scholarly journals Study of Building Safety Monitoring by Using Cost-Effective MEMS Accelerometers for Rapid After-Earthquake Assessment with Missing Data

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7327
Author(s):  
Jian-Fu Lin ◽  
Xue-Yan Li ◽  
Junfang Wang ◽  
Li-Xin Wang ◽  
Xing-Xing Hu ◽  
...  
Keyword(s):  
Missing Data ◽  
Safety Assessment ◽  
Safety Monitoring ◽  
Cost Effective ◽  
Low Noise ◽  
Parameter Analysis ◽  
Structural Failure ◽  
Mems Accelerometers ◽  
Building Safety ◽  
Earthquake Assessment

Suffering from structural deterioration and natural disasters, the resilience of civil structures in the face of extreme loadings inevitably drops, which may lead to catastrophic structural failure and presents great threats to public safety. Earthquake-induced extreme loading is one of the major reasons behind the structural failure of buildings. However, many buildings in earthquake-prone areas of China lack safety monitoring, and prevalent structural health monitoring systems are generally very expensive and complicated for extensive applications. To facilitate cost-effective building-safety monitoring, this study investigates a method using cost-effective MEMS accelerometers for buildings’ rapid after-earthquake assessment. First, a parameter analysis of a cost-effective MEMS sensor is conducted to confirm its suitability for building-safety monitoring. Second, different from the existing investigations that tend to use a simplified building model or small-scaled frame structure excited by strong motions in laboratories, this study selects an in-service public building located in a typical earthquake-prone area after an analysis of earthquake risk in China. The building is instrumented with the selected cost-effective MEMS accelerometers, characterized by a low noise level and the capability to capture low-frequency small-amplitude dynamic responses. Furthermore, a rapid after-earthquake assessment scheme is proposed, which systematically includes fast missing data reconstruction, displacement response estimation based on an acceleration response integral, and safety assessment based on the maximum displacement and maximum inter-story drift ratio. Finally, the proposed method is successfully applied to a building-safety assessment by using earthquake-induced building responses suffering from missing data. This study is conducive to the extensive engineering application of MEMS-based cost-effective building monitoring and rapid after-earthquake assessment.

scholarly journals Research and development of comprehensive safety management system for super-tall buildings in Shanghai

2021 ◽  
Vol 236 ◽  
pp. 05008
Author(s):  
Jue Lu ◽  
Bo Zheng
Keyword(s):  
Data Analysis ◽  
Internet Of Things ◽  
Early Warning ◽  
Management System ◽  
Safety Assessment ◽  
Safety Management ◽  
Tall Buildings ◽  
Safety Monitoring ◽  
Safety Management System ◽  
Building Safety

In order to meet the requirements of comprehensive safety management of super-tall buildings, a set of integrated safety management system is developed, which can be popularized and demonstrated, including three subsystems of structure, enclosure and firefighting. Interfaces are reserved for water supply and drainage, facilities and equipment, strong and weak electricity and other building safety management subsystems, which can realize the functions of comprehensive safety assessment, safety early warning, Internet of things safety monitoring and data analysis of super-tall buildings. Through the demonstration application in Shanghai Center, it is eventually proved that the system is feasible and effective.

A validated robust and automatic procedure for vibration analysis of bridge structures using MEMS accelerometers

2020 ◽  
Vol 14 (3) ◽  
pp. 327-354
Author(s):  
Mohammad Omidalizarandi ◽  
Ralf Herrmann ◽  
Boris Kargoll ◽  
Steffen Marx ◽  
Jens-André Paffenholz ◽  
...  
Keyword(s):  
Vibration Analysis ◽  
Damping Ratio ◽  
Fem Analysis ◽  
Cost Effective ◽  
Analysis Procedure ◽  
Modal Parameters ◽  
Bridge Structure ◽  
Modal Damping ◽  
Mems Accelerometers ◽  
Better Than

AbstractToday, short- and long-term structural health monitoring (SHM) of bridge infrastructures and their safe, reliable and cost-effective maintenance has received considerable attention. From a surveying or civil engineer’s point of view, vibration-based SHM can be conducted by inspecting the changes in the global dynamic behaviour of a structure, such as natural frequencies (i. e. eigenfrequencies), mode shapes (i. e. eigenforms) and modal damping, which are known as modal parameters. This research work aims to propose a robust and automatic vibration analysis procedure that is so-called robust time domain modal parameter identification (RT-MPI) technique. It is novel in the sense of automatic and reliable identification of initial eigenfrequencies even closely spaced ones as well as robustly and accurately estimating the modal parameters of a bridge structure using low numbers of cost-effective micro-electro-mechanical systems (MEMS) accelerometers. To estimate amplitude, frequency, phase shift and damping ratio coefficients, an observation model consisting of: (1) a damped harmonic oscillation model, (2) an autoregressive model of coloured measurement noise and (3) a stochastic model in the form of the heavy-tailed family of scaled t-distributions is employed and jointly adjusted by means of a generalised expectation maximisation algorithm. Multiple MEMS as part of a geo-sensor network were mounted at different positions of a bridge structure which is precalculated by means of a finite element model (FEM) analysis. At the end, the estimated eigenfrequencies and eigenforms are compared and validated by the estimated parameters obtained from acceleration measurements of high-end accelerometers of type PCB ICP quartz, velocity measurements from a geophone and the FEM analysis. Additionally, the estimated eigenfrequencies and modal damping are compared with a well-known covariance driven stochastic subspace identification approach, which reveals the superiority of our proposed approach. We performed an experiment in two case studies with simulated data and real applications of a footbridge structure and a synthetic bridge. The results show that MEMS accelerometers are suitable for detecting all occurring eigenfrequencies depending on a sampling frequency specified. Moreover, the vibration analysis procedure demonstrates that amplitudes can be estimated in submillimetre range accuracy, frequencies with an accuracy better than 0.1 Hz and damping ratio coefficients with an accuracy better than 0.1 and 0.2 % for modal and system damping, respectively.

