure response through solving deterministic equations. This method is also capable to solve pure interval problems. Finally, numerical examples are analyzed to illustrate the feasibility and effectiveness of the proposed method. The influence on the structure response caused by the individual system parameters is also investigated.

Structural dynamic response analysis using deviations from idealized edge profiles in high-speed video

In our study, a deviation extraction method is introduced to obtain subtle deviation signals from structural idealized edge profiles. The deviations are employed to reconstruct an analysis matrix that consists of global translations along selected edge profiles, and then a singular value decomposition-based approach is proposed to extract valuable variations from the calculated analysis matrix. To avoid noises from textured edge profiles, a colorization optimization approach is applied to remove variations because of the textures and turn real image stripes into ones that satisfy the constant edge profile assumption more closely in the deviation extraction process. Two practical experiments are conducted to demonstrate the effectiveness and potential applications of our proposed method. The dynamic properties of a lightweight beam and a sound barrier are analyzed successfully by using high-speed videos.

Integrated Blast Resistance Model of Nuclear Power Plant Auxiliary Facilities

Standards, guidelines, manuals, and researches refer mainly to the required protection of a nuclear power plant (NPP) containment structure (where the reactor's vessel is located) against different internal and external extreme events. However, there is no consideration regarding the man-made extreme event of external explosion resulting from air bomb or cruise missile. A novel integrated blast resistance model (IBRM) of NPP's reinforced concrete (RC) auxiliary facilities due to an external above ground explosion based on two components is suggested. The first is structural dynamic response analysis to the positive phase of an external explosion based on the single degree-of-freedom (SDOF) method combined with spalling and breaching empirical correlations. The second is in-structure shock analysis, resulting from direct-induced ground shock and air-induced ground shock. As a case study, the resistance of Westinghouse commercial NPP AP1000 control room, including a representative equipment, to an external above ground blast loading of Scud B-100 missile at various standoff distances ranging from 250 m (far range) till contact, was analyzed. The structure's damage level is based on its front wall supports' angle of rotation and the ductility ratio (dynamic versus elastic midspan displacement ratio). Due to the lack of specific structural damage demands and equipment's dynamic capacities, common protective structures standards and manuals are used while requiring that no spalling or breaching shall occur in the control room while it remains in the elastic regime. The engineering systems and equipments' spectral motions should be less than their capacity. The integrated blast resistance model (IBRM) of the structure and its equipment may be used in wider researches concerning other NPP's auxiliary facilities and systems based upon their specifications.

Wave scattering method for dynamic response analysis of structures with stochastic parameters

ABSTRACTThe wave scattering method is presented to analyze dynamic response of frameworks with stochastic parameters. First, with the uncertain physical, geometric, and loading properties in consideration, the stochastic waveguide equations containing the axial, torsional and flexural wave modes are established. Second, the stochastic wave scattering equation and wave translation matrix are derived to obtain the wave modes. Third, the methodology to extract the generalized displacements and forces from stochastic wave modes is proposed. Finally, a cantilever beam, a planar framework, and a space framework have been presented as numerical examples to illustrate the efficiency of the proposed method. It is found that the results obtained by the proposed method with higher computational efficiency show an excellent agreement with those by Monte Carlo simulation method. Furthermore, the influences of stochastic parameters on dynamic response are revealed.

Dynamic response analysis of structure under time-variant interval process model

Due to the aggressiveness of the environmental factor, the variation of the dynamic load, the degeneration of the material property and the wear of the machine surface, parameters related with the structure are distinctly time-variant. Typical model for time-variant uncertainties is the random process model which is constructed on the basis of a large number of samples. In this work, we propose a time-variant interval process model which can be effectively used to deal with time-variant uncertainties with limit information. And then two methods are presented for the dynamic response analysis of the structure under the time-variant interval process model. The first one is the direct Monte Carlo method (DMCM) whose computational burden is relative high. The second one is the Monte Carlo method based on the Chebyshev polynomial expansion (MCM-CPE) whose computational efficiency is high. In MCM-CPE, the dynamic response of the structure is approximated by the Chebyshev polynomials which can be efficiently calculated, and then the variational range of the dynamic response is estimated according to the samples yielded by the Monte Carlo method. To solve the dependency phenomenon of the interval operation, the affine arithmetic is integrated into the Chebyshev polynomial expansion. The computational effectiveness and efficiency of MCM-CPE is verified by two numerical examples, including a spring-mass-damper system and a shell structure.

PDEM-Based Perspective to Probabilistic Seismic Response Analysis and Design of Earthquake-Resistant Engineering Structures

AbstractA perspective based on the probability density evolution method (PDEM) to the probabilistic seismic response analysis and design of earthquake-resistant engineering structures is provided in this paper. The development of characterization of randomness in seismic ground motions and nonlinear seismic dynamic response analysis of engineering structures are first reviewed and found to be almost independent, which hinders rapid adoption of refined methods for seismic design. The approaches for stochastic dynamics, which is expected to bridge the above gap, in earthquake engineering are revisited, which results in the statement that more physically based methodology is in urgent need for nonlinear stochastic dynamic response analysis of structures. This is the role that the PDEM will play, and thus the theoretical basis and some new advances of PDEM, including the ensemble evolution form of the generalized density evolution equation, ensemble evolution–based dimension reduction of Fokker-Planck-Kolmogo...