Papers by Keyword: Health Monitoring

Abstract: EMI and the Lamb Wave technology are two kinds of mainstream active detection method in health monitoring , which have a long-term development. Health monitoring based on the combination of the EMI technology and Lamb wave, can be either a single method to conduct monitoring and analysis of specific structure ,or two methods together to conduct more comprehensive damage monitoring.

Abstract: The important problem is structure safety of large bridges. Building the structural health monitoring analysis management system can effectively assurance the safety and reliability of bridge. It was introduce the development process of structural health monitoring analysis management system of cable-stayed bridge of line 5on BEIJING metro. It was focus on development requirements, design ideas, the warning alarm settings of system. The research achievements of this paper can offer some reference value for similar projects

Abstract: A new method of reliability monitoring of electrical devices based on carbon fibres is presented. Due to the thermo-mechanical stress on electronic circuits a loss of fibre network integrity can take place and potential difference may appear between the edges of broken carbon fibres. This potential difference causes an intensive field-emission from surfaces of these broken carbon fibres and an acceleration of emitted electrons. Due to the acceleration of electrons a microwave emission is generated. A CFRP was used to simulate the behaviour of a carbon based electronic device. The sequence of microwave impulses was detected in a frequency bandwidth from 8 to 12 GHz. The rise time of detected microwave impulses is about of few nanoseconds. This time is in agreement with crack formation time in carbon fibre. The correlation between the change of electrical resistance of composites and microwave impulses by fibres fracture is observed. Thus, the breakdown of current that flows through carbon fibres induces detectable microwave emission. That means that defects in electrical circuits can be wireless detected online.

Abstract: Based on the Bluetooth technology, using wireless sensor network design the mountain of debris flow health monitoring system, analysied and fixed mountain monitoring elements, given the data acquisition and processing methods, the project is simple, low cost, high reliability . To solve monitoring, early warning, data analysis of the current landslides and debris flow disaster, which are very practical.

Abstract: Avionics software is safe-critical embedded system and its architecture is evolving from traditional federated architecture to Integrated Modular Avionics (IMA) to improve resource usability. As an architecture widely employed in the avionics industry, supports partitioning concepts. To insure the development of the avionics software constructed on IMA operating system with high reliability and efficiency Health Monitoring (HM) has been shown to be a key step in reducing the life cycle costs for structural maintenance and inspection. In this paper , we propose a model-driven test methodology using Architecture Analysis &Design Language (AADL). It proposes modeling patterns of IMA errors to support the test case generating mechanisms of the HM module, proposing 3 kinds of test cases that can be injected in the HM to stimulate these kinds of errors, and we present the preliminary results that can meet the satisfactory from a ongoing project based on IMA system.

Abstract: In this study, the marginal spectrum based on instantaneous parameter is applied to the active Lamb wave-based health monitoring of plate structure to investigate the marginal spectrum variation of the signals after being added with damage scattering signal. First,the active Lamb wave monitoring technology is employed to obtain the Lamb wave signals of the plate before and after damage. Then the marginal spectra of the signals before and after damage are obtained using the HHT technology and compared with the spectrum of the signals. The results show that the marginal spectrum can better describe the variation of the signals before and after damage.

Abstract: In this paper we present a system for aircraft structural health monitoring based on artificial immune systems with negative selection. Inspired by a biological process, the principle of discrimination proper/non-proper, identifies and characterizes the signs of structural failure. The main application of this method is to assist in the inspection of aircraft structures, to detect and characterize flaws and decision making in order to avoid disasters. We proposed a model of an aluminum beam to perform the tests of the method. The results obtained by this method are excellent, showing robustness and accuracy.

Abstract: This paper describes an experimental study on the use of Lamb wave propagation for the integrity assessment of the composite patch system. Composite repairs are performed to the cracked specimen. Two piezoelectric sensors were installed around the composite patch. The piezoelectric sensor response was recorded periodically during the fatigue test. Three types of the damage index based upon the piezoelectric sensor response were selected and calculated to describe the health of the composite patch system. The results show that the damage index based upon the waveform relativity has the best correlations with the expanding process of the damage of the composite patch system.

Abstract: Crack detection and monitoring has become one of a focus center for the health monitoring of engineering structures under the influence of mechanical deformation.This paper discusses the detecting, tracking and monitoring mechanisms for the crack, by initiating a sensing system by using a standard notched specimen. Crack features such as magnitude of crack travel versus crack opening are displacement indicators that can vary due to the applied load on the normal line to the direction of the crack travel. More ever, the rate of the crack opening is considered to be proportional to the rate of the crack travel.Lines of three optical fibers of 125 nm are embedded and fixed at two ends and pass across the direction of the crack travel at an approximation of 2mm apart. The light of 2V from the source is passed through the optical fiber, across the crack tip. The crack opening forces the optical fiber to extend under tension, and hence the interruption of its diameter. This causes the decrease in the light intensity traveling through the fiber till the total failure of the fiber, to declare presence of crack. The embedded fiber optics on the specimen links the instrumentation optical system which permits the light beam throughput. Finally the converted light beam into voltage domain allowed us to closely analyze the crack tendency, and eventually be able to establish a model and sensor equation which governs the trend of the crack growth.

Abstract: For better monitoring of the person's health status, this paper designed and realized a remote health monitoring system. The paper describes design principle of each part of the system. The system is based on wireless body area network. It collected health data using C8051F020 MCU. It transmitted data by Bluetooth and IP networks. The dynamic monitoring results displayed on PC, mobile terminals or remote testing center by GIS map. After testing, the system can accurately capture, transmit and display pulse and body temperature. The test results show that the system is stable, easy to operate.