Shock and Vibration https://www.hindawi.com The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Numerical Study on the In-Plane and Out-of-Plane Resistance of Brick Masonry Infill Panels in Steel Frames Sun, 28 May 2017 07:49:39 +0000 http://www.hindawi.com/journals/sv/2017/8494657/ Masonry infill walls are one of the main forms of interior partitions and exterior walls in many parts of the world. Nevertheless, serious damage and loss of stability of many masonry infill walls had been reported during recent earthquakes. To improve their performance, the interaction between these infill walls and the bounding frames needs to be properly investigated. Such interaction can dramatically increase the stiffness of the frame in the in-plane direction. To avoid the negative aspects of inappropriate interactions between the frame and infill wall, some kind of isolation needs to be introduced. In this paper, three different configurations have been evaluated by using the general finite element software, ABAQUS. Nonlinear pushover and time history analyses have been conducted for each of the three configurations. Results showed that isolation of the infill from the frame has a significant effect on the in-plane response of infilled frames. Furthermore, adequate out-of-plane stability of the infill wall has been achieved. The results show that masonry infill walls that have full contact at the top of the wall but isolated from columns have shown acceptable performance. Vahid Bahreini, Tariq Mahdi, and MohammadMahdi Najafizadeh Copyright © 2017 Vahid Bahreini et al. All rights reserved. An Observer-Based Controller with a LMI-Based Filter against Wind-Induced Motion for High-Rise Buildings Thu, 25 May 2017 08:36:07 +0000 http://www.hindawi.com/journals/sv/2017/1427270/ Active mass damper (AMD) control system is proposed for high-rise buildings to resist a strong wind. However, negative influence of noise in sensors impedes the application of AMD systems in practice. To reduce the adverse influence of noise on AMD systems, a Kalman filter and a linear matrix inequality- (LMI-) based filter are designed. Firstly, a ten-year return period fluctuating wind load is simulated by mixed autoregressive-moving average (MARMA) method, and its reliability is tested by wind speed power spectrum and correlation analysis. Secondly, a designed state observer with different filters uses wind-induced acceleration responses of a high-rise building as the feedback signal that includes noise to calculate control force in this paper. Finally, these methods are applied to a numerical example of a high-rise building and an experiment of a single span four-storey steel frame. Both numerical and experimental results are presented to verify that both Kalman filter and LMI-based filter can effectively suppress noise, but only the latter can guarantee the stability of AMD parameters. Chao-Jun Chen, Zuo-Hua Li, Jun Teng, Wei-Hua Hu, and Ying Wang Copyright © 2017 Chao-Jun Chen et al. All rights reserved. Formation Mechanism and Reduction Technology of Mining-Induced Fissures in Shallow Thick Coal Seam Mining Thu, 25 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/1980817/ Surface mining-induced fissures formed in shallow coal seam mining have serious impact on safety mining and water resources protection. This paper proposes a novel approach to study the formation mechanism and dynamic development of surface mining-induced fissures in shallow coal seam mining. This approach combines field tests, theoretical analysis, and numerical simulations based on the geological condition of shallow coal seam mining in Chuancao Gedan Coal Mine. Two typical surface mining-induced fissures, step-type fissures and collapse-type fissures, are generated in shallow coal seam mining. The fissures with large vertical throw or horizontal opening severely impact water resource protection and surface ecological environment. Surface mining-induced fissures are generated periodically and changed dynamically with the advancing of working face. The vertical throw and horizontal opening of surface fissures are changed dynamically with the movement of loading key strata. The movement forms of loading key strata determine the morphological development of surface fissures. Downward sliding movement of broken rocks causes step-type fissures, while downward rotation movement leads to collapse-type fissures. The degree of the downward sliding and rotation of broken rocks determines the vertical throw and horizontal opening of surface fissures. This paper proposes mining technologies to reduce damaging ground fissures in shallow coal seam mining and analyzes their control effects. Jianwei Li and Changyou Liu Copyright © 2017 Jianwei Li and Changyou Liu. All rights reserved. Design Fuzzy Input-Based Adaptive Sliding Mode Control for Vessel Lift-Feedback Fin Stabilizers with Shock and Vibration of Waves Thu, 25 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/9095287/ An adaptive sliding mode controller based on fuzzy input design is presented, in order to reduce the roll motion of surface vessel fin stabilizers with shock and vibration of waves. The nonlinearities and uncertainties of the system including feedback errors and disturbance induced by waves are analyzed. And the lift-feedback system is proposed, which improves the shortage of conventional fin angle-feedback. Then the fuzzy input-based