Merging advanced sensing techniques and simulation tools for future structural health monitoring technologies

Merging advanced sensing techniques and simulation tools for future structural health monitoring technologies Project DREAM-ON aims to design smart autonomous mechanics structures, able to perform online control of their health and take anticipated actions during service for increased reliability and performance. Its innovative concept is a synergistic, real- time, and robust dialogue between advanced sensing techniques and powerful simulation tools to make all knowledge on the physical system available and perform early damage detection, precise diagnosis, and safe decision making.

Early Weak Fault Diagnosis of Rolling Bearings Based on Fiber Bragg Grating Sensing Monitoring

Aiming at the problems of weak dynamic response and difficulty in diagnosis of early damage of rolling bearings, a diagnosis method for early damage of rolling bearings is proposed. Taking radial rolling bearings as the main research object, the load symmetric structure of deep groove ball bearings is analyzed. Based on the mechanical second-order system theory, the sensor monitoring structure is constructed. The generalized resonance principle is used to identify weak signals, and the fiber Bragg grating is used for signal sensing. The signal is obtained through the fiber Bragg grating high-speed demodulator. When a continuous periodic generalized resonance wave appears in the amplitude–frequency analysis of the signal, and there is a high-frequency resonance frequency, it can be proved that the bearing is faulty. The diagnosis method can effectively avoid the interference of low-frequency signals, the frequency spectrum is pure and there is no electromagnetic interference. It fully shows that the fiber Bragg grating sensor is suitable for the monitoring and diagnosis of the early weak fault of the bearing.

Cobalt Molybdate Incorporated Thermoset Composites: Preparation and Characterization

Piezo-chromic oxides are able to mark pressure or strain by a drastic color change. In this paper, CoMoO4 molybdate compound and related thermoset composites were prepared in lab. The distribution of CoMoO4 oxide in the thermoset matrix was first investigated via SEM. Moreover, the effects on the thermal and mechanical properties with the addition of CoMoO4 oxide were further analyzed. The piezo-chromic characteristic for CoMoO4 incorporated thermoset composites were verified with compression test. The color change can be clear visualized at a strain level close to the yield point of the composite blends. This study has the potential to open new directions to piezo-chromic polymeric materials as early damage detector.

Analysis of Circular Elevated Service Reservoir Using STAAD Pro by Considering the Effect of Continuity

In most regions of the country, early damage of elevated water tanks during their service life is becoming an increasing concern. The majority of damage occurs in tanks due to a lack of knowledge in design and ignoring continuity effect. Elevated water tank are used for storage of water at certain height and supplying water for essential usage. Hence damage of such structure endanger supply of drinking water and severe economical losses. The main purpose of this research is to determine the importance of continuity analysis in practical application and use of staadpro software to analyse an elevated circular water tank. The bottom joint of water tank is examined using continuity effect. This is the common joint where base slab, wall, bottom rings beam, gallery, column and base beam join. water tank is subjected to self-weight and hydrostatic Pressure due to water. Continuity effect increase stress, Hoop tension, BM hence its necessary to consider its effect while designing the tank. The results obtained from staadpro software is nearly same with manual result. This indicated that staadpro is suitable for design and analysis of water tanks. Three model having capacity of 55 m3, 125 m3 and 221 m3 situated in yavatmal, buldana and ramtek district is taken for analysis. Seismic analysis and wind analysis is also carried out on this model for safety purpose.

ASPHALT CHARACTERISTICS OF CONCRETE ASPHALT MIXED TO REDUCE EARLY DAMAGE IN FLEXIBLE PAVEMENT

Pavement roads in Indonesia often suffer premature damage. Efforts to overcome road damage need to be done by using pavement materials suitable for the climate in Indonesia. This research discusses the comparison of Pertamina asphalt 60/70 and Shell asphalt 60/70 in the concrete asphalt mixture. The variation of the bitumen content used in this study was 4%, 4.5%, 5%, 5.5%. From the test results, it can be concluded that Shell asphalt 60/70 penetration is relatively better in terms of the considerable penetration value, softening point, stability value, flow, and Marshall Quotient, which are higher than Pertamina's 60/70 penetration asphalt.

A novel data-driven method for structural health monitoring under ambient vibration and high-dimensional features by robust multidimensional scaling

Dealing with the problem of large volumes of high-dimensional features and detecting damage under ambient vibration are critical to structural health monitoring. To address these challenges, this article proposes a novel data-driven method for early damage detection of civil engineering structures by robust multidimensional scaling. The proposed method consists of some simple but effective computational parts including a segmentation process, a pairwise distance calculation, an iterative algorithm regarding robust multidimensional scaling, a matrix vectorization procedure, and a Euclidean norm computation. AutoRegressive Moving Average models are fitted to vibration time-domain responses caused by ambient excitations to extract the model residuals as high-dimensional features. In order to increase the reliability of damage detection and avoid any false alarm, the extreme value theory is considered to determine a reliable threshold limit. However, the selection of an appropriate extreme value distribution is crucial and troublesome. To cope with this limitation, this article introduces the generalized extreme value distribution and its shape parameter for choosing the best extreme value model among Gumbel, Fréchet, and Weibull distributions. The main contributions of this article include developing a novel data-driven strategy for early damage detection and addressing the limitation of using high-dimensional features. Experimental data sets of two well-known civil structures are utilized to validate the proposed method along with some comparative studies. Results demonstrate that the proposed data-driven method in conjunction with the extreme value theory is highly able to detect damage under ambient vibration and high-dimensional features.

Near-Infrared Reflectance Imaging to Detect an Incipient Retinal Arterial Macroaneurysm

Retinal arterial macroaneurysms (RAM) are characterized by a saccular or fusiform dilation of the retinal artery wall. An 84-year-old Caucasian woman with a medical history of poorly controlled hypertension was diagnosed with RAM in the left eye. Previous macular spectral-domain optical coherence tomography images from the patient were available for comparison. Near-infrared reflectance imaging (NIR-R), taken 3 years before, demonstrated a cuff-type thickening of the arteriolar vessel wall at the site of the current complicated RAM that had gone completely unnoticed. These findings suggest that NIR-R may contribute to the detection of early damage of the arterial wall that may predict arterial aneurysm formation in hypertensive patients.