Safety State Evaluation Research Articles

Multisource information fusion model for deformation safety monitoring of earth and rock dams based on deep graph feature fusion

Constructing a long-term deformation monitoring model for earth–rock dams that integrates multisource monitoring information is highly important for enhancing the safety state evaluation and monitoring effectiveness of such dams. In this paper, we propose a new health monitoring model named the deformation–seepage–water level multimeasurement point health monitoring (DSW-MPHM) model for earth–rock dams based on deep graph feature fusion. This model fuses coupled seepage, deformation, and water level features from different monitoring sites of the dam body, base, and shoulder. To achieve this goal, we first establish a new module to fuse spatial and temporal features using graph convolutional networks and long short-term memory. Seepage features and water level features are then extracted using graph attention mechanisms. Subsequently, we employ the feature fusion technique, which incorporates principal component analysis and gated fusers, to construct the DSW-MPHM model, which effectively fuses information from multiple sources. This novel approach successfully addresses the issues of information redundancy and the limited reliability of monitoring models. To verify the validity of the model, it is applied to an endoscopic deformation monitoring program of a panel rockfill dam with a height of 185.5 m. The results demonstrate the superior stability and effectiveness of the proposed method compared to those of 10 baseline prediction models. Additionally, the characterization of the seepage and water level features extracted from the model is verified for its reasonableness. Thus, our proposed model is well suited for practical engineering applications.

Physical data-driven modeling of deformation mechanism constraints on earth-rock dams based on deep feature knowledge distillation and finite element method

Constructing an interpretable model for the long-term deformation Structural Health Monitoring (SHM) of earth-rock dams is of great significance for improving the safety state evaluation and monitoring effect. In this paper, a physics-data-driven model for the deformation SHM of earth-rock dams is proposed based on deep mechanism knowledge distillation. Firstly, the deterministic model is established based on the Finite Element Model (FEM) and outputs the hydraulic load component curve and aging component curve. Then a regression prediction model (HTSGAN) between influencing factors and deformation measurements at multiple measurement points is established based on the Graph Convolutional Network (GCN) and attention mechanism. Finally, the Teacher-Hydraulic-Time-Seepage Graph Attention Networks (T-HTSGAN) model is established based on the feature-based multi-teacher knowledge distillation using the knowledge of hydraulic loading physics and soil-rock creep physics of the FEM for mechanism constraints. The model effectively solves the problems of poor model interpretability and lack of physics knowledge constraints in previous earth-rock dam SHM models. The research results are applied to a project of a 185.5-meter-high concrete-faced rockfill dam, and the predictive performance of the model is more effective and stable through the comparison of six baseline models. The comparative analysis of the component curves proves the effectiveness of the proposed knowledge distillation method for mechanism constraints and improves the interpretability of the neural network model. Therefore, the model is more suitable for engineering applications.

Research on Safety State Evaluation of Cable-Stayed Bridge Structures across the Sea

In response to the lack of relevant research on the health monitoring system and assessment of the structural safety status of a cable-stayed bridge across the sea, the real-time monitoring data was determined by the health monitoring system installed on the bridge structure. Strain and displacement data for the bridge structure were analyzed and processed. Based on operational research principles, a safety condition assessment of the Channel 1 Bridge was conducted using the Analytic Hierarchy Process (AHP). First, the reserve strength method is applied to determine the weight proportion of monitoring indicators such as strain and displacement. Secondly, the weight proportion of each monitoring indicator at different cross-sectional positions is determined. Then, the hierarchical division of the cable-stayed bridge structure is performed from the lowest layer, and the rating level of the Channel 1 Bridge structure is obtained using the variable weight synthesis method. This provides a basis for management decisions in the bridge maintenance department and serves as an example for future safety assessments of medium-span cable-stayed bridges over the sea.

A resilience assessment framework for existing underground structures under adjacent construction disturbance

Scientifically and reasonably evaluating the safety of existing underground structures under adjacent construction disturbances is of great importance. In this paper, a resilience assessment framework including five steps is proposed to investigate the composite performance and comprehensive resilience of the evaluated structure-stratum system under adjacent construction disturbance. A Performance-Time-Cost three-dimensional space is constructed to interpret the evolution laws of composite performance and recovery costs over time. Using the cross-matrix method from the concept of resilience, the resilience indicator system is constructed. Moreover, the composite performance with multiple indicators of the evaluated system is continuously evaluated using the set pair analysis theory and the combined weights in terms of game theory. Furthermore, the formulas for comprehensive resilience assessment are derived from the perspectives of maximum and cumulative damage of composite performance. Finally, the correctness and rationality of the resilience assessment are verified by engineering applications. The resilience framework proposed in this paper provides theoretical and technical support for the safety state evaluation and control technology of existing underground structures under adjacent construction disturbances.

