Energy harvesting technologies for structural health monitoring of airplane components - a review

With the aim of increasing the efficiency of maintenance and fuel usage in airplanes, structural health monitoring (SHM) of critical composite structures is increasingly expected and required. The optimized usage of this concept is subject of intensive work in the framework of the EU COST Action CA18203 "Optimising Design for Inspection" (ODIN). In this context, a thorough review of a broad range of energy harvesting (EH) technologies to be potentially used as power sources for the acoustic emission and guided wave propagation sensors of the considered SHM systems, as well as for the respective data elaboration and wireless communication modules, is provided in this work. EH devices based on the usage of kinetic energy, thermal gradients, solar radiation, airflow, and other viable energy sources, proposed so far in the literature, are thus described with a critical review of the respective specific power levels, of their potential placement on airplanes, as well as the consequently necessary power management architectures. The guidelines provided for the selection of the most appropriate EH and power management technologies create the preconditions to develop a new class of autonomous sensor nodes for the in-process, non-destructive SHM of airplane components.The work of S. Zelenika, P. Gljušcic, E. Kamenar and Ž. Vrcan is partly enabled by using the equipment funded via the EU European Regional Development Fund (ERDF) project no. RC.2.2.06-0001: “Research Infrastructure for Campus-based Laboratories at the University of Rijeka (RISK)” and partly supported by the University of Rijeka, Croatia, project uniri-tehnic-18-32 „Advanced mechatronics devices for smart technological solutions“. Z. Hadas, P. Tofel and O. Ševecek acknowledge the support provided via the Czech Science Foundation project GA19-17457S „Manufacturing and analysis of flexible piezoelectric layers for smart engineering”. J. Hlinka, F. Ksica and O. Rubes gratefully acknowledge the financial support provided by the ESIF, EU Operational Programme Research, Development and Education within the research project Center of Advanced Aerospace Technology (Reg. No.: CZ.02.1.01/0.0/0.0/16_019/0000826) at the Faculty of Mechanical Engineering, Brno University of Technology. V. Pakrashi would like to acknowledge UCD Energy Institute, Marine and Renewable Energy Ireland (MaREI) centre Ireland, Strengthening Infrastructure Risk Assessment in the Atlantic Area (SIRMA) Grant No. EAPA\826/2018, EU INTERREG Atlantic Area and Aquaculture Operations with Reliable Flexible Shielding Technologies for Prevention of Infestation in Offshore and Coastal Areas (FLEXAQUA), MarTera Era-Net cofund PBA/BIO/18/02 projects. The work of J.P.B. Silva is partially supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/FIS/04650/2020. M. Mrlik gratefully acknowledges the support of the Ministry of Education, Youth and Sports of the Czech Republic-DKRVO (RP/CPS/2020/003

Increasing The Efficiency Of Small Hydro Power Plant For Changing Water Flow

This paper deals with increasing the efficiency of a small hydro power plant in a low power operation. Problem of the low power operation is low efficiency. Both, turbine and generator, are optimized for nominal power. On the other hand, in the low power operation they have low efficiency. The losses in generator are analysed and possible improvements are suggested. This should contribute to higher efficiency in the low power operation. Water turbine efficiency is showed for different water flows and ways to improve efficiency for lower flows are presented. Calculation of nominal efficiency and possible new higher efficiency is made

Design Of Back To Back Converter For Small Hydro Power Plant

Renewable energy sources are important in recent years. Small hydro power plants are one of them which does not devastates the country, and which has relatively stable operation. However, in summer time with low river flow, they operate with low power and they have low efficiency. This paper demonstrates method to decrease the losses by back to back converter. Design of the converter is described, and fabricated part of the converter is depicted

Energy harvesting from passing train as source of energy for autonomous trackside objects

This paper deals with an energy harvesting review and analysis of an ambient mechanical energy on a trackside during a passing of a train. Trains provide very high level of vibration and deformation which could be converted into useful electricity. Due to maintenance and safety reasons a rail trackside includes sensing systems and number of sensor nodes is increased for modern transportation. Recent development of modern communication and ultra-low power electronics allows to use energy harvesting systems as autonomous source of electrical energy for these trackside objects. Main aim of this paper is model-based design of proposed vibration energy harvesting systems inside sleeper and predict harvested power during the train passing. Measurements of passing train is used as input for simulation models and harvested power is calculated. This simulation of proposed energy harvesting device is very useful for future design

Verified nonlinear model of piezoelectric energy harvester

Energy harvesting is an important topic today. Complex monitoring systems with many nodes need energy sources and vibration energy harvesters (VEHs) could be one type of them. Mathematical model of the VEH is necessary instrument to estimate possible harvested power. This paper deals with piezoelectric VEH in setting as cantilever beam with tip mass. Traditional linear model of this type of VEH is simple, however, it represents the VEH only in one operating point and in another one (another amplitude of excitation vibrations) it could return wrong results. The nonlinear model of VEH is introduced in this paper with its parameters estimation. The nonlinear model is compared with linear model and experiment to demonstrate difference between them in amplitude frequency characteristics. Finally, the average harvested power from harmonic vibrations is measured experimentally and compared with prediction from linear and nonlinear model

Reaktivita vnitřních a vnějších Bronstedových kyselých poloh v nanoporézních MFI: kinetická studie H/D výměny

The strength of Bronsted acid sites (BAS) affects the properties of 2D and hierarchical zeolites, but the relative contribution of internal and external BAS remains unknown. Accordingly, this study aims to assess the acidity of external and internal BAS in nanosponge-like MFI zeolites by comparatively analyzing hydrogen-deuterium exchange kinetics between zeolitic deuteroxyl groups and C2H6 molecules monitored by in-situ FTIR spectroscopy. For this purpose, (i) a sample pre-treatment procedure was specifically developed to deuterate only internal or only external acid sites using 2,6-di-tert-butylpyridine (DTBP) as a masking agent and (ii) DFT modeling of surface BAS was performed. Theoretical models of the thin MFI layer revealed that the external surface of MFI crystals contains three types of BAS: (i) BAS positioned in 5-membered rings, either shielded by silanol nests, rendering the site inaccessible for DTBP or yielding a very low adsorption energy for ethane, (ii) BAS pointing into the pores, due to the presence of aluminol, which hinders DTBP accessibility, or the BAS undergoes transformation to a three-coordinate aluminium site, and (iii) BAS accessible to both DTBP and ethane. The results from our kinetics measurements showed that H/D exchange at external BAS of nanosponge MFI zeolites is faster than at internal BAS (rate constants at 425 degrees C: 3.8 10(-3) vs. 2.4 10(-3) s(-1) for external and internal BAS, respectively), but this cannot be attributed to the effect of diffusion. Therefore, the differences in exchange kinetics between external and internal BAS are given by mutual interplay of subtle differences in the corresponding activation barriers (113 vs. 117 kJ/mol for external and internal BAS, respectively) and pre-exponential terms (1.09 10(6) vs. 1.45 10(6) s(-1) for external and internal BAS, respectively).Síla Bronstedových kyselých poloh ovlivňuje vlastnosti 2D a hierarchických zeolitů. Tato studie byla zaměřen na zhodnocení kyselosti vnitřních a vnějších BAS v nanoporézních MFI zeolitech pomocí komparativní analýzy H/D výměny mezi deuteroxylovou skupinou a C2H6 molekulami. Tato výměna byla monitorována pomocí in-situ FTIR spektroskopie. Výsledky byly porovnány s DFT výpočty modelujícími povrchové BAS