Papers by Keyword: Health Monitoring

Abstract: For large-scale structural damage in various forms, a single regional monitoring is difficult to finish. The paper introduces a design method of a large-scale structural health monitoring system based on wireless sensor networks. ZigBee wireless communication technology is used for the system. The ZigBee-based double wireless sensor network architecture is designed. The wireless sensor node, sink node, a gateway node of this system is designed by using the CC2530 chip as core of data processing and wireless transceiver. In the IAR development platform, the lower position machine software is designed by using C language and the LabVIEW is used to finish the remote display in the host computer. The results show that the monitoring system meets the design requirements, has the advantage of good on-line and real-time monitoring etc.

Abstract: The cable is the important force component of the cable-stayed bridges. The primary damage of cable is the corrosion which cause cable fracture. Local cable breaking lead to bridge force redistribution and have a certain impact to the mechanical characteristics of cable-stayed bridge, which affects the safety of bridge. The finite element model of cable-stayed bridge laboratory model is set up to simulate cable breaking and analyse the structure performance changes. At the same time carry out the corresponding cable breaking experiments. The conclusions through the theoretical and experimental analysis will provide a theoretical basis for the bridge health monitoring and bridge safety operation.

Abstract: Several techniques have been researched for detecting damage in plates. Each of these techniques offers their own unique advantages in detecting certain types of damage with various levels of analytical complexity. Lamb waves are guided waves that exist in thin walled structures. Because this type of wave can travel long distance with little attenuation, they have been studied intensively for structural health monitoring, especially in the past few decades. This paper presents an overview of using the Lamb waves in damage detection including the theory of lamb waves and the lamb-wave-based damage identification.

Abstract: This paper is focused on cement specimen testing by impact excitation non-destructive technique. The impulse excitation method was used for measuring of the natural frequencies and modes of longitudinal, transversal and torsional vibration of the specimens. The objective was to find dynamic properties of the specimens without a crack, with a crack and with a healed crack by cement paste and based on their comparison detect and localize the crack.

Abstract: After processed the signals obtained from monitoring system, one theory of condition evaluation was proposed on basis of a new evaluation parameter—index variation. One new condition grade division method was proposed from approximate statistic distribution of index variation, and as per the concept of confidence degree and confidence interval. Because the monitoring data and the standard of condition grade division were all interval numbers, interval extension evaluation theory was adopted to establish the model of condition evaluation. Set-Valued Statistics and gravity center based decision theory were introduced to divide weight into subjective weight and objective weight to make calculation. This evaluation method was found to be reasonable and had good project practicability.

Abstract: With advantages including capability of propagation over a significant distance and high sensitivity to abnormalities and inhomogeneity near the wave propagation path, Lamb waves can be energised to disseminate in a structure and any changes in material properties or structural geometry created by a discontinuity, boundary or structural damage can be identified by examining the scattered wave signals. This paper presents an overview of the Lamb-wave-based damage identification in laminated composite plates including the formulation of lamb waves in an isotropic plate.

Abstract: Complex structural pattern and behavior of Large-span steel structure result in famous research of health monitoring technology of this kind structure all over the world. Health monitoring to key parts of large-span steel structures during the construction and service process grasp the stress situation, which can ensure the safety of structures. In this paper, health monitoring project of Jinan Olympic Sports Center is introduced and the basis of test points’ layout is elaborated in detail. The result shows that the system designed is running stable, which means it has certain application value to other health monitoring to major engineering.

Abstract: Complex structural patterns and behaviors promote hot researches of health monitoring technology to large-span steel structures all over the world. Health monitoring to key parts of large-span steel structures during construction and service processes grasp the stress situation, which can ensure the safety of the structure. In this paper, self-developed health monitoring system which use vibrating wire sensor, had been developed to monitor Jinan Grand Theatre Concert Hall. The monitoring results show that there is no significant damage occurred in monitoring positions, which proves a reasonable design and a safe and stable state of the structure. Meanwhile, the self-developed health monitoring system has a high accuracy and good stability and can be widely applied.

Abstract: A new damage identification method for arch bridge structures under a moving load based on the difference of deflection is presented. The function of the deflection at the mid span of the arch with the changing positions of the moving load is derived using the Moore integral method. It can be concluded from the results that when the moving load is in the area without damage, this target indicates to be linear functions with the cosine of an angle (θ) between moving load and horizontal. Nevertheless, this target is multinomial with the change of cosθ in the damage area. In order to validate the proposed damage detection algorithm, a steel arch modal is simulated, which is proved to be practicable in projects. The results indicate that the location and degree of single damage can be identified accurately.

Abstract: There is little research on health monitoring technology of coastal ports at present. Based on the characteristics of high-piled wharf in coastal ports and staying in particular environment, the mechanical properties of coastal high-piled wharf is analyzed, and the health monitoring parameters are proposed. Finally, the health monitoring system of coastal high-piled wharf is constructed. And the appropriate structural health monitoring system is designed for standardized front segment of a high-piled wharf in the Tianjin port. The monitoring parameters are proposed, and the sensors and specification parameters are provided to reach the point. The data acquisition and transmission subsystem implementation technology and related indicators are given. This can provide a reference for the long-term health monitoring system construction in coastal high-piled wharf structure.