Using Parametric Simulation to Optimize Suspension Design

2003 ◽  
Author(s):  
G. Walter Rosenberger ◽  
Peter E. Klauser ◽  
George P. Binns ◽  
Gary P. Wolf
Keyword(s):  
Control Unit ◽  
Cost Effective ◽  
Parameter Analysis ◽  
Ride Quality ◽  
Worst Case ◽  
Suspension Parameters ◽  
History Of ◽  
Vehicle Response ◽  
Stiffness And Damping ◽  
Test Result

A project to design and implement suspension improvements to Amtrak’s F-40 Non-Powered Control Unit (NPCU) cars is described. The cars, built from former F-40 locomotives, had a history of poor ride quality. Rail Sciences Inc. (RSI) inspected one of the cab cars and measured its ride quality. Peter Klauser modeled the vehicle in NUCARS™ and validated the model against the test data. The vehicle response was primarily in pitch and bounce modes. To optimize the suspension, Klauser simulated vehicle response for a range of four suspension parameters: primary stiffness and damping, and secondary stiffness and damping. Nearly 2600 suspension combinations were considered. Simulation file setup and data analysis were performed automatically using parameter analysis software interacting with NUCARS™. The result was a five-dimensional response contour for each output variable, such as the engineer’s seat vertical and lateral accelerations, and car body acceleration. The most cost effective stiffness and damping parameters were selected from the response contour and translated into component specifications. RSI then provided Amtrak with new axle box springs and dampers, and re-tested the vehicle. The test result closely followed the predicted results from the simulation. Engineer’s seat vertical and cab lateral accelerations improved by 42% and 32% respectively for the worst-case conditions in the test territory.

scholarly journals IOT Based Coal Mine Safety Monitoring and Alerting System

2021 ◽  
pp. 404-410
Author(s):  
Prof. A. H. Ansari ◽  
Karishma Shaikh ◽  
Pooja Kadu ◽  
Nikam Rishikesh
Keyword(s):  
Mining Industry ◽  
Safety Monitoring ◽  
Cost Effective ◽  
Underground Mines ◽  
Mine Safety ◽  
Fundamental Aspect ◽  
Reliable Communication ◽  
Gas Leakage ◽  
Coal Mine Safety ◽  
Alerting System

Safety is the most vital part of any type of industry. In the mining industry safety and security is a fundamental aspect of all. To avoid any types of accidents mining industry follows some basic precautions. Still accidents take place in underground mines due to rise in temperature, increased water level, and methane gas leakage. Here we provide safety to worker. When worker in danger he can press panic switch inform security. To enhance safety in underground mines, a reliable communication system must be established between workers in underground mines and fixed ground mine system. The communication network must not be interrupted at any moment and at any condition. A cost effective zigbee based wireless mine supervising system with early-warning intelligence is proposed in this project. Worker status can be monitor over IOT.

Optimized Small Vertical Axis Wind Turbine (VAWT), Phase I

2021 ◽  
Author(s):  
Moshe Zilberman ◽  
Abdelaziz Abu Sbaih ◽  
Ibrahim Hadad
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Cost Effective ◽  
Clean Energy ◽  
Vertical Axis ◽  
Low Noise ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Different Types

Abstract Wind energy has become an important resource for the growing demand for clean energy. In 2020 wind energy provided more than 6% of the global electricity demand. It is expected to reach 7% at the end of 2021. The installation growth rate of small wind turbines, though, is relatively slow. The reasons we are interested in the small vertical axis wind turbines are their low noise, environmentally friendly, low installation cost, and capable of being rooftop-mounted. The main goal of the present study is an optimization process towards achieving the optimal cost-effective vertical wind turbine. Thirty wind turbine models were tested under the same conditions in an Azrieli 30 × 30 × 90 cm low-speed wind tunnel at 107,000 Reynolds number. The different types of models were obtained by parametric variations of five basic models, maintaining the same aspect ratio but varying the number of bucket phases, the orientation angles, and the gaps between the vanes. The best performing turbine model was made of one phase with two vanes of non-symmetric bipolynomial profiles that exhibited 0.2 power coefficient, relative to 0.16 and 0.13 that were obtained for symmetrical polynomial and the original Savonius type turbines, respectively. Free rotation, static forces and moments, and dynamic moments and power were measured for the sake of comparison and explanation for the variations in performances of different types of turbines. CFD calculations were used to understand the forces and moment behaviors of the optimized turbine.

