Shock and Vibration

https://www.hindawi.com/journals/sv/

List of Papers (Total 3,479)

Comparison of Presplit and Smooth Blasting Methods for Excavation of Rock Wells

To understand differences of smooth and presplit blasting for the excavation of rock wells, two field experiments using these two techniques are implemented at the same test site, respectively. The ground vibrations induced by them have been monitored with the different distances through the corresponding devices. The vibration results illustrate that at the same monitoring...

Study on Roof-Coal Caving Characteristics with Complicated Structure by Fully Mechanized Caving Mining

With mining technology and mechanization degree being improving, fully mechanized caving mining technology (FCM) has become a main method for thick coal seam extraction in China. However, roof-coal caving characteristics in turn restrict its recovery efficiency, especially for the coal seam with complicated structure (CCS), that is, the coal seam comprises hard or soft coal and...

An Improved Principle of Rapid Oscillation Suppression of a Pendulum by a Controllable Moving Mass: Theory and Simulation

An improved principle is proposed in this paper to achieve a more efficient amplitude suppression of an oscillating pendulum by a controllable moving mass. By establishing the governing equation of the pendulum with a moving mass, several suppression rules are presented to stipulate the motion parameters of the moving mass. The damping ratio is introduced to quantify the...

Effect of Surface Coatings on Cylinders Exposed to Underwater Shock

The response of a coated cylinder (metallic cylinder coated with a rubber material) subjected to an underwater explosion is analyzed numerically. The dynamic response of the coated cylinder appears to be adversely affected when impacted by an underwater shock wave under certain conditions of geometry and material properties of the coating. When adversely affected, significant...

Continuous Sliding Mode Control of Flow-Induced Vibrations

Vortex-induced vibrations of flexible circular cylinders and galloping oscillations of square prisms are controlled using a robust continuous sliding mode (CSM) controller. The ability of the CSM controller in rejecting the flow-induced disturbances and accommodating parameter uncertainties is numerically demonstrated. In the present study, emphasis is placed on the development...

Vent Control as a Means of Enhancing Airbag Performance

Typical automotive airbag systems have a fixed area vent for exiting gasses. The US Army Cockpit Airbag System (CABS) is unvented to prolong the period during which the system can provide occupant protection during extended helicopter crash scenarios. In each application, system performance may be enhanced by providing a controlled vent area. This paper describes work conducted...

An EEMD-Based Denoising Method for Seismic Signal of High Arch Dam Combining Wavelet with Singular Spectrum Analysis

Due to complicated noise interference, seismic signals of high arch dam are of nonstationarity and a low signal-to-noise ratio (SNR) during acquisition process. The traditional denoising method may have filtered effective seismic signals of high arch dams. A self-adaptive denoising method based on ensemble empirical mode decomposition (EEMD) combining wavelet threshold with...

Study on the Rolling-Type Microvibration Isolation Mechanisms Based on Completely Elastic Contact

The previous models of rolling-type mechanisms were built based on rigid contact and pure rolling motion, but when applied to ground microvibration isolation, a large error in the natural frequency was sometimes observed in the experiments. A new model of a common mechanism based on completely elastic contact is developed, and the expression of the natural frequency is provided...

A Simplified Finite Element Approach for Modeling of Multilayer Plates

The multilayer plate has a great potential for automotive and aerospace applications. However, the complexity in structure and calculation of the response impede the practical applications of multilayer plates. To solve this problem, this work proposes a new plate finite element and a simplified finite element (FE) model for multilayer plates. The proposed new plate finite...

Chaotic Threshold for a Class of Power System Model

This paper deals with the bifurcation and chaotic dynamic characteristic of a single-machine infinite-bus (SMIB) power system under two kinds of harmonic excitation disturbance, which are induced by the external periodic load and the outer mechanical disturbance. By applying Melnikov’s method, the threshold value for the occurrence of chaotic motion is provided. In addition, the...

Framework for Dynamic-Stiffness-Based Free Vibration Analysis of Plate-Like Structures

A framework for free vibration analysis of plate-like structures is presented in the paper. Based on the previously formulated dynamic stiffness elements, FREEVIB object-oriented software in Python environment has been created. Software design and structure as well as a wide range of possible structural problems that could be analyzed using the FREEVIB are presented. Through...

Formulation of a Linearized Model for Vehicle-Track Interactions

In this paper, a fundamental wheel-rail interaction (WRI) element accompanied by its coupling matrices with other vehicle-track components have been derived taking into consideration the aspect of linearization. The key to the presented formulation is the use of the geometrical relationships of relative motions between degrees of freedom (DOFs) and energy principle. To the WRI...

