Shock and Vibration

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

List of Papers (Total 159)

Parameter and State Estimation of Shear Buildings Using Spline Interpolation and Linear Integral Filters

A parameter identification method and a high gain observer are proposed in order to identify the model and to recover the state of a seismically excited shear building using acceleration responses of the ground and instrumented floors levels, as well as the responses at noninstrumented floors, which are reconstructed by means of cubic spline shape functions. The identification...

Composites Bond Inspection Using Heterodyne Effect and SuRE Methods

With increasing utilization of the composite materials in commercial and military applications, the longevity of composite bonds has become a crucial concern of the aerospace industry. In spite of the previous studies in the literature for characterization of bonding condition in composite materials, implementation of more advanced structural health monitoring (SHM) techniques...

Fault Diagnosis Research on Impact System of Hydraulic Rock Drill Based on Internal Mechanism Testing Method

In the production and manufacturing process of hydraulic rock drill, there are small impact energy and low impact frequency, and a fault diagnosis method based on the internal mechanism testing and testing of the hydraulic rock drill is proposed. This method is used to test the change law of hydraulic oil in the rock drill, by retaining the test holes on the cylinder body and...

Hybrid Filtered-x Adaptive Vibration Control with Internal Feedback and Online Identification

Active control is an effective way to suppress low-frequency mechanical vibration. However, with applications to submarine equipment, there are still some shortcomings due to vibration coupling and multifrequency complex excitation. In this paper, a novel hybrid improved adaptive control strategy, feedback and online identification filtered-x LMS, namely, FOFxlms, is proposed...

A Nonparametric Method for Automatic Denoising of Microseismic Data

Noise suppression or signal-to-noise ratio (SNR) enhancement is often desired for better processing results from a microseismic dataset. In this paper, we proposed a nonparametric automatic denoising algorithm for microseismic data. The method consists of three major steps: (1) applying a two-step AIC algorithm to pick P-wave arrival; (2) subtracting the noise power spectrum from...

Fault Diagnosis for Reducer via Improved LMD and SVM-RFE-MRMR

The vibration signals are usually characterized by nonstationary, nonlinearity, and high frequency shocks, and the redundant features degrade the performance of fault diagnosis methods. To deal with the problem, a novel fault diagnosis approach for rotating machinery is presented by combining improved local mean decomposition (LMD) with support vector machine–recursive feature...

Feature Frequency Extraction Based on Principal Component Analysis and Its Application in Axis Orbit

Vibration-based diagnosis has been employed as a powerful tool in maintaining the operating efficiency and safety for large rotating machinery. However, the extraction of malfunction features is not accurate enough by using traditional vibration signal processing techniques, owing to their intrinsic shortcomings. In this paper, the relationship between effective eigenvalues and...

Experimental Study on the Stress Sensitivity and Influence Factors of Shale under Varying Stress

Shale reservoirs are characterized by extremely low permeability and high clay content. To further study the stress sensitivity of a shale reservoir, the Lower Cambrian shale in north Guizhou was utilized. Through laboratory testing, the relationships between the shale porosity and permeability and the effective stress were established, and the stress sensitivity of shale was...

A Dynamic Coefficient Matrix Method for the Free Vibration of Thin Rectangular Isotropic Plates

The free flexural vibration of thin rectangular plates is revisited. A new, quasi-exact solution to the governing differential equation is formed by following a unique method of decomposing the governing equation into two beam-like expressions. Using the proposed quasi-exact solution, a Dynamic Coefficient Matrix (DCM) method is formed and used to investigate the free lateral...

Bending Moment Characteristics of Hard Roof before First Breaking of Roof Beam Considering Coal Seam Hardening

The mechanical properties of a coal seam affect the distribution of support pressure. Considering the strain hardening effect of coal seam, the support pressure relationship of three zones—softened, hardened, and elastic—of a coal seam with regard to a hard roof is proposed, and methods to determine an approximate expression for the support pressure of hardened zone of coal seam...

A Copula-Based and Monte Carlo Sampling Approach for Structural Dynamics Model Updating with Interval Uncertainty

As the uncertainty is widely existent in the engineering structure, it is necessary to study the finite element (FE) modeling and updating in consideration of the uncertainty. A FE model updating approach in structural dynamics with interval uncertain parameters is proposed in this work. Firstly, the mathematical relationship between the updating parameters and the output...

Study on Influence of Diversified Parameters of Vehicle and Track on Wheel Hollow Wear

Wheel hollow wear of high-speed train is one of the main damage types for the wheel. By optimizing the vehicle and track parameters and matching the wheel-rail profile, the hollow wear of wheel can be reduced. In order to study the sensitivity of vehicle and track parameters to the wheel hollow wear, the sensitivity of suspension parameters and the track parameters of the...