Review of V/STOL Aircraft with Tilt-Propellers and Tilt-Rotors

1968 ◽  
Vol 72 (693) ◽  
pp. 817-830
Author(s):  
Henry V. Borst
Keyword(s):  
Second Generation ◽  
Cost Effective ◽  
Structural Failure ◽  
Secondary Importance ◽  
Flight Tests ◽  
Tilt Rotor ◽  
The Future ◽  
High Degree ◽  
Aircraft Configurations ◽  
Vtol Aircraft

Summary Tests of the first experimental VTOL aircraft using tiltable wings and propellers indicated that practical operational aircraft are possible and can operate with a high degree of effectiveness. The flight tests accomplished up to the present time with the second generation tilt-propeller and tilt-rotor aircraft are discussed and analysed. The XC-142 and the CL-84 tilt-wing aircraft have been performing well throughout their projected flight envelope and good pilot ratings have been obtained with each in hover, transition, and the normal cruise mode. The X-19 tandem wing tilt propeller was flown only up to 100 knots and was lost due to a structural failure in one nacelle. Although the operation of the aircraft had been satisfactory up to this point, this programme was terminated due to shortage of funds. A study of the various VTOL aircraft configurations operating at low radius of action indicates that the tilt wing/ tilt propeller type are the most cost-effective as long as speed is an important parameter in the operating mission. There are missions where speed is of secondary importance, and therefore, the helicopter will continue to be one of the most effective VTOL for these missions. Since the tilt-wing /tilt-rotor aircraft tend to be only slightly higher in cost than the helicopter and with development the complexity and maintainability will be reduced to acceptable levels, it is anticipated that further work will be done in the development of these vehicles, and successful and useful machines will be built in the future.

Toward highly scaled AlN/GaN-on-Silicon devices for millimeter wave applications

2013 ◽  
Vol 5 (3) ◽  
pp. 335-340 ◽  
Author(s):  
Farid Medjdoub ◽  
Yoann Tagro ◽  
Bertrand Grimbert ◽  
Damien Ducatteau ◽  
Nathalie Rolland
Keyword(s):  
Millimeter Wave ◽  
Noise Figure ◽  
Infrared Camera ◽  
Cost Effective ◽  
Low Noise ◽  
Silicon Devices ◽  
Heating Effects ◽  
Drain Bias ◽  
High Carrier ◽  
Gan On Si

In this work, the possibility of achieving GaN-on-Si devices for millimeter wave applications operating at high bias is demonstrated. It is shown that highly scaled AlN/GaN-on-Si double heterostructure enables us to significantly improve electron confinement under high electric field as compared to single heterostructure while delivering high carrier density (>2 × 1013 cm−2). Subsequently, trapping effects can be minimized resulting in the highest GaN-on-Si output power density up to 40 GHz and at a drain bias of 15 V together with a record fmax close to 200 GHz. At higher bias, infrared camera analysis clearly shows that these devices are mainly limited by self-heating effects. Furthermore, low noise figure has been assessed on this heterostructure, promising integration of cost effective low noise and high power millimeter wave amplifiers.

Safety Monitoring and Evaluation of Construction Projects Based on Multi-sensor Fusion

2020 ◽  
Vol 19 (6) ◽  
pp. 431-441
Author(s):  
Na Ni
Keyword(s):  
Missing Data ◽  
Monitoring System ◽  
Sensor Fusion ◽  
Construction Projects ◽  
Monitoring Network ◽  
Safety Monitoring ◽  
Monitoring And Evaluation ◽  
Construction Safety ◽  
Monitoring Data ◽  
Safety Monitoring System

For most construction projects, the complex engineering environment, the backward data collection technology, and the unreasonable monitoring network have resulted in many problems in monitoring data such as lots of noise and missing data items, therefore, it is of great significance to study the safety monitoring system of construction projects based on wireless sensor network (WSN). For this reason, this paper proposed a construction safety monitoring and evaluation (CSME) model based on multi-sensor fusion. First, the system structure and data flow model of the construction safety monitoring system were constructed; then, combining with a multi-sensor deep fusion system which was built on physical and information systems, this paper designed a spectrum sensing algorithm for sensor signals within the construction area. After that, tempo-spatial correlation analysis was conducted on the monitoring data, and a multi-sensor monitoring network joint sparse (MSMN-JS) model was constructed, which realized reconstruction of missing data items. At last, this paper used experimental results to prove the application value of the algorithm model to the safety monitoring and evaluation of construction projects.

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