Lateral vibration estimation of an elevator rope by sequential modal decomposition of elevator rope displacement observed near the traction sheave

This paper presents a numerical procedure for investigating the dynamic behaviour of a planar steel frame subjected to turbulent wind loads. The main objective is to emphasize the modal distribution of top lateral displacements induced by time varying wind forces. Time histories of pressure and forces were acquired for a time period of 600 s from a Computational Fluid Dynamic (CFD) analysis. Air flow over rectangular bluff bodies was modelled in a bounded CFD domain in order to simulate wind’s stochastic behaviour in the presence of roughness. Simulated pressure in the CFD analysis is transferred as time-varying load applied on a steel shear frame. The studied structure is mathematically modelled as a dynamic multi-degree-of-freedom (MDOF) system directly related to its constituent stiffness, mass and damping matrices. Forced vibrations induced by highly arbitrary wind forces are dealt with Duhamel’s Integral to emphasise the modal decomposition of the overall lateral displacements response. Wind load function defined as a time-history of discrete force values requires the use of Simpson’s 1/3 Rule for numerical integration.

Prediction of the displacement in a foundation pit based on neural network model fusion error and variational modal decomposition methods

When the total nitrogen content in water sources exceeds the standard, it can promote the rapid proliferation of algae and other plankton, leading to eutrophication of the water body and also causing damage to the ecological environment of the water source area. Therefore, making timely and accurate predictions of water quality at the source is of vital importance. Since water quality data exhibit non-stationary characteristics, predicting them is quite challenging. This study proposes a novel hybrid deep learning model based on modal decomposition, ERSCB (EMD-RBMO-SVMD-CNN-BiGRU), to enhance the accuracy of water quality forecasting. The model first employs Empirical Mode Decomposition (EMD) technology to decompose the original water quality data. Subsequently, it quantifies the complexity of the subsequences obtained from EMD using Sample Entropy (SE) and further decomposes the most complex subsequences using Sequential Variational Mode Decomposition (SVMD). To address the matter of selecting balanced parameters in SVMD, this study introduces the Red-Billed Blue Magpie Optimization (RBMO) algorithm to optimize the hyperparameters of SVMD. On this basis, a forecasting model is constructed by integrating Convolutional Neural Networks (CNN) and Bidirectional Gated Recurrent Unit (BiGRU) networks. The experimental results show that, compared to existing water quality prediction models, the ERSCB model has an improved prediction accuracy of 4.0% and 3.1% for the KaShi River and GongNaiSi River areas, respectively.

In the vibration analyses for the elevator systems, especially in high-rise buildings, the elevator rope is assumed as an elastic model. There are two types of vibrations in the rope. One is the longitudinal vibration, and the other is the lateral one. Accordingly it is desirable to consider longitudinal and lateral vibrations at the same time. However many conventional works have been carried out with the longitudinal and lateral vibrations separately. This paper proposes a wave transmission model for the behavior of the lateral vibration of rope coupled with the longitudinal vibration. We explain the process of constitution for the analytical model. Furthermore, the validity of proposed model will be shown through some experimental results.

To mitigate the susceptibility of absorption lines to noise interference during gas measurement using the off-axis integrated cavity output spectroscopy (OA-ICOS) technique, thereby enhancing measurement accuracy, this paper introduces a novel denoising method. This method synergistically integrates Grey Wolf Optimization (GWO) and Cuckoo Search (CS) with Singular Value Decomposition (SVD) and Sequential Variational Mode Decomposition (SVMD). Initially, the optimal solution for the quadratic penalty coefficient in SVMD is ascertained via iterative optimization using the CSGWO algorithm. Subsequently, a circulant matrix is established to extract the singular values of each modal component. A threshold is set to discriminate between noise and useful signals, and the singular values corresponding to noise are nullified. The useful signal components are then reconstructed, yielding the final processed signal. The proposed algorithm was applied to both simulated and experimental target signals and compared with common filtering algorithms such as WT, VMD-WTD, and S-G. In the experimental signal processing results, the signal-to-noise ratio (SNR) of the absorption spectrum signal improved from 21.4 to 39.95, and the correlation coefficient increased from 0.99715 to 0.99946. Results indicate that the proposed algorithm exhibits superior identification and noise suppression capabilities compared to other algorithms. After signal processing using the CSGWO-SVMD-SVD algorithm, the accuracy and stability of signal data detected based on off-axis integration cavity output spectroscopy technology have been greatly improved.

A day-ahead wind speed correction method: Enhancing wind speed forecasting accuracy using a strategy combining dynamic feature weighting with multi-source information and dynamic matching with improved similarity function

Elevator ropes for a high-rise building are excited forcibly by the sway of the building caused by wind forces and long-period ground motion. This paper describes about effective damping method of the elevator ropes lateral vibration. The behavior of the elevator ropes is influenced by interaction between deflection of the elevator rope and the movement of a compensation sheave. By using the interaction, it is possible to damp the elevator ropes. Specifically, the lateral vibration of the elevator ropes is damped by attaching a damper to a compensation sheave and resisting vertical vibration of this sheave. In this research, we verified the effect of this damping method by performing experiments and simulations.

