scholarly journals Dynamic Analysis of a Spring-Asphalt Three-Dimensional Isolation System Based on Cyclic Simple Shear and Shaking Table Tests

2020 ◽  
Vol 10 (18) ◽  
pp. 6530
Author(s):  
Shouping Shang ◽  
Zhen Wang
Keyword(s):  
Simple Shear ◽  
Low Cost ◽  
Three Dimensional ◽  
Least Square Method ◽  
Least Square ◽  
Shaking Table ◽  
Loading Frequency ◽  
Damping Properties ◽  
Shaking Table Tests ◽  
Isolation System

Damping is one of the important issues related to isolated structures, including the newly proposed low-cost spring-asphalt isolation system. In this study, the damping properties of the system in terms of displacement dependence, frequency dependence and temperature dependence were studied by a cyclic simple shear experiment. Then, the direct least-square method was used to identify the damping properties from the experimental data. Furthermore, to validate the effectiveness of the damping device, a modal analysis was conducted based on multi-dimensional shaking table tests. The results indicate that (1) the hysteretic curves are similar to an ellipse, which means that the asphalt shows characteristics of viscoelastic materials; (2) the damping properties are positively related to the loading frequency and inversely related to the temperature and displacement; and (3) asphalt can provide adequate damping and reduce the displacements of the superstructure by nearly half. On the basis of the experimental test results, an analysis of the modal information with multi-dimensional input is also presented.

scholarly journals Low-cost hybrid design of masonry structures for developing countries: Shaking table tests

2021 ◽  
Vol 146 ◽  
pp. 106675
Author(s):  
Anastasios Tsiavos ◽  
Anastasios Sextos ◽  
Andreas Stavridis ◽  
Matt Dietz ◽  
Luiza Dihoru ◽  
...  
Keyword(s):  
Developing Countries ◽  
Low Cost ◽  
Shaking Table ◽  
Hybrid Design ◽  
Masonry Structures ◽  
Shaking Table Tests

scholarly journals Numerical Exploration via Least Squares Estimation on Three Dimensional MHD Yield Exhibiting Nanofluid Model with Porous Stretching Boundaries

2021 ◽  
Vol 5 (4) ◽  
pp. 167
Author(s):  
Tamour Zubair ◽  
Muhammad Usman ◽  
Umar Nazir ◽  
Poom Kumam ◽  
Muhammad Sohail
Keyword(s):  
Differential Equations ◽  
Numerical Study ◽  
Nonlinear Partial Differential Equations ◽  
Three Dimensional ◽  
Least Square Method ◽  
Least Square ◽  
Comparison Study ◽  
Nano Fluid ◽  
Complicated Geometry ◽  
Maple Code

The numerical study of a three-dimensional magneto-hydrodynamic (MHD) Casson nano-fluid with porous and stretchy boundaries is the focus of this paper. Radiation impacts are also supposed. A feasible similarity variable may convert a verbalized set of nonlinear “partial” differential equations (PDEs) into a system of nonlinear “ordinary” differential equations (ODEs). To investigate the solutions of the resulting dimensionless model, the least-square method is suggested and extended. Maple code is created for the expanded technique of determining model behaviour. Several simulations were run, and graphs were used to provide a thorough explanation of the important parameters on velocities, skin friction, local Nusselt number, and temperature. The comparison study attests that the suggested method is well-matched, trustworthy, and accurate for investigating the governing model’s answers. This method may be expanded to solve additional physical issues with complicated geometry.

scholarly journals Low Cost Frictional Seismic Base-Isolation of Residential New Masonry Buildings in Developing Countries: A Small Masonry House Case Study

2017 ◽  
Vol 11 (1) ◽  
pp. 1026-1035 ◽  
Author(s):  
Ahmad Basshofi Habieb ◽  
Gabriele Milani ◽  
Tavio Tavio ◽  
Federico Milani
Keyword(s):  
Finite Element ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
Low Cost ◽  
Element Model ◽  
Shaking Table ◽  
Fe Model ◽  
Isolation System ◽  
Finite Element Software ◽  
Non Linear

Introduction:An advanced Finite Element model is presented to examine the performance of a low-cost friction based-isolation system in reducing the seismic vulnerability of low-class rural housings. This study, which is mainly numerical, adopts as benchmark an experimental investigation on a single story masonry system eventually isolated at the base and tested on a shaking table in India.Methods:Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ for the friction coefficient, which was experimentally obtained through the aforementioned research. The FE model adopted here is based on a macroscopic approach for masonry, which is assumed as an isotropic material exhibiting damage and softening. The Concrete damage plasticity (CDP) model, that is available in standard package of ABAQUS finite element software, is used to determine the non-linear behavior of the house under non-linear dynamic excitation.Results and Conclusion:The results of FE analyses show that the utilization of friction isolation systems could much decrease the acceleration response at roof level, with a very good agreement with the experimental data. It is also found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is that there was little damage appearing in systems with frictional isolation during numerical simulations. Meanwhile, a severe state of damage was clearly visible for the system without isolation.

scholarly journals Polymeric Bearings as a new base isolation system suitable for mitigating machine-induced vibrations

2018 ◽  
Vol 211 ◽  
pp. 17001 ◽  
Author(s):  
Tomasz Falborski ◽  
Robert Jankowski
Keyword(s):  
Base Isolation ◽  
Excitation Frequency ◽  
Hysteresis Loops ◽  
Shaking Table ◽  
Damping Properties ◽  
Structural Vibrations ◽  
Isolation System ◽  
Equivalent Damping ◽  
Flexible Polymer ◽  
Base Isolation System

The present paper summarizes the preliminary results of the experimental shaking table investigation conducted in order to verify the effectiveness of a new base isolation system consisting of Polymeric Bearings in reducing strong horizontal machine-induced vibrations. Polymeric Bearing considered in the present study is a prototype base isolation system, which was constructed with the use of a specially prepared flexible polymer with improved damping properties. Dynamic oscillatory tests, during which a concrete base slab supported by four Polymeric Bearings was subjected to horizonal sinusoidal excitations characterized by different frequencies and amplitudes, were conducted in order to determine the damping properties of Polymeric Bearings and their effectiveness in mitigating structural vibrations. Equivalent damping ratios for every excitation frequency considered were determined using the experimentally obtained hysteresis loops. Final conclusions are presented and the results discussed.