adaptive sliding mode control is designed for the system. In the controller design, the Lyapunov function is adopted to guarantee the system stability. Finally, experimental results demonstrate the superior performance of the controller designed using fuzzy input, when compared to the PID controller used in practical engineering. Lihua Liang, Mingxiao Sun, and Tiantian Luan Copyright © 2017 Lihua Liang et al. All rights reserved. Three-Dimensional Vibration Analysis of Rectangular Thick Plates on Pasternak Foundation with Arbitrary Boundary Conditions Mon, 22 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/3425298/ This paper presents the first known vibration characteristic of rectangular thick plates on Pasternak foundation with arbitrary boundary conditions on the basis of the three-dimensional elasticity theory. The arbitrary boundary conditions are obtained by laying out three types of linear springs on all edges. The modified Fourier series are chosen as the basis functions of the admissible function of the thick plates to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges. The exact solution is obtained based on the Rayleigh–Ritz procedure by the energy functions of the thick plate. The excellent accuracy and reliability of current solutions are demonstrated by numerical examples and comparisons with the results available in the literature. In addition, the influence of the foundation coefficients as well as the boundary restraint parameters is also analyzed, which can serve as the benchmark data for the future research technique. Huimin Liu, Fanming Liu, Xin Jing, Zhenpeng Wang, and Linlin Xia Copyright © 2017 Huimin Liu et al. All rights reserved. Field Tests to Investigate the Penetration Rate of Piles Driven by Vibratory Installation Sun, 21 May 2017 09:32:25 +0000 http://www.hindawi.com/journals/sv/2017/7236956/ Factors directly affecting the penetration rate of piles installed by vibratory driving technique are summarized and classified into seven aspects which are driving force, resistance, vibratory amplitude, energy consumption, speeding up at the beginning, pile plumbness keeping, and slowing down at the end, from the mechanism and engineering practice of the vibratory pile driving. In order to find out how these factors affect the penetration rate of the pile in three major actors of vibratory pile driving: (i) the pile to be driven, (ii) the selected driving system, and (iii) the imposed soil conditions, field tests on steel sheet piles driven by vibratory driving technique in different soil conditions are conducted. The penetration rates of three different sheet pile types having up to four different lengths installed using two different vibratory driving systems are documented. Piles with different lengths and types driven with or without clutch have different penetration rates. The working parameters of vibratory hammer, such as driving force and vibratory amplitude, have great influences on the penetration rate of the pile, especially at the later stages of the sinking process. Penetration rate of piles driven in different soil conditions is uniform because of the different penetration resistance including shaft friction and toe resistance. Zhaohui Qin, Longzhu Chen, Chunyu Song, and Lei Sun Copyright © 2017 Zhaohui Qin et al. All rights reserved. Ship Radiated Noise Recognition Using Resonance-Based Sparse Signal Decomposition Wed, 17 May 2017 06:46:44 +0000 http://www.hindawi.com/journals/sv/2017/6930605/ Under the complex oceanic environment, robust and effective feature extraction is the key issue of ship radiated noise recognition. Since traditional feature extraction methods are susceptible to the inevitable environmental noise, the type of vessels, and the speed of ships, the recognition accuracy will degrade significantly. Hence, we propose a robust time-frequency analysis method which combines resonance-based sparse signal decomposition (RSSD) and Hilbert marginal spectrum (HMS) analysis. First, the observed signals are decomposed into high resonance component, low resonance component, and residual component by RSSD, which is a nonlinear signal analysis method based not on frequency or scale but on resonance. High resonance component is multiple simultaneous sustained oscillations, low resonance component is nonoscillatory transients, and residual component is white Gaussian noises. According to the low-frequency periodic oscillatory characteristic of ship radiated noise, high resonance component is the purified ship radiated noise. RSSD is suited to noise suppression for low-frequency oscillation signals. Second, HMS of high resonance component is extracted by Hilbert-Huang transform (HHT) as the feature vector. Finally, support vector machine (SVM) is adopted as a classifier. Real audio recordings are employed in the experiments under different signal-to-noise ratios (SNRs). The experimental results indicate that the proposed method has a better recognition performance than the traditional method under different SNRs. Jiaquan Yan, Haixin Sun, En Cheng, Xiaoyan Kuai, and Xiaoliang Zhang Copyright © 2017 Jiaquan Yan et al. All rights reserved. Surrounding Rock Deformation Mechanism and Control Technology for Gob-Side Entry Retaining with Fully Mechanized Gangue Backfilling Mining: A Case Study Sun, 14 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/6085941/ To counter the technical