scholarly journals Baseline Correction of Acceleration Data Based on a Hybrid EMD–DNN Method

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6283
Author(s):  
Zengshun Chen ◽  
Jun Fu ◽  
Yanjian Peng ◽  
Tuanhai Chen ◽  
LiKai Zhang ◽  
...  
Keyword(s):  
Mean Square Error ◽  
Shaking Table Test ◽  
Time History ◽  
Shaking Table ◽  
Frequency Noise ◽  
Baseline Correction ◽  
Multiple Time ◽  
Mean Square ◽  
Displacement Response ◽  
Seismic Engineering

Measuring displacement response is essential in the field of structural health monitoring and seismic engineering. Numerical integration of the acceleration signal is a common measurement method of displacement data. However, due to the circumstances of ground tilt, low-frequency noise caused by instruments, hysteresis of the transducer, etc., it would generate a baseline drift phenomenon in acceleration integration, failing to obtain an actual displacement response. The improved traditional baseline correction methods still have some problems, such as high baseline correction error, poor adaptability, and narrow application scope. This paper proposes a deep neural network model based on empirical mode decomposition (EMD–DNN) to solve baseline correction by removing the drifting trend. The feature of multiple time sequences that EMD obtains is extracted via DNN, achieving the real displacement time history of prediction. In order to verify the effectiveness of the proposed method, two natural waves (EL centro wave, Taft wave) and one Artificial wave are selected to test in a shaking table test. Comparing the traditional methods such as the least squares method, EMD, and DNN method, EMD–DNN has the best baseline correction effect in terms of the evaluation indexes: Mean Absolute Error (MAE), Mean Square Error (MSE), Root Mean Square Error (RMSE), and degree of fit (R-Square).

Shaking Table Test Study of Reinforced Concrete Shear Wall Structure

2017 ◽  
Vol 865 ◽  
pp. 306-312
Author(s):  
Zheng Li ◽  
Heng Zhou ◽  
Li Qin
Keyword(s):  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
Shaking Table Test ◽  
Time History ◽  
Shear Wall ◽  
Shaking Table ◽  
Wall Structure ◽  
Model Structure ◽  
Fixed Base ◽  
Time History Response

A reduced-scale model of 7-story reinforced concrete shear wall structure is made. Shaking-table test of the model is carried out. Two test conditions are considered. In the first condition, fixed base is used. In another condition, soil structure interaction is considered. According to the experimental results, the dynamic characteristic and seismic performance of shear wall structure is studied. The acceleration time history response of model structure is obtained. Based on the time-history response, the dynamic characteristics of model structure are studied by spectrum analysis. The Finite Element Model of actural structure is established by ANSYS. The dynamic characteristics and seismic performance of actural structure are studied. By comparing the experiment results and numerical analysis results under the fixed-base condition, the rationality of the ANSYS model and numerical analysis method of are verified.

scholarly journals Experimental and Numerical Studies on Sloshing Dynamics of PCS Water Tank of Nuclear Island Building

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaojun Li ◽  
Chenning Song ◽  
Guoliang Zhou ◽  
Chao Wei ◽  
Ming Lu
Keyword(s):  
Shaking Table Test ◽  
Cooling System ◽  
Damping Ratio ◽  
Time History ◽  
Hydrodynamic Pressure ◽  
Test Method ◽  
Shaking Table ◽  
Water Tank ◽  
Scaled Model ◽  
Sloshing Dynamics

Water tank is one important component of passive containment cooling system (PCS) of nuclear island building. The sloshing frequency of water is much less than structure frequency and large-amplitude sloshing occurs easily when subjected to seismic loadings. Therefore, the sloshing dynamics and fluid-structure interaction (FSI) effect of water tank should be considered when the dynamic response of nuclear island building is analyzed. A 1/16 scaled model was designed and the shaking table test was done, in which the hydrodynamic pressure time histories and attenuation data of wave height were recorded. Then the sloshing frequencies and 1st sloshing damping ratio were recognized. Moreover, modal analysis and time history analysis of numerical model were done by ADINA software. By comparing the sloshing frequencies and hydrodynamic pressures, it is proved that the test method is reasonable and the formulation of potential-based fluid elements (PBFE) can be used to simulate FSI effect of nuclear island building.

Shaking Table Test for Base-Isolated Nuclear Island Structure Model

2017 ◽  
Author(s):  
Yang Jie ◽  
Li ShaoPing ◽  
Yuan Fang ◽  
Xia ZuFeng ◽  
Huang XiaoLin
Keyword(s):  
Shaking Table Test ◽  
Three Dimensional ◽  
Time History ◽  
Response Spectra ◽  
Shaking Table ◽  
Nonlinear Time History Analysis ◽  
Earthquake Simulation ◽  
Maximum Displacement ◽  
Island Structure ◽  
Reduced Scale