Bidirectional shaking table tests of a low‐cost friction sliding system with flat‐inclined surfaces

2020 ◽  
Vol 49 (8) ◽  
pp. 817-837
Author(s):  
Miguel B. Brito ◽  
Mitsuyoshi Akiyama ◽  
Yoshitaka Ichikawa ◽  
Hiroki Yamaguchi ◽  
Riki Honda ◽  
...  
Keyword(s):  
Low Cost ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Inclined Surfaces

Intelligent Identification and Locating System of Steel Coil Based on Laser Technology

2014 ◽  
Vol 496-500 ◽  
pp. 1308-1312
Author(s):  
Yu Chi Wang ◽  
Si Yue Zhou ◽  
Zheng Peng Yuan
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Least Square Method ◽  
Least Square ◽  
Circle Fitting ◽  
Three Dimensional Model ◽  
Laser Technology ◽  
Steel Coil ◽  
Main Emphasis ◽  
Locating System

In this paper, a solution based on laser technology is proposed for steel coil handling. The main emphasis is placed on the problem of steel coil identification and locating. In this paper, we first use laser data to construct three dimensional model of the worksite. And then we slice up the 3D model repeatedly to get the section images and make them to fusion. In order to wipe off the disturb of line, a line detection method based on probabilistic hough transform is proposed. Finally an improved least square method used in circle fitting is discussed.

Railroad track modeling based on the results of mobile laser scanning

2018 ◽  
pp. 408-413
Author(s):  
Elena Lenchenkova
Keyword(s):  
Mathematical Model ◽  
Laser Scanning ◽  
Dimensional Space ◽  
Practical Importance ◽  
Three Dimensional ◽  
Least Square Method ◽  
Least Square ◽  
Railroad Track ◽  
Railway Line ◽  
Type Data

Objective: To develop a mathematical model of the railroad track based on the initial progressive-type data (laser scanning) in railroad design. Methods: Regression analysis (least-square method), as well as coordinate methods of calculating point position in space were applied. Results: The mathematical model, which could describe the position of the railroad track in three-dimensional space by means of mathematical relations, was obtained. Applicability of approximating models was established. The models make it possible to provide smoothing of laser survey data. Regularization and globalization algorithms of initial data were developed. Practical importance: The introduced model is universal when describing the position of the track at all stages of life cycle of the railway line. It is reasonable to apply the presented model in design engineering in order to balance survey errors, maintain the track in coordinates, as well as to calculate design and profile parameters.

Research of Binocular Positioning Mathematical Model Based on the Least Square Method

2011 ◽  
Vol 50-51 ◽  
pp. 473-477 ◽  
Author(s):  
Chun Feng Liu ◽  
Xiao Li Meng ◽  
Huan Cheng Zhang
Keyword(s):  
Relative Position ◽  
Three Dimensional ◽  
Digital Camera ◽  
Least Square Method ◽  
Absolute Error ◽  
Least Square ◽  
Specific Data ◽  
Centroid Algorithm ◽  
Three Dimensional Coordinate ◽  
The Relationship

By giving a centroid algorithm to extract pixel coordinates of each circle in the center of a circle under the coordinates, through the coordinate transformation the image coordinates can be obtained. Based on the data obtained from above to verify the model, from the specific data of the relative error, absolute error and error propagation theory to discuss the algorithm accuracy and stability. Finally using the least square method, according to the mean square error criteria for the establishment of a minimum of three-dimensional coordinate system fixed relative position of two cameras, binocular positioning mathematical models and by discussing the nature of matrix and the relationship between the relative position of the camera to calibrate the binocular digital camera.

Nonlinear Modeling and Experimental Validation of Uni-Axial Servo-Hydraulic Shaking Table

2016 ◽  
Author(s):  
Paolo Righettini ◽  
Roberto Strada ◽  
Shirin Valilou ◽  
Ehsan Khademolama
Keyword(s):  
High Performance ◽  
Nonlinear Modeling ◽  
Least Square Method ◽  
Hydraulic Cylinder ◽  
Difficult Problem ◽  
Least Square ◽  
Shaking Table ◽  
Lugre Model ◽  
Friction Forces ◽  
Friction Models

An effective way for the testing of a large number of systems is using single and multi-axis shaking tables. Among the possible applications, the civil engineering field stands out for the testing of structures, or part of them, both on a reduced and on a full scale. However, design a high performance controller for a servo-hydraulic shaking table is a difficult problem due to its non-linarites and large friction forces. The goal of this paper is to develop and experimentally validate a robust numerical model that simulates the acceleration behavior of a uni-axial servo-hydraulic shaking table system with considering three friction models, the LuGre model, the modified LuGre model and the new modified LuGre model. First, a full system model of servo-hydraulic system is developed based on fluid mechanical expressions and then the friction force of hydraulic cylinder is modeled and validated on the real shaking table. Data of the experiment are gathered from input command valve, and the output acceleration and position of the table. All models are simulated by using MATLAB and SIMULINK computer program. The parameters of the system and the friction models are estimated by using least square method (LSM). Finally, the comparisons of simulated results with experimental ones show that the model of the system with considering third model of the friction can predict accurately the shaking table’s behaviors.

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