Browsing by Subject "fale Lamba"

Now showing 1 - 4 of 4

Access status: Open Access ,
Computer-aided prototyping of interdigital transducers for the structural health monitoring of planar structures
(2013) Mańka, Michał; Ambroziński, Łukasz; Uhl, Tadeusz
In recent years an intensive research activity into the application of guided waves (GWs) for structural health monitoring (SHM) can be observed. For instance, Lamb waves (LWs) have shown a great potential in monitoring of thin, planar structures. However, due to the dispersive and multimodal nature of the LWs, their snapshots can consist of many pulses even for an intact structure, which makes damage detection very complex. Moreover, small PZT transducers, most commonly used in SHM systems, act normally as omni-directional wave sources, therefore, dense or sparse transducers networks are required for damage localization. Some of the above-mentioned drawbacks of single PZT emitters and sensors can be overcome using interdigital transducers (IDT) designed to excite and sense a single, selected mode. The mode-tuning is performed by changing the span of finger electrodes to match the wavelength of the excited mode for the selected frequency. An IDT is a directional source, therefore, it generates a wave steered to the direction perpendicular to the electrodes. The width of the excited main lobe can be determined by the length of the electrodes. Since many parameters of the IDTs infl uence the LWs propagation, techniques for the simulation of the wave excitation and propagation are needed. In the paper, numerical tools for the computer aided design and virtual prototyping of the IDTs are presented. The simulation technique is based on the frequency-dependent transfer function of the structure, and due to its computational efficiency it can be used for fast testing of IDTs’ performance and for preliminary transducer design for further finite element simulations, and prototyping.
Access status: Restricted ,
Development of numerical modeling method for finite size interdigital transducer
(Data obrony: 2019-07-10) Kabała, Karol
Wydział Inżynierii Mechanicznej i Robotyki
Access status: Open Access ,
Interdigital transducers for lamb-wave based SHM systems: design and sensitivity analysis
(2011) Mańka, Michał; Rosiek, Mateusz; Martowicz, Adam; Uhl, Tadeusz
Structural health monitoring (SHM) systems have been constantly improved in the past decades. Sensors for SHM should be built-in to perform continuous measurements in opposite to non-destructive testing (NDT), in case of which sensors have to be mounted on the structure only during measurements. One of the most promising type of the transducers dedicated for SHM systems is Interdigital Transducer (IDT), which is designed for ultrasonic Lamb wave monitoring. Mode selectivity, high excitation strength, wave directivity, small size and relatively low cost are the most important advantages of the IDT. In the paper a designing process of the IDT is presented. Then, the results of numerical simulations and sensitivity analysis are discussed for exemplary IDT configuration.
Access status: Restricted ,
Zastosowanie MES do modelowania propagacji fal ultradźwiękowych w płytach o zmiennym przekroju
(Data obrony: 2019-07-15) Polak, Jakub
Wydział Inżynierii Mechanicznej i Robotyki