Data Inspecting and Denoising Method for Data-Driven Stochastic Subspace Identification

Data-driven stochastic subspace identification (DATA-SSI) is frequently applied to bridge modal parameter identification because of its high stability and accuracy. However, the existence of abnormal data and noise components may make the identification result of DATA-SSI unreliable. In order to achieve a reliable identification result of the bridge modal parameter, a data...

Experimental Study of a Low-Specific Speed Francis Model Runner during Resonance

An analysis of the pressure in a runner channel of a low-specific speed Francis model runner during resonance is presented, which includes experiments and the development of a pressure model to estimate both the convective and acoustic pressure field from the measurements. The pressure was measured with four pressure sensors mounted in the runner hub along one runner channel. The...

Scale Effect on the Anisotropy of Acoustic Emission in Coal

Acoustic emission (AE) in coal is anisotropic. In this paper, we investigate the microstructure-related scale effect on the anisotropic AE feature in coal at unconfined loading process. A series of coal specimens were processed with diameters of 25 mm, 38 mm, 50 mm, and 75 mm (height to diameter ratio of 2) and anisotropic angles of 0°, 15°, 30°, 45°, 60°, and 90°. The cumulative...

Source Contribution Analysis for Exterior Noise of a High-Speed Train: Experiments and Simulations

This paper presents a detailed investigation into the contributions of different sound sources to the exterior noise of a high-speed train both experimentally and by simulations. The in situ exterior noise measurements of the high-speed train, including pass-by noise and noise source identification, are carried out on a viaduct. Pass-by noise characteristics, noise source...

Source Contribution Analysis for Exterior Noise of a High-Speed Train: Experiments and Simulations

This paper presents a detailed investigation into the contributions of different sound sources to the exterior noise of a high-speed train both experimentally and by simulations. The in situ exterior noise measurements of the high-speed train, including pass-by noise and noise source identification, are carried out on a viaduct. Pass-by noise characteristics, noise source...

Temperature Energy Influence Compensation for MEMS Vibration Gyroscope Based on RBF NN-GA-KF Method

This paper proposed three methods to compensate the temperature energy influence drift of the MEMS vibration gyroscope, including radial basis function neural network (RBF NN), RBF NN based on genetic algorithm (GA), and RBF NN based on GA with Kalman filter (KF). Three-axis MEMS vibration gyroscope (Gyro X, Gyro Y, and Gyro Z) output data are compensated and analyzed in this...

Design and Efficiency Research of a New Composite Vibrating Screen

A new composite vibrating mode is presented in this paper. Modeling and dynamic analysis are studied according to two-degree-of-freedom systems theory. The effects of vibration parameters, including swing angle, swing frequency, vibrating direction angle, and translation frequency, on the screening efficiency were researched by means of experiment research over a new laboratory...

Dynamic Finite Element Analysis of a New Type Flexible Rock Shed under the Impact of Rock Block and Improving the Design

A 1:1 flexible rock shed made of flexible nets and steel-vaulted structure is manufactured and tested for functional evaluation with impact experiment previously. To further discuss the performance of this structure under the impact of rockfalls and to improve the design, numerical simulation for this structure is carried out in this paper. Firstly, the simplified numerical...

Application of Control Rods for Passively Suppressing Cross-Flow VIV of an Inclined Flexible Cylinder

Laboratory experiments were conducted to investigate the cross-flow (CF) vortex-induced vibration (VIV) suppression effectiveness of an inclined flexible cylinder by using control rods. 4 control rods with a diameter of 0.25D (where D is the diameter of the main cylinder) and outer wall distance between the control rod and the main cylinder of 0.50D were attached to the main...

Rockburst Characteristics and Mechanisms during Steeply Inclined Thin Veins Mining: A Case Study in Zhazixi Antimony Mine, China

With the increase of mining depth, rockbursts have become important safety problems in Zhazixi Antimony Mine, where overlying strata exceed 560 m. Due to the small spacing between the steeply inclined veins, mining activities have great influences on rockbursts of adjacent veins. In order to study rockburst characteristics and mechanisms in Zhazixi Antimony Mine, in situ...

Underwater Acoustic Communication by a Single-Vector Sensor: Performance Comparison Using Three Different Algorithms

In November, 2014, the underwater acoustic (UWA) communication experiment by a single-vector sensor was conducted in shallow water environment. In this paper, three different algorithms are used to process the experimental data and their performance are compared in terms of equalized output signal to noise ratio (OSNR) and bit error rate (BER). The three algorithms are P-DFE, B...