In this paper, the base-isolated design of Nuclear Island structure will be introduced, including the general requirement and the goal of the base-isolated design. Integrated assessment has been performed for the base-isolated design of Nuclear Island structure in the earthquake 0.6g. A series of nonlinear time-history analysis were performed to predict the maximum displacement and acceleration of the isolation layer, the maximum stress of the isolation units, and the floor response spectra of each story of the superstructure in the earthquake 0.6g, considering the realistic mechanical properties and the layout of the isolators. In order to provide realistic data to validate the numerical method, a reduced-scale earthquake simulation of base-isolated nuclear structure on a shaking table was carried out. The study was primarily focused on the response of superstructure and the isolation unit. The dynamic characteristic was examined, together with the vibration acceleration and displacement under different levels of seismic wave. The test results of a reduced-scale nuclear island model previously tested on a shaking table were compared with three-dimensional finite element simulation results. The results of this study provide the technical basis for the base-isolated design of Nuclear Island structure.

scholarly journals Dynamic Response Characteristics of Aeolian Sediment along Sichuan-Tibet Railway

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Kan Han ◽  
Chunxiao Xue
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Shaking Table Test ◽  
Soil Layer ◽  
Time History ◽  
Surface Displacement ◽  
Shaking Table ◽  
Aeolian Sand ◽  
Response Characteristics ◽  
Dynamic Response Characteristics

In order to reduce the damage of liquefaction of aeolian sand along the Sichuan-Tibet railway, the dynamic response characteristics of saturated aeolian sand in the study area were discussed by using shaking table test. The results show that the macroscopic characteristics of saturated aeolian sand in the study area are subsidence, water flow and fracture. The displacement time history shows that the surface displacement increases with increasing the input ground motion acceleration. When the acceleration is small (0.1g), the vibration in the soil layer has an obvious tendency to enlarge continuously from bottom to top. With the increase of the acceleration (0.2g), the amplification trend basically disappeared. When the acceleration increases to 0.3g, the ground motion increases first and then decreases.

Study on Piping Response Under Multiple Excitation: Part 2 — Validation for Multiple Excitation Analysis of Piping

2013 ◽  
Author(s):  
Satoru Kai ◽  
Tomoyoshi Watakabe ◽  
Naoaki Kaneko ◽  
Kunihiro Tochiki ◽  
Makoto Moriizumi ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Nuclear Power ◽  
Response Spectrum ◽  
Time History ◽  
Response Spectra ◽  
Shaking Table ◽  
Response Analysis ◽  
Multiple Time ◽  
Floor Response Spectra

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many points. As the piping is excited by multiple-inputs from the supporting points during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few experiments involving such multiple excitation have been performed to verify the validity of multiple excitation analysis. Therefore, analysis of the seismic design of piping in Japan is performed by the enveloped Floor Response Spectrum (FRS), which covers all floor response spectra at all supporting points. The piping response estimated by enveloped FRS is conservative in most cases compared with the actual seismic response by multiple excitations. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and to verify the validity of the analytical method by multiple excitation test. This paper reports the validation results of the multiple-excitation analysis of piping compared with the results of the multiple excitations shaking test using triple uni-axial shaking table and a 3-dimensional piping model (89.1mm diameter and 5.5mm thickness). Three directional moments from the analysis and the shaking test were compared on the validation. As the result, it is confirmed that the analysis by multiple time history excitation corresponds with the test result.

scholarly journals Experimental Verification of Methods for Converting Acceleration Data in High-Rise Buildings into Displacement Data by Shaking Table Test

2019 ◽  
Vol 9 (8) ◽  
pp. 1653 ◽  
Author(s):  
Han ◽  
Park ◽  
Park ◽  
Kim ◽  
Baek
Keyword(s):  
Transfer Function ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Model Building ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Frequency Noise ◽  
High Speed Imaging ◽  
High Rise ◽  
Acceleration Data

When diagnosing damage to high-rise buildings during earthquakes, it is necessary to measure the displacement of each story. However, with respect to accuracy and cost, it is most reasonable to convert acceleration into displacement. In this study, shake table testing was carried out to verify the conversion methods, converting the acceleration data measured in a high-rise building into velocity and displacement. In the shaking table test, the displacement of a 10-story model building under strong motion was measured using high-speed imaging devices. High-speed images were taken at 1000 frames per second, reflecting the dynamic behavior of the model building. Then, this displacement was compared with the displacement obtained by processing the acceleration data. This study applied three methods for correcting and converting acceleration into velocity and displacement. Method 1 used the transfer function, H2ω, which reflects the dynamic characteristics of the system. The displacements converted by this method showed the lowest accuracy, because the transfer function depends on the dynamic characteristics of the structure. Method 2 used the cosine Fourier transform for baseline correction, and the discrete input data are calculated as the sum of the cosine functions. Method 3 used the least-squares fitting in the first step to remove the linear drift in the acceleration and applied the high-pass Butterworth filter. The displacements converted by Method 2 were the most reliable, and were close to the displacements measured in the shaking table test. However, the response of high-rise buildings is affected by low- and high-frequency noise. It is necessary to further investigate the limitations and applicability of the conversion methods for providing reliable displacement of the building.