difficulties faced by gob-side entry retaining (GER) under multiple complex mining geological conditions in China, this paper introduces a GER method with fully mechanized gangue backfilling mining. A similar materials simulation experiment was conducted to simulate the gob-backfilled GER process by using the similar model test system containing an independently developed horizontal pushing load device. The experimental results show that the compaction speed of the backfilling area (BFA) can be improved, and the main roof subsidence can be reduced by increasing the horizontal pushing load and reducing the attenuation rate of the stress in BFA. The designed roadside backfill body (RBB) containing a flexible cushion is adaptive to the given deformation of the main roof, thus reducing the stress concentration of the RBB. The field test results show that when a 2 MPa horizontal pushing load is exerted in the BFA, arranging a 200 mm high-water-material flexible cushion can cause the BFA to swiftly change to the compaction stage. After stabilized deformation, the roadway section satisfies the design and application requirements. The feasibility and rationality of the GER with the fully mechanized gangue backfilling mining are proved, providing a safe, efficient, and environmentally friendly mining method without using a coal pillar. Peng Gong, Zhanguo Ma, Ray Ruichong Zhang, Xiaoyan Ni, Fei Liu, and Zhimin Huang Copyright © 2017 Peng Gong et al. All rights reserved. Drivability Improvement Control for Vehicle Start-Up Applied to an Automated Manual Transmission Thu, 11 May 2017 10:42:13 +0000 http://www.hindawi.com/journals/sv/2017/5783527/ Drivability is the key factor for the automated manual transmission. It includes fast response to the driver’s demand and the driving comfort. This paper deals with a control methodology applied to an automated manual transmission vehicle for drivability enhancement during vehicle start-up phase. Based on a piecewise model of powertrain, a multiple-model predictive controller (mMPC) is designed with the engine speed, clutch disc speed, and wheel speed as the measurable input variables and the engine torque reference and clutch friction torque reference as the controller’s output variables. The model not only includes the clutch dynamic, the flexible shaft dynamic, but also includes the actuators’ delay character. Considering the driver’s intention, a slipping speed trajectory is generated based on the acceleration pedal dynamically. The designed control strategy is verified on a complete powertrain and longitudinal vehicle dynamic model with different driver’s torque demands. Danna Jiang, Ying Huang, Zhe Zuo, and Huan Li Copyright © 2017 Danna Jiang et al. All rights reserved. Corrigendum to “Fractal Model for Acoustic Absorbing of Porous Fibrous Metal Materials” Thu, 11 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/4606748/ Weihua Chen, Tianning Chen, Xiaopeng Wang, Jiuhui Wu, and Suobin Li Copyright © 2017 Weihua Chen et al. All rights reserved. A Blast-Resistant Method Based on Wave Converters with Spring Oscillator for Underground Structures Wed, 10 May 2017 10:10:56 +0000 http://www.hindawi.com/journals/sv/2017/2014726/ Researches on blast-resistant measures for underground structures such as tunnels and underground shopping malls are of great importance for their significant role in economic and social development. In this paper, a new blast-resistant method based on wave converters with spring oscillator for underground structures was put forward, so as to convert the shock wave with high frequency and high peak pressure to the periodic stress wave with low frequency and low peak pressure. The conception and calculation process of this new method were introduced. The mechanical characteristics and motion evolution law of wave converters were deduced theoretically. Based on the theoretical deduction results and finite difference software , the dynamic responses of the new blast-resistant structure and the traditional one were both calculated. Results showed that, after the deployment of wave converters, the peak absolute values of the bending moment, shear force, and axial force of the structure decreased generally, which verified the good blast-resistant effect of the new blast-resistant method. Yu Zhang, Yuanxue Liu, Runze Wu, Jichang Zhao, Ming Hu, and Yizhong Tan Copyright © 2017 Yu Zhang et al. All rights reserved. Field Testing and Analysis of Embankment Vibrations Induced by Heavy Haul Trains Wed, 10 May 2017 07:16:47 +0000 http://www.hindawi.com/journals/sv/2017/7410836/ This paper presents a field testing of track and ground-borne vibration generated by heavy haul trains. The test sites consisted of three embankments with height of 6.6, 8.1, and 11.9, respectively. The acceleration signals of the rail, sleeper, and embankment surface were recorded, and then the propagation characteristics of ground vibration with distance to track center were contrastively analyzed. The test results show that horizontal vibration was dominant for locations near the track but decreased rapidly and became comparable with the vertical levels as the distance from track center increases. The quasi-static excitation dominated the sleeper response, and the dominant frequency range was found in the low-frequency zone corresponding to the fundamental axle passage frequency. For embankment surface, another