Seismic Response of the Three-Span Bridge with Innovative Materials Including Fault-Rupture Effect

The seismic performance of the SR99 Bridge with conventional and advanced details in Seattle, Washington, was studied via a nonlinear, time history analysis of a multidegree of freedom model. The bridge consists of three spans supported on two single-column piers and will be the first built bridge in the world in which superelastic shape memory alloy (SMA) and engineered...

Analysis of Blast Wave Parameters Depending on Air Mesh Size

Results of numerical simulations of explosion events greatly depend on the mesh size. Since these simulations demand large amounts of processing time, it is necessary to identify an optimal mesh size that will speed up the calculation and give adequate results. To obtain optimal mesh sizes for further large-scale numerical simulations of blast wave interactions with overpasses...

Remaining Useful Life Prediction Method of Rolling Bearings Based on Pchip-EEMD-GM(1, 1) Model

A trend prediction method based on the Pchip-EEMD-GM(1,1) to predict the remaining useful life (RUL) of rolling bearings was proposed in this paper. Firstly, the dimension of the extracted features was reduced by the KPCA dimensionality reduction method, and the WPHM model parameters were estimated via the kernel principal components. Secondly, the hazard rate was calculated at...

Response Surface Method for Material Uncertainty Quantification of Infrastructures

Recently, probabilistic simulations became an inseparable part of risk analysis. Managers and stakeholders prefer to make their decision knowing the existing uncertainties in the system. Nonlinear dynamic analysis and design of infrastructures are affected by two main uncertainty sources, i.e., epistemic and aleatory. In the present paper, the epistemic uncertainty is addressed...

An Analytical Model for a Pneumatic Vibration Isolator with the Stiffness Effect of the Elastomeric Diaphragm

The elastomeric diaphragm is widely used in pneumatic vibration isolators, and the relevant model is often ignored due to its complexity. Considering that the ignored model of the elastomeric diaphragm in pneumatic vibration isolators plays an important role in the discrepancy between the predicted and practical behavior, this paper develops an analytical model for the...

Theoretical Calculation and Experimental Analysis on Initial Shock Pressure of Borehole Wall under Axial Decoupled Charge

This paper attempts to calculate the exact initial shock pressure of borehole wall induced by the blasting with axially decoupled charge. For this purpose, Starfield superposition was introduced considering the attenuation and superposition of blasting pressure, and the theoretical solution of initial borehole wall pressure was obtained for the upper and middle air-decked...

A Risk Assessment Method for Rockburst Based on Geodynamic Environment

Rockbursts are the sudden release of accumulated energy in surrounding rock of roadway and stope. Current studies on the rockburst mechanism are primarily focused on underground mining space and mining activities, whereas efforts have rarely been focused on regional geological dynamics. Mining activities in areas of energy accumulation under the influence of regional geological...

Experimental Study on Seismic Dynamic Characteristics of Shallow-Bias Tunnel with a Small Space

In order to obtain the seismic dynamic characteristics of a shallow-bias tunnel with a small space, a series of large-scale shaking table model tests were carried out. The key technology of the test is introduced in detail, for example, similar ratios of model, test equipment, testing model box, testing model, sensor arrangement, seismic waves, and testing system. The results...

Vibratory Power Flow Analysis of a Gear-Housing-Foundation Coupled System

The marine gearbox is usually installed on a vibration isolation system in order to reduce oscillation transmitted to the ship foundation. However, researches on vibration transmission in the gear-housing system and isolation system are currently independent. With the increasing requirement of lower vibration, a coupled model needs to be built to control the vibration propagation...

Reference Value Selection in a Perturbation Theory Applied to Nonuniform Beams

The Lindstedt-Poincaré method is applied to a nonuniform Euler-Bernoulli beam model for the free transverse vibrations of the system. The nonuniformities in the system include spatially varying and piecewise continuous bending stiffness and mass per unit length. The expression for the natural frequencies is obtained up to second-order and the expression for the mode shapes is...

Temperature Effects on Nonlinear Vibration Behaviors of Euler-Bernoulli Beams with Different Boundary Conditions

This paper is concerned with temperature effects on the modeling and vibration characteristics of Euler-Bernoulli beams with symmetric and nonsymmetric boundary conditions. It is assumed that in the considered model the temperature increases/decreases instantly, and the temperature variation is uniformly distributed along the length and the cross-section. By using the extended...

An Experimental Investigation on the Relationship between MS Frequency Response and Coal and Gas Outburst

Microseismic (MS) frequency response is an important part of high-efficiency data mining to achieve the aim of coal and gas outburst (CGOB) early warning. Based on the variation pattern of acoustic emission (AE) signal in the coal failure process, the experimental characteristics of MS activity and typical signals CGOB were obtained in this study. First, the AE behavior of coal...

Proposal of a Viscous Model for Nonviscously Damped Beams Based on Fractional Derivatives

Viscoelastic materials are widely used in structural dynamics for the control of the vibrations and energy dissipation. They are characterized by damping forces that depend on the history of the velocity response via hereditary functions involved in convolution integrals, leading to a frequency-dependent damping matrix. In this paper, one-dimensional beam structures with...