Shaking Table Test of Underground Pipeline under Three Dimension Seismic Excitation – Numerical Simulation

2014 ◽  
Vol 919-921 ◽  
pp. 960-964 ◽  
Author(s):  
Xiao Fu ◽  
Jun Wei Bi ◽  
Zhi Jia Wang ◽  
Chang Wei Yang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Seismic Response ◽  
Shaking Table Test ◽  
Time History ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Underground Pipeline ◽  
Three Dimension ◽  
Seismic Structure

Based on the design of the large-scale shaking table test of an underground pipeline under three dimension seismic excitation, the dynamic response of the soil-structure is analyzed by using ANSYS. In the numerical simulation, Drucker-Prager constitutive model is adopted to simulate the soil, the interface between soil and pipeline are simulated with zero thickness contact elements, size effects of test box are diminished by defining viscoelastic boundary around soil, the acceleration time history curve of the original earthquake wave is compressed and processed according to using the model scale similarity and energy duration which is presented by Trifunac-Brady [1] , and then the characteristic of seismic response of the pipeline can be found. The results show that the top of pipeline is the seismic response intense regional, deformation displacements of the central areas at the bottom and top of pipeline are always larger than others, the entrance and exit are the weak positions of anti-seismic structure; moreover, the dynamic response and interactions of soil-pipeline in the model experiment can be more accurately simulated by the methods presented in the paper. Thus, it can be served as reference for the design and construction of subsurface structures.

Experimental and Simulation Study of a Hybrid Frame Structure with Viscous Dampers

2012 ◽  
Vol 446-449 ◽  
pp. 894-899
Author(s):  
Hong Mei Zhang ◽  
Xi Lin Lu ◽  
Chun Guang Meng
Keyword(s):  
Shaking Table Test ◽  
Time History ◽  
Shaking Table ◽  
Frame Structure ◽  
Nonlinear Time History Analysis ◽  
Seismic Action ◽  
Test Model ◽  
Viscous Dampers ◽  
Scaled Model ◽  
Nonlinear Simulation

A Concrete-filled Rectangular Steel Tube (CRST) frame structure is studied in this paper by shaking table model test and nonlinear simulation. A number of viscous dampers are employed to insure the function of the building especially under seismic action for some of the main vertical elements of the building are not continuous. A shaking table test of a scaled model was conducted under different earthquake waves to investigate the structural behavior. And the nonlinear time-history analysis for the shaking table test model was also carried out by finite element analysis program according to the shaking table test. The simulation model was constructed in accordance with the tested specimen and the simulation effect was then validated by the tested results. To sum up, (1) there are no obvious weak stories on the damping equipped structure; (2) the dampers can reduce the displacement of the irregular to a certain degree.

Seismic Behavior of Steel Moment Frames with Mechanical Hinge Beam-to-Column Connections

2020 ◽  
Vol 20 (06) ◽  
pp. 2040005
Author(s):  
Han Peng ◽  
Jinping Ou ◽  
Andreas Schellenberg ◽  
Frank Mckenna ◽  
Stephen Mahin
Keyword(s):  
Seismic Behavior ◽  
Shaking Table Test ◽  
Plastic Hinge ◽  
Time History ◽  
Shaking Table ◽  
Base Shear ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Moment Frame ◽  
Steel Moment Frame

This paper presents an investigation on the seismic behavior of steel moment frames with mechanical hinge beam-to-column connections. The connection uses a mechanical hinge to carry shear force and a pair of buckling-restrained steel plates bolted to the beam flange to transfer bending moment. The moment-rotation behavior of the connection was theoretically studied. A nonlinear numerical model for steel moment frames under strong earthquakes was developed and validated using a shaking table test of an 18-story steel moment frame at the E-Defense facility. Then, nonlinear static and time-history analyses were conducted to compare the seismic behavior of a conventional steel moment frame and three innovative steel frames equipped mechanical hinge connections in terms of roof displacement, base shear, inter-story drift ratio, and plastic hinge rotation.

scholarly journals Seismic Response of Flat Ground and Slope Models through 1 g Shaking Table Tests and Numerical Analysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1875
Author(s):  
Yong Jin ◽  
Hoyeon Kim ◽  
Daehyeon Kim ◽  
Yonghee Lee ◽  
Haksung Kim
Keyword(s):  
Numerical Analysis ◽  
Seismic Waves ◽  
Shaking Table Test ◽  
Time History ◽  
Shaking Table ◽  
Numerical Analyses ◽  
Shaking Table Tests ◽  
Shear Box ◽  
Laminar Shear ◽  
Flat Ground

In order to verify the reliability of numerical analysis, a series of 1 g shaking table tests for flat ground and slope were conducted using a laminar shear box subjected to different seismic waves. Firstly, numerical analyses, using the DEEPSOIL and ABAQUS software, were done to compare the results of flat ground experiments. After that, finite element analyses with ABAQUS were conducted to compare the results of slope experiments. For numerical analyses, considering the influence of the boundary, the concept of adjusted elastic modulus was proposed to improve the simulation results. Based on the analyses, it is found that in terms of acceleration-time history and spectral acceleration, the numerical analysis results are in good agreement with the experiment results. This implies that numerical analysis can capture the dynamic behavior of soil under 1 g shaking table test conditions.

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