Safety state evaluation method of the highway tunnel structure

This study proposes an evaluation method for the structural safety of expressway tunnels utilizing possibility and prospect theories to address the influence of multiple indicators on the structural safety of expressway tunnels and the imprecision of human-bounded rationality in assessing results. It constructs the probability distribution of safety level by determining the safety level of the highway tunnel structure. The reference distribution function of each monitoring index is then derived using the expected value of experts. Based on the possibility theory, the possibility distribution of the monitoring results of indicators is obtained, and the mapping relationship between the monitoring indicators and the possibility distribution function of safety status grade is developed. Finally, the prospect theory evaluates the highway tunnel structure's safety status. This method is applied to assess the structural safety of a highway tunnel, which verifies its effectiveness and practicability, and provides a new method for evaluating the structural safety of a highway tunnel.

Study on the safety speed of vehicle turning with considering the driving safety evaluation

Safety speeds estimation, as an indispensable link in the development of the aided or automatic drive, receives wide attention recently. Due to uncertain disturbances of vehicle driving, it is a challenging task to estimate the safety speed credibly. This work proposes a modified estimation approach to predict the turning safety speed by combining the static drive safety evaluation with the dynamic vehicle speed calculation. First, the driving safety state is evaluated considering the coupling of driver-vehicle-road-environment, where a comprehensive evaluation is obtained by combing the analytic hierarchy process and entropy weight analysis method. Then, a turning critical speed is calculated based on the vehicle driving dynamics considering both sideslip and rollover. The estimation of turning safety speed is achieved by modifying the critical speed with a safety correction factor obtained from the driving safety state evaluation. Finally, cases discussion on driving safety states evaluation, as well as the critical speed verification and safety speed analysis, are carried out. The results verify the validity of the driving safety state evaluation and critical speed calculation. The safety speeds have a reasonable safety margin according to the driving safety state evaluation. The maximum differences between the safety speeds and critical speeds are about 26.45% for buses and 26.39% for cars under low adhesion conditions, showing sufficient reliability for safety speed estimation.

Research on Early Warning of Hoist Failure based on Big Data and Parallel Simulation

Aiming at the problems of easy fault diagnosis and difficult early warning of mine hoist, a parallel system architecture of hoist fault early warning based on big data is proposed, the structure of each subsystem of hoist is analyzed, and a parallel simulation system of hoist fault early warning is established; secondly, the Hadoop ecosystem of hoist is established on the virtual machine, and the massive data is mined by using clustering algorithm and association rule algorithm, so as to speed up the calculation speed and improve the reliability of early warning; finally, the safety state evaluation rules of hoist are proposed, and the system decision is made according to the fault early warning results. The experimental results show that it can achieve the purpose of fault prediction.

Safety-state evaluation model based on structural entropy weight–matter element extension method for ancient timber architecture

This article investigates various factors that may influence the safety state of ancient timber architecture, to improve the accuracy of safety-state evaluation results for ancient timber architecture. During the process, a safety-state evaluation system for ancient timber architecture is developed. This safety-state evaluation system includes five parts: foundation, plinth, timber frame, enclosing wall, and roof. Based on the system, a safety-assessment model for ancient timber architecture based on structural entropy weight–matter element extension model is also introduced. In this model, the structural entropy weight method is applied to calculating the weight of each index and takes the influence of subjective and objective weights into consideration comprehensively. This model has the following three detailed steps. First, correlation function and correlation degree of extension set are used to quantify the relationship between the evaluation indexes of the components, joints, and evaluation interval of each safety state. Second, the safety states of units are determined according to the distribution of safety state of the components. Third, the safety degree of the entire structure is determined via the minimum safety state of units. This study also uses the Niaoqiangsanchu in Forbidden City as a study case and found that the evaluation results are consistent with the results of the practical damage survey and the actual situation of the architecture. The model thus minimizes the uncertainty of qualitative and quantitative factors in the process of evaluating the safety degree of ancient timber architecture, to finally obtain the objective evaluation results.