pronounced dominant frequency zone was observed between 30 and 80 Hz, which was attributed to the dynamic excitation. Moreover, these higher frequency components were more promptly attenuated than low-frequency ones. The reason that vibration levels generated by locomotive were greater than wagon was attributed to the different bogie suspension mode. The relationship between normalized PPV and distance from track center in doubly logarithmic scales can be expressed with exponential function, and the vibration attenuation rates were restrained with increasing the embankment height. Peng Li, Xianzhang Ling, Feng Zhang, Yan Li, and Yingying Zhao Copyright © 2017 Peng Li et al. All rights reserved. An Experimental Research on the Vibration of Surface-Textured Journal Bearings Tue, 09 May 2017 09:36:00 +0000 http://www.hindawi.com/journals/sv/2017/1261826/ Growing attention has been paid to surface texture owing to its significance in bearing lubrication, load capacity, and wear resistance. In this paper, research emphasis is placed on the influence of texture distributions on bearing vibration and rotor stability. With microfabrication techniques, three kinds of textures configurations (0–90° partial distribution, 0–160° partial distribution, and 0–160° full distribution) are designed and applied on the lower pad surface. The experiment of journal bearings is carried out. The experiment results show that there is a significant decrease in acceleration amplitude of the textured bearings compared to nontextured bearings. Furthermore, the 0–160° partially distributed journal bearings have better vibration damping effect than another two kinds of textures, which can be verified by the shaft center orbits, Fourier spectrums, and waterfall plots. Jian Dong, Xiaojing Wang, Jin Zhang, Xiaoqing Xiang, Zhou Nie, and Jiexi Shen Copyright © 2017 Jian Dong et al. All rights reserved. Numerical and Experimental Investigations on a Three-Dimensional Rod-Plate Impact Tue, 09 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/6720186/ There are a few numerical simulation methods available for impact problems. However, most numerical results are not validated experimentally. The goal of this paper is to examine how well the simulation results correspond to the physical reality. In this work, normal and oblique impacts of a hemispherical-tip rod on a square plate are investigated both numerically and experimentally. In the numerical approach, finite element method is used to discretize the contact bodies to describe the deformation precisely combined with the floating reference frame method to describe the rigid motion. In the experimental study, strain gauges and Laser Doppler Vibrometers are employed to measure the high-frequency impact responses. Detailed comparative studies between numerical and experimental results are performed. In the case of normal impact, great attention is given to investigate the influence of finite element mesh size on the simulation accuracy and a “Prediction-Refinement” discretization strategy is proposed for obtaining a mesh which is optimal for impact dynamics. In the case of oblique impact, the influence of Coulomb’s friction coefficient is investigated additionally. It shows that the numerical results are in good agreement with the experimental results for both normal and oblique impacts. Jianyao Wang, Zhuyong Liu, and Jiazhen Hong Copyright © 2017 Jianyao Wang et al. All rights reserved. Experimental Research on Seismic Performance of a New-Type of R/C Beam-Column Joints with End Plates Thu, 04 May 2017 10:20:19 +0000 http://www.hindawi.com/journals/sv/2017/3823469/ This paper presents a new-type of fabricated beam-column connections with end plates. The joint details are as follows: the concrete beams are connected to column by end plates and six high strength long bolts passing through the core area. In addition, in order to increase the stiffness and shear strength, stirrups are replaced by the steel plate hoop in the core zone. To examine the fail behavior of the fabricated beam-column connection specimens, a quasi-static test is conducted for nine full-scale models to obtain the hysteresis curves, skeleton curves, ductility, energy dissipation capacity, and other seismic indicators. The experimental results show that all specimens failed in bending in a malleable way with a beam plastic hinge and the hysteresis curves are excellently plump for the end plate connections. From the seismic indexes, the fabricated connection specimens exhibit better seismic performance, which can provide reference for the application of prefabricated frame structure in the earthquake area. Shufeng Li, Qingning Li, Haotian Jiang, Hao Zhang, and Lizhong Zhang Copyright © 2017 Shufeng Li et al. All rights reserved. Experimental and Numerical Study on Modal Dynamic Response of Water-Surrounded Slender Bridge Pier with Pile Foundation Tue, 02 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/4769637/ This paper presents an experimental program performed to study the effect of fluid-structure interaction on the modal dynamic response of water-surrounded slender bridge pier with pile foundation. A reduced scale slender bridge pier specimen is built and tested through forced vibration method. The vibration periods of the first four lateral modes, including the first two modes along -axis and the first two modes along -axis, are measured