Papers by Keyword: Vibrometer

Abstract: The article substantiates consistent patterns of wear at the example of microcutting materials in sliding bearings in dependence to grain sizes of abrasive cloths and hardness of bearing layers received with the use of vibroacoustic diagnostics and the method of artificial bases (MAB) in testing on the SMC-2 frictional machine. These patterns can be helpful for the assessment of quality and selection of materials for products [1,2], selection of the friction model [3], and selection of abrasive cloths for the diagnostics of the latter and assessment of the running-in period for the top coating.

Abstract: Structural Health Monitoring (SHM) systems are developed to decrease the maintenance cost and increase the life of engineering structures by fundamentally changing the way structural inspections are performed. However, this important objective can only be achieved through the consistent and predictable performance of a SHM system under different service conditions. The capability of a Piezoelectric lead Zirconate Titanate (PZT)-based SHM system in detecting structural flaws strongly depends on the sensor signals as well as actuator performance. But service conditions can change the behaviour of transducers, raising questions about long term SHM system capability. Although having a clear understanding of the reliable sensor life is important for surface mounted systems, however, this is particularly critical for embedded sensors. This is due to the fact that opportunity for replacement of sensors exists for surface bonded transducers while for the embedded systems, sensor replacement is not straightforward. Therefore, knowledge of the long term behaviour of embedded-SHM systems is critical for their implementation. This paper reports a study on the degradation of embedded PZT transducers under cyclic loadings. Carbon/epoxy laminates with an embedded PZT were subjected to fatigue loading and their performance was monitored using Scanning Laser Vibrometery (SLV). The functionality of PZT transducers under sensing and actuating modes were studied. High and low cycle fatigue tests were performed to establish strain-voltage relationships which can be used to identify critical cyclic loading parameters (number of cycles and R value) under sensing and actuating modes.

Abstract: Historical structures, like to masonry towers and another structures are among the structures subjected to the higher risk, due to their age, elevation and low base area on height ratio. In this paper introduce a technique of monitoring the structural integrity of historical buildings by a noncontact and non-destructive analysis is presented and discussed. The damage and destroy of a structure and building, in terms of cracks and overall structural degradation, is detected throughout the measurement of its dynamic characteristics by various ways, for example by a laser Doppler vibrometer(LDV). These techniques can show the frequency spectrum of the structure with high accuracy and reliability and reaction of structure against this technique. Also we will introduce that timber components have no influence on the system behaviour, which is mainly determined by the properties of connections and reactions.