Engineering application of a safety-state evaluation model for hidden frame-supported glass curtain walls based on remote vibration

Laser doppler vibrometer (LDV), which has measurement advantages such as being remote and non-contact, accurate, and having rapid dynamic response, is a useful assessment tool for the safety-state evaluation of hidden frame-supported glass curtain walls (HFSGCW). The engineering application influence factors of a LDV safety-state evaluation model for HFSGCW were analyzed and the vibration frequency for practical cases was tested in this paper. Results show that the first order peak frequency from a frequency spectrum obtained by LDV can be selected as the safety-state evaluation index for HFSGCW caused by structural sealant failure. A rubber hammer is an effective way to excite glass panels to obtain an accurate vibration frequency spectrum. The middle of glass panels is advisable to be selected as the measurement point to obtain an accurate dynamic frequency. The frequency spectrum of a glass panel edge point can be used to determine structural sealant failure position. Binoculars are suggested to be added in order to improve working efficiency of LDV for measurement distance greater than 10 m. Pasting reflective film is an effective way to increase LDV test signal accuracy. The glass panel safety-state of a commercial center building in Guangdong (China) is accurately evaluated by LDV, and those test results provide guidance for real-time monitoring and repair of HFSGCW.

Safety State Evaluation Method Based on Attribute Recognition Model for Ancient Timber Buildings

To improve accuracy of safety state evaluation results for ancient timber buildings and to know the real state of the building, a safety grade evaluation model of ancient timber buildings is established based on attribute mathematic theory. From the perspective of macro, micro, qualitative, and quantitative, 22 factors may adversely affect the safety state of ancient timber building are considered in this model. First, evaluation system is established, and evaluation indexes are selected based on former study, seismic damage data, and Chinese current code about ancient timber buildings. In the evaluation system, whole building is divided into four parts, which are wood frame, enclosing wall, foundation, and plinth. Different parts contain different components. Every component has its own evaluation indexes. Second, based on the AHP and entropy method, the comprehensive empowering method is used to determine the weights of the indexes. Third, the attribute recognition model is established to identify the safety grade of components or units. Fourth, based on the evaluation results of components, safety grade of units is identified. Then, safety degree of the entire building is determined by the minimum safety grade of units. At last, the model is applied to the “Liben hall” in village Siping, Zhejiang province, China, and the assessment results are consistent with the results of damage identification.

The evaluation of safety state on road transport of dangerous goods

The article presents the threats problems on dangerous goods in road transport and alarming statistics data of mentioned issues. The proposition of the project of safety system for dangerous goods in road transport was stressed. It will permit to improve safety of people and environment and determine methods to limit incidental damages, carriers, receiver and emergency determine methods of cooperation at breakdown place.

Cooling phenomena in blast furnace hearth

Cooling water provides the best protection for refractory in the blast furnace hearth. Stable and suitable water quality and abundant cooling water are the basis for long service life of the hearth. Some phenomena about cooling system in the commercial blast furnaces were described, and reasonable explanations of these phenomena were analyzed. The results show that increasing the amount of cooling water and reducing the inlet temperature of cooling water can increase the cooling effect significantly in the case of water scaling. Heat flux in the blast furnace hearth is the average heat flux of cooling stave, and the erosion of carbon brick is uneven. There is no direct connection between the actual erosion condition and the heat flux in the hearth. The change trend of thermocouple temperature and heat flux in the hearth can reflect whether the gaps exist among the bricks or not, providing an effective guidance for industrial production and the evaluation of safety state in the hearth. And, the film boiling will not occur in the normal cooling system in the blast furnace hearth.

Modal analysis related safety-state evaluation of hidden frame supported glass curtain wall

The glass panel dropping off of hidden frame supported glass curtain wall (HFSGCW) caused by structural sealant failure has become a severe safety problem up to now. In order to obtain a rapid and effective safety-state evaluation method for HFSGCW glass panel, the modal analysis of a simulation HFSGCW glass panel at different working conditions was done using data acquisition and signal processing sensor system. The safety-state evaluation model for HFSGCW glass panel was proposed on the basis of modal parameters. The results showed that the modal frequency of HFSGCW glass panel decreases and the damping ratio increases with the failure increase of structural sealant. The first order modal parameters are more suitable for glass safety-state evaluation. The first peak frequency and damping ratio obtained from the self-power frequency spectrum of the middle location of HFSGCW glass panel can be used instead of modal analysis results to evaluate the safety-state of glass panel. The sealant failure can be identified from the amplitude change of the first peak frequency when the structural sealant is chosen as the excitation point. The safety-state HFSGCW glass panel is divided into three levels providing important guiding significance for HFSGCW safety-state evaluation.