based on the specimen submerged by 16 levels of water and designated with 4 levels of tip mass. Three-dimensional (3D) finite-element models are established for the tested water-pier system and analyzed under various combined cases of water level and tip mass. Percentage increases of vibration periods with respect to dry vibration periods (i.e., vibration periods of the specimen without water) are determined as a function of water level and tip mass to evaluate the effect of fluid-structure interaction. The numerical results are successfully validated against the recorded test data. Based on the validated models, the modal hydrodynamic pressures are calculated to characterize the 3D distribution of hydrodynamic loads on the pier systems. The research provides a better illumination into the effect of fluid-structure interaction on the modal dynamic response of deepwater bridges. Yulin Deng, Qingkang Guo, and Lueqin Xu Copyright © 2017 Yulin Deng et al. All rights reserved. Analysis and Testing of Load Characteristics for Rotary-Percussive Drilling of Lunar Rock Simulant with a Lunar Regolith Coring Bit Sun, 30 Apr 2017 11:32:50 +0000 http://www.hindawi.com/journals/sv/2017/3012749/ Based on an optimized lunar regolith coring bit (LRCB) configuration, the load characteristics of rotary-percussive drilling of lunar rock simulant in a laboratory environment are analyzed to determine the effects of the drilling parameters (the rotational velocity, the penetration rate, and the percussion frequency) on the drilling load. The process of rotary drilling into lunar rock using an LRCB is modeled as an interaction between an elemental blade and the rock. The rock’s fracture mechanism during different stages of the percussive mechanism is analyzed to create a load forecasting model for the cutting and percussive fracturing of rock using an elemental blade. Finally, a model of the load on the LRCB is obtained from the analytic equation for the bit’s cutting blade distribution; experimental verification of the rotary-impact load characteristics for lunar rock simulant with different parameters is performed. The results show that the penetrations per revolution (PPR) are the primary parameter influencing the drilling load. When the PPR are fixed, increasing the percussion frequency reduces the drilling load on the rock. Additionally, the variation pattern of the drilling load of the bit is in agreement with that predicted by the theoretical model. This provides a research basis for subsequent optimization of the drilling procedure and online recognition of the drilling process. Peng Li, Hui Zhang, Shengyuan Jiang, and Weiwei Zhang Copyright © 2017 Peng Li et al. All rights reserved. Full Vehicle Vibration and Noise Analysis Based on Substructure Power Flow Sun, 30 Apr 2017 08:22:19 +0000 http://www.hindawi.com/journals/sv/2017/8725346/ Combining substructure and power flow theory, in this paper an external program is written to control MSC. Nastran solution process and the substructure frequency response are also formulated accordingly. Based on a simple vehicle model, characteristics of vibration, noise, and power flow are studied, respectively. After being compared with the result of conventional FEM (finite element method), the new method is confirmed to be feasible. When it comes to a vehicle with the problem of low-frequency noise, finite element models of substructures for vehicle body and chassis are established, respectively. In addition, substructure power flow method is also employed to examine the transfer characteristics of multidimensional vibration energy for the whole vehicle system. By virtue of the adjustment stiffness of drive shaft support and bushes at rear suspension lower arm, the vehicle interior noise is decreased by about 3 dB when the engine speed is near 1050 rpm and 1650 rpm in experiment. At the same time, this method can increase the computation efficiency by 78%, 38%, and 98% when it comes to the optimization of chassis structure, body structure, and vibration isolation components, respectively. Zhien Liu, Shuai Yuan, Shenghao Xiao, Songze Du, Yan Zhang, and Chihua Lu Copyright © 2017 Zhien Liu et al. All rights reserved. Bending Vibration Suppression of a Flexible Multispan Shaft Using Smart Spring Support Sun, 30 Apr 2017 08:02:22 +0000 http://www.hindawi.com/journals/sv/2017/7859164/ Because the flexible multispan shaft in large machines often rotates at supercritical speed, it is desirable to find ways to suppress the resulting bending vibration. In this paper, a novel type of support structure is proposed and investigated, which can suppress the bending vibration using dry friction. This approach is called Smart Spring support (SMSS). A dynamic model for the multispan shaft with SMSS is developed. The relationship between the vibration suppression effect and the control parameters of the SMSS is obtained through a numerical example involving a helicopter tail drive shaft. A structure of the SMSS is designed and examined with a rotor test. The results demonstrate that the SMSS has a significant effect on bending vibration suppression of flexible multispan shafts. The vibration-reduction ratio of the peak amplitude reaches 57.2% in the numerical example and 45.2% in the rotor test. Bo Peng, Rupeng Zhu, Miaomiao Li, and Ziyang Tang Copyright © 2017 Bo Peng et al. All rights reserved. Shaking-Table Tests for