• Smart Structures and Systems
• /
• v.12 no.3_4
• /
• pp.271-290
• /
• 2013

The acceleration information is significant for the structural health monitoring, which is the basic measurement to identify structural dynamic characteristics and structural vibration. The efficiency of the accelerometer is subsequently important for the structural health monitoring. In this paper, the distance measure matrix and the support level matrix are constructed firstly and the synthesized support level and the fusion method are given subsequently. Furthermore, the synthesized support level can be served as the determination for diagnosis on accelerometers, while the consensus data fusion method can be used to recover the acceleration information in frequency domain. The acceleration acquisition measurements from the accelerometers located on the real structure National Aquatics Center are used to be the basic simulation data here. By calculating two groups of accelerometers, the validation and stability of diagnosis and recovering on acceleration based on the data fusion are proofed in the paper.

• Journal of the Korean Society of Safety
• /
• v.28 no.1
• /
• pp.74-80
• /
• 2013

This study describes structural reliability analysis of actively-controlled structure for which random vibration analysis is incorporated into the first-order reliability method (FORM) framework. The existing approaches perform the reliability analysis based on the RMS response, whereas the proposed study uses the peak response for the reliability analysis. Therefore, the proposed approach provides us a meaningful performance measure of the active control system, i.e., realistic failure probability. In addition, it can deal with the uncertainties in the system parameters as well as the excitations in single-loop reliability analysis, whereas the conventional random vibration analysis requires double-loop reliability analysis; one is for the system parameters and the other is for stochastic excitations. The effectiveness of the proposed approach is demonstrated through a numerical example where the proposed approach shows fast and accurate reliability (or inversely failure probability) assessment results of the dynamical active control system against random seismic excitations in the presence of parametric uncertainties of the dynamical structural system.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2058-2062
• /
• 2005

This article describes the useful way to measure the torque and RPM of the geared motor. For this, we have made the planetary geared reduction motor including the torque sensor unit which consists of hall effects sensor and permanent magnet. Our monitoring system displays the sensing values (torque, rpm) and the calculated value (power) and it also has the network capability using the Bluetooth protocol. We will show that our solution is much more inexpensive and simple method to measure torque and rpm than before.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.607-611
• /
• 2006

There are several methods to obtain structural vibration for analysis of vibro-acoustic noise. First of all, vibration data can be obtained through the structural analysis using finite element method. Although this method has no need to experiment, the analysis result is unreliable when the structure and the vibration source is complex to model exactly. The second method is to measure vibration using a number of sensors. The analyzed vibro-acoustic noise with directly measured data is setting morereliable when the number of data acquisition points is getting larger. However, it requires large amount of time and effort to measure all vibration data on every node especially when the size of vibrating structure is large. The Modal Expansion Method(MEM), which uses mode information and measurement data, has been introduced to compensate their limits. With a relatively small number of measurement data, the reliable structural vibration for vibro-acoustic noise can be obtained using this semi-analysis method. Although MEM gives reliable result, it is restricted by the number of modes and measurement points. In this paper, structural analysis, direct vibration measurement method and MEM are compared using the simple aluminum box model. Furthermore, the washing machine case is also provided as a comparative example. The Laser Doppler Vibrometer(LDV) was used instead of contact type accelerometer to get vibration data.

• Wind and Structures
• /
• v.20 no.2
• /
• pp.315-326
• /
• 2015

To overcome the drawbacks of the traditional contact-type sensor for structural displacement measurement, the vision-based technology with the aid of the digital image processing algorithm has received increasing concerns from the community of structural health monitoring (SHM). The advanced vision-based system has been widely used to measure the structural displacement of civil engineering structures due to its overwhelming merits of non-contact, long-distance, and high-resolution. However, seldom currently-available vision-based systems are capable of realizing the synchronous structural displacement measurement for multiple points on the investigated structure. In this paper, the method for vision-based multi-point structural displacement measurement is presented. A series of moving loading experiments on a scale arch bridge model are carried out to validate the accuracy and reliability of the vision-based system for multi-point structural displacement measurement. The structural displacements of five points on the bridge deck are measured by the vision-based system and compared with those obtained by the linear variable differential transformer (LVDT). The comparative study demonstrates that the vision-based system is deemed to be an effective and reliable means for multi-point structural displacement measurement.

• East Asian mathematical journal
• /
• v.36 no.1
• /
• pp.55-60
• /
• 2020

We study a probabilistic approach for valuing an exchange option with default risk. The structural model of Klein [6] is used for modeling default risk. Under the structural model, we derive the closed-form pricing formula of the exchange option with default risk. Specifically, we provide the pricing formula of the option with the bivariate normal cumulative function via a change of measure technique and a multidimensional Girsanov's theorem.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1991.04a
• /
• pp.29-33
• /
• 1991

This paper reports the application study of the ground reinforement under a buried pipeline subjected to differential settlement via a finite element modelling. The Soil-reinforrement interaction helps to mimimize the differential settlement between the adjoining pipe segments. The settlement pattern and deformation slope of a pipeline have been evaluated for a boundary condition at the joint between a rigid structure and apipeline. The analysis results are compared for both non-reinforied and reinforced cases to measure the effectiveness of the soil reinforcement for restraining the settlement of the pipeline.

• Communications for Statistical Applications and Methods
• /
• v.14 no.3
• /
• pp.577-582
• /
• 2007

A continuum structure function (CSF) is a non-decreasing mapping from the unit hypercube to the unit interval. A B-type CSF, defined in the text, is a CSF whose behaviour is modeled by its underlying binary structures. As the measure of importance of a system component for a B-type CSF, the structural and reliability importance of a component at a system level ${\alpha}$(0 < ${\alpha}$ < 1) are defined and their properties are deduced.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1994.04a
• /
• pp.171-180
• /
• 1994

Full scale structural test of 765kv electric transmission tower was performed to measure the stresses and displacement of towers under the design loadings, and the results were compared with analytical results based on three dimensional frame analysis. Also, the actual ultimate strength of the tower was measured through destructive test. Especially, to predict the behavior and failure of the connection of tubular member, finite element analysis was performed and compression test for the segments of tubular member were carried out. Valuable information for the overall and local behavior of the tower was obtained and reliability of current analytical method was confirmed.

• Journal of the Society of Naval Architects of Korea
• /
• v.38 no.2
• /
• pp.44-52
• /
• 2001

A modeling program was developed in Part I which represents the 3-D geometry, produces bill of material, automatically draws drawings and produces input data for structural analysis of Very High-rise Steel Artificial Reefs(VEHSAR). Model tests were carried out to measure drag forces acted on VEHSAR in the Ocean Engineering Wide Tank, the University of Ulsan and structural analyses were made to simulate structural behaviors of VEHSAR. The integrated package system is suggested to design VEHSAR with different geometries.