Rapid evaluation of safety-state in hidden-frame supported glass curtain walls using remote vibration measurement

The vibration performance of a simulation for a hidden-frame supported glass curtain wall (HFSGCW) was tested using a Laser Doppler Vibrometer (LDV) in this paper. The effect of silicon structural sealant on the first order inherent frequency of HFSGCW and the spectral characteristics per LDV on different points were studied. Meanwhile, the test results of LDV were verified using traditional sensors (DASP modal analysis system) in order to evaluate the feasibility of LDV used for safety state evaluation of HFSGCW. Results show that the first order inherent frequency obtained by LDV matches well with DASP modal analysis results. The first order inherent frequency decreases with an increase of sealant failure，and the first order frequency amplitude scale of structural sealant upper point increases significantly after the structural silicon sealant is destroyed. The safety state of HFSGCW is divided into three levels. Meanwhile, a safety state rapid evaluation model and key detection technologies of HFSGCW based on LDV is proposed.

A novel CPS-based vehicle safety state evaluation scheme

In order to obtain consecutive vehicle safety states (CVSSs) for a vehicle safety warning system (VSWS), a novel CVSS calculation scheme, tightly coupling the vehicle's cyber system and its physical dynamics (the cyber–physical system (CPS)), has been developed. The proposed scheme objectively divides the dynamic vehicle distance changes into a cyber process and a physical process, defines the notions of minimum safety distance and safety constants and then improves the dynamic vehicle safety distance calculation scheme using the vehicle velocity, acceleration, the velocity difference and other parameters in the consecutive vehicle distance for scenarios of staying in the same lane and changing to a different lane. The simulation results show that the proposed scheme is practical and effective, and can offer advice for VSWS designs.

Early Warning of Power Plant Equipment Based on Massive Real-Time Data Mining Technology

This paper mainly discusses the application of the mass real-time data mining technology in equipment safety state evaluation in the power plant and the realization of the equipment comprehensive quantitative assessment and early warning of potential failure by mining analysis and modeling massive amounts of real-time data the power equipment. In addition to the foundational technology introduced in this paper, the technology is also verified by the application case in the power supply side remote diagnosis center of Guangdong electric institute.

Risk Evaluation in Marine Traffic Systems Based on Fuzzy Catastrophe Theory

The main purpose of MArine Traffic Safety System (MATSS) study, based on catastrophe theory, is to ensure the safety of marine traffic and reveal the essence of traffic risks, and so as to create an effective risk prediction and control mechanism. In this paper, cusp catastrophe was modeled and evolutionary path of MATSS was described. Hence, Fuzzy Catastrophe Theory was concluded. This theory combines Fuzzy Math with Catastrophe Theory and is derived from analysis of uncertainties of marine traffic, including dynamics, irreversibility and mutability. The adverse impacts of system potential function and uncertainties of outside controlling factors were minimized via developing such a theory. The marine traffic risk model was created taking perspectives of various observers into consideration accordingly. As a result, Fuzzy Catastrophe Evaluation Method was presented, which is beneficial to the system safety state evaluation and decision. In the end of the paper, the objectivity and rationality of the method was validated by MATLAB, which has broad application in marine risk prediction and control.

Study of Tower Surface Crack Size Effect Based on Weibull Theory

This paper presents the evaluation of safety state of for tower surface with Weibull and Fractal theory which simulate stress situation of the different scales on the cable-stayed tower surface with PFC. The combination of the Weibull theory and the Fractal theory evaluated the crack condition on the surface of the cable-stayed tower. Calculation results of three specimens showed that the number of the cracks increased when the load step and surface size increased. At the same time, the largest size of specimen had the biggest fractal dimension. The discrete element numerical simulation shows that Weibull modulus was successfully used to evaluate the crack extension of the cable bent tower.

Remote Monitoring and Assessment Systems Design for Long-Span Continuous Rigid Frame Bridges

On the basis of analyzing the necessary, such as the bridge monitoring data management, safety state evaluation, evaluation opinions and etc , this paper designs a remote monitoring and assessment system (BRMAS)with the parametric, intelligent and modular design thought, and applicates object-oriented software Microsoft VC++ to developt BRMAS system, which gives a system structure, function module and evaluation model. Through applying the design scheme and developed software into a highway bridge management, applications indicated that BRMAS system is very maneuverable, and realize the modern information management of bridges.