Immersed Tunnels at Different Sites Wed, 26 Apr 2017 10:41:16 +0000 http://www.hindawi.com/journals/sv/2017/2546318/ Immersed tunnels are typically built in areas subjected to ground motion. Therefore, an evaluation of the seismic performance of the soil-tunnel system is essential. A series of shaking-table tests was conducted to study the influences of the site soil and overlying water layer on the seismic responses of soil deposits and an immersed tunnel. Detailed information on the experiment setup is provided with special focus on the similitude relationship, fabrication of the model system, measurement setup, and loading procedures for a simulation of the seismic waves. Three groups of tests at different sites in dry sand, saturated sand, and saturated sand with an overlying water layer were carried out using the same seismic excitations. The seismic responses of the soil deposits and the dynamic responses of the tunnel model were obtained. The experiment results indicate that, when considering only horizontal earthquake excitations, soil liquefaction significantly influences the propagation of seismic waves and the dynamic responses of the tunnel, whereas the water layer has no obvious effects on the dynamic performance of the ground or tunnel. Furthermore, the acceleration responses of the tunnel elements were analyzed qualitatively, and the joints are deemed important elements in an antiseismic immersed tunnel design. Xinjun Cheng, Liping Jing, Jie Cui, Yongqiang Li, and Rui Dong Copyright © 2017 Xinjun Cheng et al. All rights reserved. Scaling Mode Shapes in Output-Only Structure by a Mass-Change-Based Method Wed, 26 Apr 2017 08:27:03 +0000 http://www.hindawi.com/journals/sv/2017/2617534/ A mass-change-based method based on output-only data for the rescaling of mode shapes in operational modal analysis (OMA) is introduced. The mass distribution matrix, which is defined as a diagonal matrix whose diagonal elements represent the ratios among the diagonal elements of the mass matrix, is calculated using the unscaled mode shapes. Based on the theory of null space, the mass distribution vector or mass distribution matrix is obtained. A small mass with calibrated weight is added to a certain location of the structure, and then the mass distribution vector of the modified structure is estimated. The mass matrix is identified according to the difference of the mass distribution vectors between the original and modified structures. Additionally, the universal set of modes is unnecessary when calculating the mass distribution matrix, indicating that modal truncation is allowed in the proposed method. The mass-scaled mode shapes estimated in OMA according to the proposed method are compared with those obtained by experimental modal analysis. A simulation is employed to validate the feasibility of the method. Finally, the method is tested on output-only data from an experiment on a five-storey structure, and the results confirm the effectiveness of the method. Liangliang Yu and Hanwen Song Copyright © 2017 Liangliang Yu and Hanwen Song. All rights reserved. Numerical Simulation of Blast Vibration and Crack Forming Effect of Rock-Anchored Beam Excavation in Deep Underground Caverns Sun, 23 Apr 2017 08:32:55 +0000 http://www.hindawi.com/journals/sv/2017/1812080/ Aiming at surrounding rock damage induced by dynamic disturbance from blasting excavation of rock-anchored beam in rock mass at moderate or far distance in underground cavern, numerical model of different linear charging density and crustal stress in underground cavern is established by adopting dynamic finite element software based on borehole layout, charging, and rock parameter of the actual situation of a certain hydropower station. Through comparison in vibration velocity, contour surface of rock mass excavation, and the crushing extent of excavated rock mass between calculation result and field monitoring, optimum linear charging density of blast hole is determined. Studies are also conducted on rock mass vibration in moderate or far distance to blasting source, the damage of surrounding rock in near-field to blasting source, and crushing degree of excavated rock mass under various in situ stress conditions. Results indicate that, within certain range of in situ stress, the blasting vibration is independent of in situ stress, while when in situ stress is increasing above certain value, the blasting vibration velocity will be increasing and the damage of surrounding rock and the crushing degree of excavated rock mass will be decreasing. XinPing Li, JunHong Huang, Yi Luo, Qian Dong, YouHua Li, Yong Wan, and TingTing Liu Copyright © 2017 XinPing Li et al. All rights reserved. Dynamic Modeling and Characteristic Analysis of Floating Raft System with Attached Pipes Thu, 20 Apr 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/9135715/ The vibration transmission performance of a floating raft system with attached pipes is investigated in this paper. The frequency response function-based (FRF-based) substructure synthesizing method whose accuracy has been verified by numerical simulations and experiment is applied for modeling the system. The power flow through the transmission paths is used for exploring the additional vibration transmission path provided by the attached pipes. The results show that the existence of the additional transmission paths caused by the pipes breaks