Browsing by Keyword "Sensing"
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Item Low-Cost Piezoelectric Sensors for Time Domain Load Monitoring of Metallic Structures During Operational and Maintenance Processes(2020-03-01) Perez-Alfaro, Irene; Gil-Hernandez, Daniel; Muñoz-Navascues, Oscar; Casbas-Gimenez, Jesus; Sanchez-Catalan, Juan Carlos; Murillo, Nieves; Tecnalia Research & Innovation; SMART_MON; SGThe versatility of piezoelectric sensors in measurement techniques and their performance in applications has given rise to an increased interest in their use for structural and manufacturing component monitoring. They enable wireless and sensor network solutions to be developed in order to directly integrate the sensors into machines, fixtures and tools. Piezoelectric sensors increasingly compete with strain-gauges due to their wide operational temperature range, load and strain sensing accuracy, low power consumption and low cost. This research sets out the use of piezoelectric sensors for real-time monitoring of mechanical strength in metallic structures in the ongoing operational control of machinery components. The behaviour of aluminium and steel structures under flexural strength was studied using piezoelectric sensors. Variations in structural behaviour and geometry were measured, and the load and μstrains during operational conditions were quantified in the time domain at a specific frequency. The lead zirconium titanate (PZT) sensors were able to distinguish between material types and thicknesses. Moreover, this work covers frequency selection and optimisation from 20 Hz to 300 kHz. Significant differences in terms of optimal operating frequencies and sensitivity were found in both structures. The influence of the PZT voltage applied was assessed to reduce power consumption without signal loss, and calibration to μstrains and loads was performed.Item Using an embedded Buckypaper to monitor mode I crack growth in bonded joints(2022) Gaztelumendi, Idoia; Villaverde, H.; Pérez, B.; Chapartegui, M.; Flórez, S.; Manterola, J.; Zurbitu, J.; POLIMEROS; PRINTEXStructural Health Monitoring (SHM) systems are commonly integrated in bonded joints for different applications in order to detect and predict potential fatigue and damages caused by internal and external agents they are subjected to during their operation life. However, each of the current SHM systems presents some drawbacks, as the reduction of structural properties or the difficulty in its implementation. This work deals with the use of a Carbon Nanotube film (Bukypaper) as a sensor in double cantilever beam (DCB) bonded joint specimens for crack growth monitoring purposes. Buckypaper (BP) sheets were manufactured and integrated in adhesive film layers and its integration quality was studied by Scanning Electron Microscopy (SEM). The effect of the integration of different thickness BPs in the mechanical performance of the bonded joints was also assessed performing DCB fracture tests. Also, electro-mechanical tests were conducted using the BP as the sensor, monitoring the output in the electrical resistance during the crack propagation. It was observed the capability of BP to detect and locate the damage during the test with a linear dependence between the electrical resistance measured in the BP and the deduced crack growth, proving the potential of the BP to monitor self-sensing bonded joints.