In the vibration analyses for the elevator systems, especially in high-rise buildings, the elevator rope is assumed as an elastic model. There are caused two vibrations in the rope. One is the longitudinal vibration, and the other is the lateral one. Accordingly it is desirable to consider longitudinal and lateral vibrations at the same time. However many conventional works have been carried out with the longitudinal and lateral vibrations separately. This paper proposes a wave transmission model for the behavior of the lateral vibrating rope coupled with the longitudinal vibration. We explain the process of constitution for the analytical model. Furthermore, the validity of proposed model will be shown through some experimental data

IntroductionTo address the challenges of cumulative errors, insufficient modeling of complex spatiotemporal features, and limitations in computational efficiency and generalization ability in 4D trajectory prediction, this paper proposes a high-precision, robust prediction method.MethodsA hybrid model SVMD-DBO-RCBAM is constructed, integrating sequential variational modal decomposition (SVMD), the dung beetle optimization algorithm (DBO), and the ResNet-CBAM network. Innovations include frequency-domain feature decoupling, dynamic parameter optimization, and enhanced spatio-temporal feature focusing.ResultsExperiments show that the model achieves a low longitude MAE of 0.0377 in single-step prediction, a 38.5% reduction compared to the baseline model; in multi-step prediction, the longitude R2 reaches 0.9844, with a 72.9% reduction in cumulative error rate and an IQR of prediction errors less than 10% of traditional models, demonstrating high accuracy and stability.DiscussionExperiments show that the model achieves a low longitude MAE of 0.0377 in single-step prediction, a 38.5% reduction compared to the baseline model; in multi-step prediction, the longitude R2 reaches 0.9844, with a 72.9% reduction in cumulative error rate and an IQR of prediction errors less than 10% of traditional models, demonstrating high accuracy and stability.

Elevator rope for high-rise building vibrates largely due to the resonance of the building and the elevator rope by the displacement of the building induced by strong winds and earthquakes. As building heights increase, elevator rope becomes longer. These factors cause problems of collisions and entanglement to the hoistway equipment of the elevator. Therefore, suppression of elevator rope vibration is desired. In previous paper, when elevator cage is stationary, a practical method for reducing the rope vibration by using vibration suppressors is proposed for relaxing the restricted elevator operation. The advantage of using the vibration suppressors for reducing the rope lateral vibration is demonstrated through numerical calculation. Further, an exact solution to the free vibration of the rope with vibration suppressors located at 1/N from both ends of the rope has been presented in the case where N is an odd number. However, in the case where N is an even number, no exact solution of the free vibration has yet been obtained. In this paper, an exact solution to the free vibration of this case (N is an even number) is presented, when center position of the rope is pulled. The rope is modeled with string. Finite difference analyses of the rope vibration with vibration suppressor are also performed. The calculated results of the finite difference analyses are in good agreement with those of the exact solution.

An elevator rope for high-rise building is forcibly excited by the displacement of the building caused by earthquakes and wind forces. In high-rise building, the elevator rope may resonate with the natural frequency of the building; hence, effective solution to reduce the rope displacement is demanded. In this paper, it is confirmed to suppress of the transverse vibration of elevator rope using vertical vibration of counterweight. Rope lateral vibration is controlled by fluctuating rope tension using up-and-down motion of this counterweight. Finite difference analyses of rope vibration with counterweight are performed to verify of this method. Experiments involving forced vibration of a rope whose length is constant are performed. The optimal natural frequency of vertical vibration is about 2 times of the natural frequency of the rope.

The large displacement of the rope may cause damages to the equipment and the shaft due to the natural period of the high-rise buildings and the elevator rope are close. In this paper, an elevator rope lateral vibration analysis system has been developed. In the results of long-period ground motion, the maximal displacement of the rope is increase, main rope is easy to sway with a first mode when maximum displacement is center of rope, compensating rope is easy to sway with more than second mode when maximum displacement is bottom of rope.

When an elevator rope for a high-rise building is forcibly excited by the displacements of the building induced by wind forces and/or by long-period ground motion. In previous paper, when elevator cage is stationary, a new practical method for reducing the rope vibration by using vibration suppressors is proposed for relaxing the restricted elevator operation. The advantage of using the vibration suppressors for reducing the rope lateral vibration is demonstrated through numerical calculation. However, theoretical solution to the vibration of the rope with vibration suppressors has not yet been obtained. In this paper, a theoretical solution to the free vibration of the rope with vibration suppressors is presented, in the case of that vibration suppressors are arranged at equal intervals. Finite difference analyses of the rope vibration with/without vibration suppressors are also performed. The effect of the number of vibration suppressors on the natural frequency and rope deflection are clarified. The calculated results of the finite difference analyses are in fairly good agreement with the calculated results of the theoretical solution.

Computational studies of heterogeneous reactions of SiH 2 on Si(111) surfaces

This paper is dealing with the lateral vibration of simply supported beam induced by one crossing pedestrian. Effects of pedestrian on the structural vibration was simplified by deterministic, stationary, periodic forces, which were placed at the most efficient spot on the structure. A new approach to modeling of excitation of lateral vibration was also introduced. This model is based on the "real" trajectory of pedestrian's centroid and it also reflects fact, that the pedestrian is changing his position in time. Numerical solution of this problem was done by Newmark integration method with using modal decomposition technique.