the symmetries of the system, which leads to the enhancement of the coupling between each substructure. Consequently, it degrades the vibration isolation performance of the raft system. Moreover, a parametric study is performed to investigate the effects on the mean-square velocity of the hull of the attached pipes, which gives a brief guideline for designing the attached pipes. Longlong Ren, Yang Li, Xiuchang Huang, and Hongxing Hua Copyright © 2017 Longlong Ren et al. All rights reserved. Predicting the Pullout Capacity of Small Ground Anchors Using Nonlinear Integrated Computing Techniques Wed, 19 Apr 2017 09:19:58 +0000 http://www.hindawi.com/journals/sv/2017/2601063/ This study investigates predicting the pullout capacity of small ground anchors using nonlinear computing techniques. The input-output prediction model for the nonlinear Hammerstein-Wiener (NHW) and delay inputs for the adaptive neurofuzzy inference system (DANFIS) are developed and utilized to predict the pullout capacity. The results of the developed models are compared with previous studies that used artificial neural networks and least square support vector machine techniques for the same case study. The in situ data collection and statistical performances are used to evaluate the models performance. Results show that the developed models enhance the precision of predicting the pullout capacity when compared with previous studies. Also, the DANFIS model performance is proven to be better than other models used to detect the pullout capacity of ground anchors. Mosbeh R. Kaloop, Jong Wan Hu, and Emad Elbeltagi Copyright © 2017 Mosbeh R. Kaloop et al. All rights reserved. Analysis of Dynamic Coupling Characteristics of the Slope Reinforced by Sheet Pile Wall Wed, 19 Apr 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/9043518/ Large deformation of slope caused by earthquake can lead to the loss of stability of slope and its retaining structures. At present, there have been some research achievements about the slope reinforcement of stabilizing piles. However, due to the complexity of the structural system, the coupling relationship between soil and pile is still not well understood. Hence it is of great necessity to study its dynamic characteristics further. In view of this, a numerical model was established by in this paper, and the deformation and stress nephogram of sheet pile wall in peak ground motion acceleration (PGA) at 0.1 g, 0.2 g, and 0.4 g were obtained. Through the analysis, some conclusions were obtained. Firstly, based on the nephogram of motion characteristics and the positions of the slip surface and the retaining wall, the reinforced slope can be divided into 6 sections approximatively, namely, the sliding body parts of A, B, C, D, and E and the bedrock part F. Secondly, the deformation and stress distributions of slope reinforced by sheet pile wall were carefully studied. Based on the results of deformation calculation from time history analysis, the interaction force between structure and soil can be estimated by the difference of peak horizontal displacements, and the structure-soil coupling law under earthquake can be studied by this approach. H. L. Qu, H. Luo, L. Liu, and Y. Liu Copyright © 2017 H. L. Qu et al. All rights reserved. Structural Characteristics of Rotate Vector Reducer Free Vibration Tue, 18 Apr 2017 07:18:37 +0000 http://www.hindawi.com/journals/sv/2017/4214370/ For RV reducer widely used in robots, vibration significantly affects its performance. A lumped parameter model is developed to investigate free vibration characteristics without and with gyroscopic effects. The dynamic model considers key factors affecting vibration such as involute and cycloid gear mesh stiffness, crankshaft bending stiffness, and bearing stiffness. For both nongyroscopic and gyroscopic systems, free vibrations are examined and compared with each other. Results reveal the specific structure of vibration modes for both systems, which results from symmetry structure of RV reducer. According to vibration of the central components, vibration modes of two systems can be classified into three types, rotational, translational, and planetary component modes. Different from nongyroscopic system, the eigenvalues with gyroscopic effects are complex-valued and speed-dependent. The eigenvalue for a range of carrier speeds is obtained by numerical simulation. Divergence and flutter instability is observed at speeds adjacent to critical speeds. Furthermore, the work studies effects of key factors, which include crankshaft eccentricity and the number of pins, on eigenvalues. Finally, experiment is performed to verify the effectiveness of the dynamic model. The research of this paper is helpful for the analysis on free vibration and dynamic design of RV reducer. Chuan Chen and Yuhu Yang Copyright © 2017 Chuan Chen and Yuhu Yang. All rights reserved. Numerical Modelling of Building Vibrations due to Railway Traffic: Analysis of the Mitigation Capacity of a Wave Barrier Tue, 18 Apr 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/4813274/ Transmission of train-induced vibrations to buildings located in the vicinity of the track is one of the main negative externalities of railway transport, since both human comfort and the adequate functioning of sensitive equipment may be compromised. In this paper, a 3D FEM model is presented and validated with data from a real track stretch near Barcelona, Spain. Furthermore, a case study is analyzed as an application of the model, in order to evaluate the propagation and transmission of vibrations induced by the passage of a suburban train to a nearby 3-storey building. As a main outcome, vertical vibrations in the foundation slab are found to be maximum in the corners, while horizontal vibrations keep constant along the edges. The propagation within the building structure is also studied, concluding that vibrations invariably increase in their propagation upwards the building. Moreover, the mitigation capacity of a wave barrier acting as a source isolation is assessed by comparing vibration levels registered in several points of the building structure with and without the barrier. In this regard, the wave barrier is found to effectively reduce vibration in both the soil and the structure. Fran Ribes-Llario, Silvia Marzal, Clara Zamorano, and Julia Real Copyright © 2017 Fran Ribes-Llario et al. All rights reserved. Study on the Correlation of Vibration Properties and Crack Index in the Health Assessment of Tunnel Lining Tue, 18 Apr 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/5497457/ This paper examines the correlation of vibration properties and crack index of tunnel lining in evaluating risk of collapsing. The visual inspection method, which was widely used, was not reliable enough as the stability of tunnel lining was influenced by the voids and the cracks that were invisible. A new method for the health assessment of tunnel lining was proposed, which can evaluate the whole structural condition according to the vibration properties of tunnel lining. A series of field tests were conducted to evaluate the validity of this new method and to make a comparative analysis with the visual inspection test results. The resultant average spectrum (RAS) of tunnel lining was identified according to the acceleration data of ambient vibration test of Hidake Tunnel in Japan. The tunnel lining crack index (TCI) was also obtained by digital visual inspection test. The correlation between the vibration characteristics and the crack index of tunnel lining was confirmed. However, the voids and the cracks on the inside of the lining were neglected in visual inspection test, which could pose a serious threat to tunnel safety. The vibration measurements by seismometer are an effective way to evaluate the global stability of tunnel lining. Xuezhen Wu, Yujing Jiang, Kusaba Masaya, Tetsuya Taniguchi, and Takahide Yamato Copyright © 2017 Xuezhen Wu et al. All rights reserved. Vibration Characteristics for Moving Printing Membrane with Variable Density along the Lateral Direction Tue, 18 Apr 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/2968705/ The vibration model of moving membrane with variable density distribution is established, and the density distribution of the moving membrane varies along the lateral direction. The transverse vibration differential equations of moving membrane are established based on D’Alembert’s principle and discretized by using the differential quadrature method (DQM). The relationships of the first three dimensionless complex frequencies between dimensionless speed, density coefficient, and tension ratio of the membrane are analyzed by numerical calculation. The effects of the density coefficient and the tension ratio on transverse vibration characteristics of the membrane are investigated. The relationship between density coefficient and critical speed is obtained. The numerical results show that the density coefficient and the tension ratio have important influence on the stability of moving membrane. So the study provides a theoretical basis for improving the working stability of the membrane in the high-speed printing process. Mingyue Shao, Jimei Wu, Yan Wang, Qiumin Wu, and Yuan Chen Copyright © 2017 Mingyue Shao et al. All rights reserved. Rolling Bearing Reliability Assessment via Kernel Principal Component Analysis and Weibull Proportional Hazard Model Sun, 16 Apr 2017 00:00:00 +0000 http://www.hindawi.com/journals/sv/2017/6184190/ Reliability assessment is a critical consideration in equipment engineering project. Successful reliability assessment, which is dependent on selecting features that accurately reflect performance degradation as the inputs of the assessment model, allows for the proactive maintenance of equipment. In this paper, a novel method based on kernel principal component analysis (KPCA) and Weibull proportional hazards model (WPHM) is proposed to assess the reliability of rolling bearings. A high relative feature set is constructed by selecting the effective features through extracting the time domain, frequency domain, and time-frequency domain features over the bearing’s life cycle data. The kernel principal components which can accurately reflect the performance degradation process are obtained by KPCA and then input as the covariates of WPHM to assess the reliability. An example was conducted to validate the proposed method. The differences in manufacturing, installation, and working conditions of the same type of bearings during reliability assessment are reduced after extracting relative features, which enhances the practicability and stability of the proposed method. Fengtao Wang, Xutao Chen, Bosen Dun, Bei Wang, Dawen Yan, and Hong Zhu Copyright © 2017 Fengtao Wang et al. All rights reserved.